Pontiac Renovations, Part 29.

New workshop lighting

I finished up the workshop by replacing the original light fixture with a newer one. I still want to fit more lights but a couple of 40W tubes work for now. Better than having to fight flipping the light switch repeatedly to get the room to illuminate.


I bought a new set of points to fit in the distributor. The old set was a bit pitted (which did clean up) but the fulcrum was worn and the points would not align very well by themselves. I’d been seeing some misfire at higher engine RPM so figured it was worth a shot at replacing the points. It didn’t help much but it did at least eliminate that as being the cause.

Vacuum motor

Having been parked up int he garage for a while, the wipers stopped working. I took the motor apart and tried soaking the rubber seals in mineral oil to try make them swell up a little, but this was to no avail. It really just needs to be rebuilt. There is a firm in NY state that’s doing Trico wiper motor rebuilds so they’re on the to-call list.

Driver’s side brake drum

After the wipers, the car went on a little hiatus. I decided to finally do a little work on the car and adjust up the driver’s side brake because it would snatch and lock the wheel if the brakes were pressed moderately hard, instead of braking progressively. This is a sign of badly adjusted or contaminated brake shoes in drum brakes. I jacked the car up, pulled the wheel off and took the bearing race to pieces.

Front outer wheel bearing

With the outer bearings removed and cleaned I took a look at the brake shoes. They were greasy from where the bearings had been over-packed, which is never a good thing. The shoes also showed signs of having over-heated and the lining on the leading shoe is beginning to fall apart.

Bad shoe lining

Given that, I turned my attention to the drum, which was in good shape, albeit very greasy.

Crab pan

I traded a six-pack of beer for an old, beaten up aluminum pot from my neighbor, which I beat back into shape with a lump hammer.

Brake soup

I put the brake drum into the pot, filled it with dish soapy water and boiled it a few times to remove the grease. This proved most effective.

Fresh brake drum

I beat the bearing dust cap back into shape and painted the lot to stop it from flash rusting.

Brake fluid

I had tried the brakes with the drum removed and saw that only the rear shoe was being operated. I held the rear shoe and prevented it from moving and applied force to the pedal, which freed up the front piston. The wheel cylinder then began to leak badly from the newly moving piston. No good! Time for new hydraulics.

Warning lights

I made a little warning light panel to fit under the dash. The alternator has provision for a no-charge light (an accompaniment to the ammeter) and someone had fitted an oil pressure switch to the main oil gallery (in accompaniment to the oil pressure gauge).

Letter punches

I borrowed a set of letter punches and used them to press an impression of letters into the plastic of the light lenses.

Warning light panel installed

I decided on era-appropriate descriptions- GEN (for GENerator) and OIL. I dabbed a bit of black paint into the recessed letters.

After purchasing some correct Wattage bulbs, both lights function as expected. The OIL I decided to be orange because it is bright and that one I am much more concerned about. the oil pressure gauge is heavily damped, so doesn’t give a quick reading, the light comes on immediately below 5 PSI. The GEN light flickers and comes on at low RPM which is normal for this engine. I would need a smaller pulley to prevent that from happening, but it charges well over 800RPM.

Dual points conversion kit

Turning back to other issues with the car, I went on the look for a replacement distributor or vacuum advance plate. Someone turned up a new-old-stock dual points conversion kit, which I bought. This solved a few problems, primarily the lateral wobble in the old plate because it was bent and worn. Second, it extends the life of the points and decreases the need for routine inspection, cleaning and gapping. Third, it has an added benefit of extended dwell which allows the coil to saturate fully at high RPM (admittedly much higher RPM than my engine can achieve but the principle is sound).

Single points distributor

I took the distributor out and dismantled it.

Painted distributor

Being as it was out, I cleaned the rust off and painted the body.

Dual points distributor

I fitted a new condenser to the set and reassembled it with the dual points plate in, which moves very smoothly compared to the old one and also keeps the points in the correct plane with respect to the cam.

Spark wire manifold

Continuing with the ignition system, I removed the spark wire manifold, which was missing a part and also was all dented and dirty.

Straightened sheet metal

I hammered the sheet metal back into shape. I turned my attention to the lead-out tube which was missing the lower half (the curved section).

Lead-out tube lower panel

I bent, hammered and shrunk the metal into shape.

New spark plug wires

I painted it all up and fitted a new set of spark plug leads.

Wires fitted to engine

I gave a test-fit and that showed a significant improvement over the old set of leads; 4 new spark plugs of the 8 that I had ordered arrived, so I fitted them, switched out a couple of the older plugs and managed to get the engine running on 8 cylinders again. I need to tidy up a little bit but that’s progress, at least.

Back to cosmetics, the horn push had always been a sore point for me- the center of the emblem should be bright red, but with sun and time it had faded to a pale brown. I managed to take the thing apart by carefully bending the lip of the chrome surround ring up.

Lacquered emblem

I cleaned the old lacquer off, masked up and painted new red lacquer with the remnants of the red in the can I used for the rest of the badges on the car.

Reassembled horn push

I polished the clear cover as best as I could and reassembled it. A significant improvement, especially considering it’s right in front of you when you sit in the driver’s seat. Shortly after that, a mysterious benefactor sent another one that was in very good condition, with almost no crazing to the lens, which was very kind.

Slam panel

finally, I took the time to rebuild the cable and latch for the slam panel. All reassembled, the hood finally closes correctly and can be pulled open from inside the car.

Pontiac Renovations, part 28.

So, a new year and new things to do on the car. After having done a little work to clean some of the paint I decided to try mix up a color match for the 1957 Ford blue that is on the car.

The first attempt was not too far off but didn’t look right- the blue dried a lot darker than it mixed up. I tried again.

The second attempt came out a much closer match. Acceptably good, I touched up a few more of the spots where the paint had been knocked off, to try and protect it a little.

I touched up the back of the car to tidy it up a little. It all needs cutting out and new metal letting in but that’s a little ways off happening yet. It makes the car look better from ten feet away, at least.

I also made an attempt to flatten out the faces of the intake/inlet manifold, as it was not sitting well enough in all places to seal. Apparently common with long manifolds like this, it has warped with age and heat/cool cycles. I managed to get all but the center two exhaust ports flat enough to sit into the gasket; really it needs to be put on a milling machine and be milled down like the deck of an engine block. For now it is good enough that I can double-gasket the center two ports to get them to seal.

A little bit of pleasant weather allowed me to bring the car outside and start smartening the paint up. The roof has lost a lot of the clear lacquer, and I was trying to figure if I had wanted to polish the paint or not. If I were to polish it, re-applying clear lacquer would be difficult without almost completely stripping the paint back. In the end I decided to polish it up to seal it and protect what color is left. The mid-blue on the rest of the body responded well to wet-flatting and polish.

The roof has a nice gloss to it when finished well. I just need to carefully blend in the edges of the remaining clear coat.

The rear light lenses on this car are unique to the year- they are very bulbous compared to the preceding and following years, and are slightly smaller so the more common 1952 lenses, popular with hot-rodders are available easily and cheaply but these are not. The sun had done a number on these so I decided to try sanding one down and giving it a few coats of red lacquer to try and get a little more life out of it. the result is not perfect but looks much better than it did. I am also considering finding some reflectors to put inside because they are quite dim, even with LED’s inside.

I soldered in the brass overflow tube to the radiator and polished the radiator cap up. I do need to replace the cap as it is the wrong pressure (4lb instead of 7lb) but in the interim it looks better.

I took the front right brake to pieces because it was not really providing much int he way of braking effort and was quite snatchy. The lower adjuster was fairly easy to free up but the top one which has a large nut to hold it in place was stuck fast. I ended up having to borrow a larger socket from a neighbor and with most of my weight on a 5 foot extension bar finally managed to get it to free off.

Only a small portion of the threads had gone rusty but that, coupled with it having been done up by a gorilla, had meant it took upward of 2500lb/ft to undo. I cleaned it up and refitted it.

Armed with a copy of the manual pages pertaining to the brakes, I checked the shoes were free to move, both brake pistons were free to operate and then set the clearances and adjusted the shoes.

A few things arrived in the mail. first, someone sent me a gift of a replacement dome light cover as mine was long gone. This is a Chevrolet item but is not dissimilar to the Pontiac one and fits the same light assembly.

More goodies, in the form of a new “diode trio” for the alternator- the purpose of which is to feed half-wave rectified DC into the voltage regulator circuit to allow it to boost or drop the armature winding on the rotor and thus increase or decrease the output of the alternator.

Apart came the alternator again. Buried down in the depths is the offending article.

The diode trio was replaced (orange and black pieces, black being the new one) and the alternator reassembled. This provided a good output- I wired it temporarily to the ignition switch to get it to make the ammeter move. What I didn’t think about was how it was actually wired in; when I switched off the ignition the alternator was disconnected from the battery and no longer had a regulated reference so went into a free-running wobble which fried the 12-to-6 volt converter unit for the fuel gauge.

The car had also developed a bad misfire once it warmed up a little, resulting in clicking valve followers. I decided to pull the head off and soak the valve stems in Marvel Mystery Oil (which is essentially just mineral oil) to see if they would free up.

The oil was unsuccessful in freeing the valves up adequately- with the engine cold they would work perfectly for about 15 seconds before getting stuck open. In the interim I had ordered a replacement DC-DC converter for the fuel gauge which thankfully got it working again. I prefer it to have taken that out rather than burn the gauge coils or sender unit up.

My parents came to visit just before Christmas break, so the car took the sideline for a little while whilst much needed repairs were done to the house and workshop. The decking was replaced, and the roof repaired to the workshop and the walls replaced where they had rotted out as a result of the leaky roof.

The workshop was made significantly more airtight than it was, the little window unit air conditioner was taken apart and the mud dauber nests all removed meaning it had a chance of dehumidifying and cooling the area.

I painted the walls and doors white to cheer them up a little. After having done that I decided that it was too plain and needed something to make it a bit more interesting.

I bought some oil paint and painted a mural of the car, which was a nice distraction from the fact the car wasn’t running well.

I stripped the top end off the engine again and removed the valves (with thanks to Lloyd from the H.A.M.B. for the tool), a couple of which were very very difficult to remove from their guides.

I cleaned all the valves up, and let the collets and springs soak for a while to clean them up also.

I made a tool from an old toothbrush and a length of wooden dowel.

This allowed me to soak cleaning fluid down through the guide and scrub away any dirt.

I then made a second tool from another piece of dowel and a worn-out piece of 220-grit emory paper. That was spun down each guide to gently hone it, then the brush used to sweep up any debris.

I then started lapping the valves into the seats- they had been replaced by the previous owner but not matched (nor cleaned, from what I can tell) so this helped until I reached the third exhaust valve which didn’t want to lap in evenly. It turned out to be bent, from having hit a spark plug- guessing someone put the wrong length plug in and started the engine.

I ordered a replacement valve and once that came in the engine was reassembled.

The valves are awkward to get at even with the correct tools, but eventually I put them all in and set the clearances by eye.

I bought some tube and fittings and reconnected the oil pressure gauge. Now all my gauges work (though at 14.4V on the alternator the temperature gauge over-reads significantly. In that picture it should have been pointing just below 180) which is a nice thing to have.

I connected up the vacuum system from the manifold through to the pump and up to the windshield wipers. The vacuum motor is tired and really needs a rebuild. The washer pump is also similarly tired so work needs to be done there to make better.

It is nice to see the parts going back on the car though. Each makes it one step closer to working well.

Onward and upward. With the air filter removed the Carter makes a nice noise with the throttle opened up. It does run smoothly now.

Pontiac renovations, part 27.

With the engine and transmission back together, I decided to finish up doing the things that are difficult to do with the engine installed.

Looming tape

I wrapped the wires that are now in place (lights and such) and tidied up under the hood.

Delco 10si alternator ident

I undid the clamp bolt and cleaned up the body of the alternator. 1100542 shows it’s a Delco 10SI, 63 Amp remanufactured unit.

Alternator in pieces

I stripped the alternator down, thankfully Delco have the manuals online for their older models. There are 4 individual parts inside the end case; the rectifier bridge (silver finned heat sink), a capacitor, the voltage regulator (white plastic) and diode trio (orange).

The principle of the alternator is moderately simple. A magnetic field in the armature, created by passing an electrical current through a couple wound around it, rs rotated by the engine next to a series of wound coils (stator). As it moves past each coil winding, the change in magnetic flux generates an electrical current in the coil winding. As the magnetic field moves towards the coil, a positive field is created, as it moves away, a negative one is created. There are usually 3 windings (either in a Y or Delta configuration) so an alternator creates 3-phase alternating current. This is no good for a car battery which is direct current, so it is rectified through a bridge rectifier set of diodes before it’s connected to the battery.

This output is connected through the diode trio to the voltage regulator. The voltage regulator changes how much current passes through the winding in the armature, making the magnetic field stronger or weaker depending on how much voltage the stator coil windings produce.

The diode trio tested bad- two of the diodes are open circuit (do not conduct at all) and one doesn’t diode any more so that should be the root cause of the alternator not charging. The voltage regulator isn’t getting the voltage it needs from the output so isn’t applying voltage to the armature winding and the alternator is producing very little charge.

Valve lash adjustment.

I readjusted all the valves. The manual states to make sure they are all set correctly.

Installing engine

I bought some new bolts for the rear engine cradle, rated 8 (strong for shear force) with the correct fine pitch thread. That was cleaned and reinstalled and the engine wired in temporarily.

Securely mounted

It was good to see it back in. I set about reinstalling the ancillary parts and started to look at the manifold, which has never sealed well. It is made in two parts, with a “hotspot” flap in the exhaust that directs the exhaust around the outside of the intake by the carburetor before letting it escape though the downpipe.

Heating bolts

It was suggested that I split the two parts and re-settle them to allow them to seat square against the engine. Easier said than done, as all four bolts were seized and all four broke upon attempting to undo them, despite heat and releasing oil.

Drilling out old bolt

I carefully center punched the remains of the bolts and started to drill them out.

Cleaning threads

I then used a thread tap to clean the last of the bolt from the threads.

Original threads

The two most accessible bolt holes were straightforward, but the two at the back are obscured by the casting of the manifold and proved impossible to drill out straight. I ended up drilling them oversize and tapping the holes with a new thread.

Reassembled manifold

I made a temporary gasket and reassembled the manifold, which allowed me to put it back on the engine. It leaks but the correct gaskets are many times thicker and take up a lot of the gap.

Radiator hose

The original lower radiator hose was so badly rusted to the spigots I had to cut it to remove it. I took the old hose to the auto parts store and a replacement with the correct bend in was sourced. I cut it down to length and put the anti-kink spring inside.

Engine plumbing

I finished putting everything into the engine compartment that was required to make the engine run. I filled the radiator up with water and connected the fuel.


The three gauges that are currently connected all worked. Fuel gauge reads a quantity of fuel in the tank, engine temperature reads as it warms up and the ammeter reads a discharge.

First time outside in a while

I connected up the propeller shaft and took it for an experimental drive. The gears changed, it went forwards and backwards and overall worked.

Throttle linkage and spring

The throttle linkage was very sloppy and had a lot of free play. This was causing the gas pedal to move the gearbox modulator lever quite a distance before the throttle began to open, with the net result the gears were holding until high speed before changing and under light throttle were quite harsh.

Tight connection

I added some springs to the connections to hold them all in line, peened the bar of the throttle down to remove the slack and readjusted eveything as per spec. The result was as hoped for; gears that change gently under light throttle and more positively and at higher speed with heavier application of the gas pedal.

Testing wires

I started to track down a misfire under light load, I checked the spark wires for continuity. They are all good, but the insulation is poor so I think new ignition parts are required (cap, arm, coil, wires, plugs).

Water, soap and 2000 grit paper

I turned my attention to the cosmetics of the car because the weather had turned fine. I started to wet-flat the paint with dish soap, plenty of water and 2000 grit paper.


After finishing with the paper, I started to polish the paint with scratch remover cutting compound, then a finer grade polish, and finally wax.

Regaining a shine

The day became too hot to continue, as the polish was just flashing off, so I stopped. The improvement is noticeable.


I also masked up and painted the driver’s side hubcap with red lacquer. That made an improvement also.

Shiny paint

I loaded the car back up into the garage, and looking across the hood, I was able to smile. It is beginning to look nice. Much more yet needed, but this is a good start.

Pontiac renovations, part 26.

Work continued on the gearbox with the arrival of a box of parts.


A brand new oil delivery tube (for the clutches), a pair of clutch lids for the drums, new clutch friction material and steel packs, a set of new bearings and some other odds and ends.

Front servo

I started with the front servo, which was due new oil rings and a new main spring (the original fractured).

Front servo piston assembly

The front servo has a couple of independent pistons inside, separated by a couple of springs. It is all held in place by simple geometry and during assembly everything liked to get out of line. After a few failed attempts where springs launched themselves or the piston fell out past the rings I magnet to get it all reassembled.

Front servo rebuilt

I fitted new bearings (more on that later…) and started rebuilding the reverse gear mechanism.

Reverse piston return spring

The reverse piston is pushed back from being activated by a wavy spring steel washer. The original had broken in half. This appears to have been the reason the gearbox was taken apart originally. The broken part appears to have come free and become mangled up in the rear epicyclic gear set.

Brake light switch

I took a bit of a break from mechanical parts of the gearbox to work on the wiring. I fitted the replacement new brake light switch, as the old one had failed.

Headlight loom

I bought some new wire and rebuilt the headlight loom.

Turn and park light wiring

I redid the turn and park light wiring, as there were a bunch of Scotch-Lok connectors and excess wiring in the harness. I added a good ground and connected it all up.

Light wiring block

The wiring was then terminated at the rebuilt terminal block.

Bulb wiring terminal

I ordered some rivets, which are soldered to the end of a wire to form a terminal in bulb holders.

Rebuilt bulb holder

With the bulb holders rebuilt, I started to run new wiring under the dash.

Wiring spaghetti

This began to turn into a complex task, despite the wiring in the car not being too many circuits. The brake lights and front indicators all wire through the turn signal switch.

Turn signal flasher and switch connector

The original connector was loose to the switch and the wiring was a little crispy. I took the connector apart and started to de-solder the wiring.


This demonstrated just how flammable the old wiring is- it caught fire very easily and did not put itself out.

Flasher circuit harness

The harness was loomed up neatly, with wires for the brake lights, front indicator bulbs, wiring to the brake light switch and wires for the dashboard telltale lights.

Dash harness

I built the loom up for the dashboard and connectorized it for easy connect/disconnect.

Dashboard lights and gauges

I connected the dash up to test. All the lights work, the dash dimmer operates, the ammeter registers current and even the fuel gauge registers not-empty.

Clutch pack debris

With wiring completed, I turned my attention back to the gearbox. I pulled the clutch packs apart and discovered a lot of metal debris inside, a lot of melted alloy.

Annular piston

I fitted new bearings to the clutch pack after cleaning it all up. The new parts fitted together nicely.

Clutch pack reassembly

The clutches are made up of a number of rings, friction material rings with centered teeth that grab the sun gear and steel plates that locate on pins to lock the gearset solid and stop the thing being in reduction.

Clutch pack rings

With all the clutch rings in place, the piston assembly then sits in the top and is held is place with a large snap ring.

Front and rear drums

The drums then locate onto the fluid delivery sleeve, which in the book calls for a special tool to compress the oil rings down for easy assembly.

Improvised tool

I improvised and wrapped wire around the rings to hold them compressed.

Front drum on

The front drum went on easily because access is good.

Both drums on

The rear drum… not so much. However, both fired on successfully after a long fight.


I then started to refit it all into the case. I then started to run into trouble with it all not fitting. I decided I needed to order some more parts to adjust lash.

Dirty chrome

While I was waiting for parts I went back to working on the wires. Part of that included wiring for the heater fan. The fascia panel was particularly dirty so that was cleaned up.

Dirty panel

The switch for the fan was rewired at the same time, the switch itself being in good condition.

Clean panel with switch

I rebuilt the dome light because the switch did not work. It had corroded and the contacts had become poor and had caused the plastic to become distorted.

Dome light switch

A little work with a craft knife and sandpaper saw the plastic in the correct shape again with the slider being spring loaded against the terminals.

Dome light switch operational

I then had to rebuild the driver’s door switch as it has seen some water ingress and was also corroded.

Door plunger switch

Now the dome light and trunk light both operate (though the trunk light mercury switch is unreliable).

Antenna installed

I fitted the electric antenna I had bought and tested operation, successful. No radio yet installed but it’s ready to go.

Bent steel

I had wanted to purchase an alternator that is fitted into a case that looks like the original dynamo generator, for two reasons. Firstly, the look of it and second, it utilizes the original mounting points. However, those are very expensive so instead I decided to build a bracket that mounts to the original points but correctly holds the alternator in line. Previously the alternator was mounted upside-down, with the main mounting point providing no reaction torque and the adjustment bolt hole holding it all up. As a result the alternator was sitting at an angle and the belt was slipping.

Alternator bracket

The new bracket holds the alternator in line with the pulleys and allows now for correct adjustment.

The alternator warning light won’t go out and I get just over 13 volts from it, so further investigation is required.

Timing marks

While I was working in the area, I cleaned up and painted the timing marks. There was a blob of white paint that covered all 3 marks (at 3 degree intervals). I found the timing was set very far off, close to 45 degrees. I re-indexed the spark plug wires and discovered the engine was very happy to idle smoothly when the timing was correct.

Clamped vacuum advance

I saw with my timing light that the ignition wasn’t moving with manifold vacuum. Discovered someone had clamped the vacuum advance arm with the condenser bracket. I freed that up and found the screw holding the condenser was far too long, had fouled the mechanism underneath and the plate was bent. I corrected that so now it advances but it does move a little far. There is a bendable tab that limits how much advance is applied, which will need modification to prevent light throttle from being lumpy without impacting idle.

Headlight beauty ring clip

Between times I had a thought and decided to make a new clip for the driver’s side headlight beauty ring. I had some baling wire, which is nicely flexible but has all the strength of putty. So, I bent the wire to shape then heat-treated it with my propane torch.

Heat treatment

The wire is heated to incandescent orange then quenched rapidly in cold water. This hardens the metal. A couple of repeats, then heating the metal up to a dull cherry red and letting it cool slowly brings back capability to be springy.

Headlight trim

The headlight trim is now securely held in place, which is an improvement over the previous implementation courtesy of the previous owner of gooey sealant. Which, incidentally didn’t work.

Gearbox reassembly

A bit of a saga occurred with the gearbox. I couldn’t get the main shaft endfloat correct. Everything was too tight and would bind up solid. I figured perhaps a bearing hadn’t seated well so gently tapped the mainshaft against the rear drum. This translated the force to the oil pump, which was the root cause of the problem. The bearing hadn’t seated correctly when I put it in and was sitting proud. As a result the retaining flange on the oil pump shattered (I think it had been weakened in the past). I ordered a new oil pump and the correct thickness shim which allowed me to reassemble the gearbox.

Rear servo measurement

The brake bands need to be carefully preadjusted for correct operation. The manual shows the use of a special tool- with care vernier calipers can be used. The setting is to dial the band in against the spring until the distance from the back of the servo to the actuator pin is 5 7/16″.

Rear band adjustment

With tension set, the locknut is tightened down and the rear band is done.

Front servo adjustment tool

The front servo needs to be pushed in 300 thou’ and the band set snug at that position. The servo case has a plug in the end which is tapped blind so it seals. The brass insert is a hydraulic fitting that I tapped a thread through to allow a bolt to be screwed down and push against the piston.

Domed end

I filed and rounded end onto the bolt and polished it so it could turn and push against the alloy piston without damaging it.

Front servo preload

A little bit of mathematics showed with the thread pitch of the bolt 5¾ turns were required for 0.3″ of travel. I set the front band against this and reinstalled the servo plug.

Painted gearbox

I reassembled and painted the gearbox.

Engine and transmission

I then cleaned up the flywheel and bolted the gearbox to the engine. I gave the engine an oil change and filled the gearbox with ATF. I started the engine up and engaged Drive and was greeted by the gearbox changing through all gears as the revs were brought up.

Pontiac renovations, part 25.

I continued to work on the parts of the gearbox, stripping everything down. A large volume of swarf, metal chips and bits of burned friction material from the clutches had found its way into the hydraulics.

Front drum

I managed to clamp down and disassemble the clutch packs. All the friction material (an organic fibrous material and come cork) on the friction rings was gone, burned to a crisp. The six light spots are bright patches worn into the metal.

Rear drum

The rear drum was significantly more difficult to take apart. It is not internally spring loaded and is a tight interference fit. It was less badly worn but still unserviceable.


With the drums apart, I checked the thickness of the thrust washer shims. They were below limits.

I ordered a pair of new ones. The copper is completely worn through on one of the old ones.

Valve block

The cleaning continued. I disassembled the valve block, which was all partially jammed up with dirt and swarf. The bores and pistons were all in good shape, and upon reassembly all move well.

Servo spring

I started to disassemble the rest of the hydraulics. The front servo relinquished a fractured spring. This is going to be the main causal reason the gearbox failed, with this slipping there is extra stress on the clutches.

4-3 downshift valve

I invested in a large screwdriver and was able to remove all the plugs from the front servo. The 4-3 downshift valve (above) is a good example of how dirty the hydraulics in the system were.

I had a little difficulty disassembling the front oil pump, because the thing was held together with 4 Fillister head screws, all of which were stuck fast with sealant and all had been previously rounded off. One needed to be sawn down and another drilled. The pump itself was in surprisingly good shape inside, considering the amount of swarf in the rest of the pipes. The overpressure relief valve (the dark circle on the bottom right of the right hand assembly above) was also jammed, so that was freed up and cleaned out.

Rear servo, in pieces

The rear servo is fully spring loaded. It holds the rear band on when the gearbox is not pressurized, meaning that if reverse is engaged it has both reverse and 3rd gear selected simultaneously. This effectively locks the gearbox solid and acts as a parking brake.

Rear servo, assembled

I managed to reassemble the rear servo without losing any parts or breaking any of the oil rings. There’s enough tension in the spring to launch the thing into orbit.

Reverse gear

Finally, the reverse gear assembly.

The reverse gear cone is a little scored- turns out there’s been some swarf stuck in it and that’s caused hotspots. I picked all the steel out of the alloy. Thankfully this mechanism only comes into contact with the drum when reverse is engaged, and only slips of the vehicle is moving when that is done.

A good drum

In contrast, a new drum is fairly smooth. (Above).

Special tool

The annular piston that forms the central drum cone is held in by a disc and a snap ring. The disc needed to be pushed down, compressing the springs so the snap ring could be removed.

Modified valve core

I trimmed the base of a valve core flat so it would seal against the case.

Reverse cone removed

Application of compressed air saw the piston removed. Surprisingly, this was the only part of the system not full of swarf and dirt. The seals were fairly new (though in bad condition) and the roller bearing at the back is quite new also. The reason for this became apparent when I found half of the wavy washer under the retainer in the drum. It appears that fractured, came loose and jammed the reverse gears, causing a bit of damage. Someone had taken it apart, done half a job to pull the pieces out and thrown it back together.

Removing seal

I overhauled the reverse mechanism. Removed the seals, cleaned the grooves they sit in. Whoever was inside the gearbox previously neglected to do this.

Cleaning sealing surfaces

The sealing surfaces were not very clean so I rubbed then back with 1000 grit paper until they were smooth.

New seals were applied.

Reverse gear assembly

I reassembled it all, having to improvise another special tool to get the outer lip seal to be able to get past the step the static outer cone sits in. Now awaiting new bearings.

Governor and rear oil pump

The governor assembly was also in need of cleaning. The smaller governor weight would stick at the bottom of it’s bore because it was worn. I lapped it carefully with some metal polish and now it doesn’t jam- the piece it used to get hung up on doesn’t need to seal, it simply needs to prevent the piston bottoming out.

The governor is two parts- the left hand one has a large weight and opens up that valve at low road-speed. That engages the reverse gear lockout pin. The smaller of the two pins is thrown out at higher speed, and provides pressure to the valve block to engage different gears as the speed of the car increases. If the pin sticks then it will change gear too late each time.

Pontiac renovations, part 24.

Strip-down of the gearbox began in earnest. With the service manual in hand, I was able to determine the correct procedure to dismantle it.

Upside down

The manual states the first thing to do is to upend the gearbox and mount it in the gearbox holding jig. I don’t have a jig so it just sat upside down on my new bench instead.

A volume of dirt

First impressions upon removing the oil pan were not good. There was a lot of black gunge, which draining the fluid belied, being rather clean red when it came out.

Dirt flushed

I flushed a lot of the dirt out, which left behind a lot of metallic swarf and a few molten globules of metal. Not a good start at all. I was hoping at this point it was merely remnants of a burned up clutch plate.

Clean oil pan

I thoroughly cleaned the oil pan and leveled the gasket surface with my orbital sander.

Clean steel

I then cleaned the old paint and rust from the exterior of the oil pan. Originally the pan was zinc coated and not painted; somebody had painted it gray in the past.

Painted oil pan

The original color is battleship gray, but I opted for Solstice Blue again.

Oil filter

I removed the gauze oil filter. Somebody had added blue sealant to the rear pump pickup point. This made me cringe.


I began to follow the manual to remove the control block, reverse control and band servos.

Planetary sets and reverse

That left the core of the gearbox in place; the front and rear planetary sets and the reverse mechanism. I removed the reverse gear assembly and undid the main bearing cap holding the two planetary gear sets in.

Rear assembly removed

I removed the snap ring holding the rear assembly in place and pulled it off the fluid delivery sleeve (the section that provides hydraulic pressure to the clutches). At this point I was able to determine the source of the swarf and metal shavings in the oil pan.

Oil delivery sleeve

One oil control ring was fractured and the sleeve itself was very badly scored. The sleeve should not make contact with the drum at all where the rings are.

Overheated bearing

The bearing surface showed it had overheated and worn away significantly, allowing the drum band system to pull it off center and force contact with the oil delivery sleeve.

Main bearing

Removing the snap ring from the front assembly showed similar damage to the bearings, allowing it to be well off center and tear up the fluid delivery sleeve on this side also.

Main driving shaft

The main driving shaft (output of the primary epicyclic to the fluid coupling torus) is made of much tougher metal than the fluid delivery sleeve and has escaped much in the way of damage.

Thankfully, parts are available and I will be able to rebuild all the damaged sections. I need to take the assemblies apart and check the clutches for condition.

Pontiac renovations, part 23.

August rolled around again, and as it is wont to do, has been warm.

Warm in the garage

Having spoken to a radiator shop and been quoted a significantly higher price than I could afford for repair, I decided to set about and attempt a repair on my radiator myself.

Filler neck

The filler neck had what looked like some sort of putty or mastic spread all around it in a messy fashion.


I pried at it a little with a screwdriver and a large chunk fell off, showing it to actually be lead solder. Whoever put it on did it badly.

Filler neck removed

I decided to cut my losses, and while holding the cap in my big pliers, I heated it up with my gas torch. It popped off with relative ease, showing a lot of dirt where it had split away from the top tank, and was being held in place around about one fifth of it’s circumference.

Cleaned with wire brush

I used a steel wire wheel to clean both the top of the tank and the filler neck. I then added soldering flux, heated them both and tinned them by adding solder to each face, ensuring good adhesion.

Filler cap soldered in place

I then lined the two pieces up and heated them so the solder flowed and melted together. Hopefully a permanent repair.

Big gas flame

The radiator had been leaking along the seam between the fins and the top tank. I cleaned it up and attempted to solder it up with my gas torch, which proved to have a flame too broad and too hot to easily work with.

Soldering with big flame

I was able to make a good seal, but it wasn’t the tidiest of work. I went to the store and bought a torch with a much tighter flame pattern, adjustable temperature also.

Small torch

The tighter flame allowed me to control the heat better, and so I soldered up the rest of the seam.

Seam soldering complete

This method allowed me to improve my technique and make a much more tidy repair.

Pressure testing

I built a rather Heath-Robinson testing rig, consisting of the garden hose and some duct tape.


With the seam no longer leaking, the pressure testing identified a small crack in the top tank.


I cleaned the area around the crack mechanically with a wire wheel, then chemically with acid flux.


I soldered the crack up and tested it again. This time it didn’t leak.

A bit of black paint

I cleaned the metal down of old flaking paint and gave it a coat of semi gloss black. I ran out of paint, will continue the rest with a new can.

GM Hydra-Matic notes

As a side-note, the gearbox is specified in a strange way compared to automatic gearboxes I am used to. Most modern automatics have the engine drive the torque converter housing, which turns the pump, and the inner vanes of the torque converter drive the mainshaft. The output of that is then passed through the reduction gears.

Pontiac specified that the vehicle should not creep at idle, in Dr (drive) position. Even with the engine idle specced lower than the manual gearbox version (375 versus 550 RPM) the fluid coupling imparts enough force at 375 RPM to move the car forwards. At a guess the rationale for this was to not alienate their customers who had never experienced an automatic gearbox before.

Get in, sit down, start up and put it into gear, look there, the car does not move.. gently squeeze on the gas pedal sir.. there, the car begins to move- press a little harder, and just take your foot off the gas and onto the brake to stop. Yes, just like that sir, isn’t that a fantastic marvel of modern technology?

To stop the car from creeping yet retain an acceptable idle (the engine gets a bit unhappy as it approaches 300 RPM or lower) the engine drives the outer coupling housing directly (which is not connected to either inner torus) and that is taken inside the gearbox and through a 1.45:1 epicyclic reduction gear. The output of that is then sent back to the driving torus at 7/10 the speed of the input. As a result the driving torus is turning at about 260RPM at idle. At this speed it does not impart enough torque into the driven torus to move the car.

The output of the driven torus goes back deep inside the gearbox and drives a second epicyclic reduction gear of 2.63:1 ratio. The two gears driving each other in reduction results in an overall gearbox ratio of 3.82:1 in first gear.

The epicyclic reduction gears can be locked by the internal clutches to either reduce the output speed or be locked solid at 1:1 ratio. Combining the 2 clutches in a binary style fashion (00 01 10 11) provides 4 reduction options- 3.82:1, 2.63:1, 1.45:1 and 1.00:1 (direct).

The final drive passes through a third epicyclic gear, which, by holding the planet set still with a clutch will reverse the motion of the output shaft and provide a reverse gear. It is also locked out internally to first gear full reduction only- without that there would be 4 speeds in reverse with a top speed of about 60mph. Not ideal!

The gearbox also has a few interesting design features- two oil pumps, one on the engine driven side, the other on the output shaft. This is to allow oil pressure to be built up as the vehicle is towed, for two reasons. First, it provides lubrication without the engine running, second it provides oil pressure so that if the transmission is dropped from N to Dr it will engage a gear and be capable of bump starting the engine.

The oil pumps are designed to provide high pressure at low speed. This pressure is kept constant by a spring relief valve. The gears are selected by valves with varying strength springs. A governor valve (centrifugal weight that spins with road speed) increases pressure on the valves as the road speed changes, initiating gear changes. The throttle pedal is attached to the gearbox and serves two functions. First, it opens a valve that applies main pressure to the opposite side of the gear shift valves, meaning greater governor pressure needs to be built up before the valves will move and gear changes occur. Second, as the gears are changed it adds boost pressure to the servos so the bands clamp more firmly and quickly. This makes low speed, light throttle gear changes smooth to engage at low speed, and hard acceleration changes to snap tight quickly at higher road speeds.

It all sounds good but there are a lot of moving parts that all need to move in synchrony. If something jams, it’ll either disengage drive fully or attempt to engage two gears at once which causes undesirable operation, neck-snapping jerks in the drive or a redline-flare of the engine. In this case, it would change gear at a much higher RPM/roadspeed than it should have, and only when the throttle was snapped shut. Hopefully that can be remedied.

Pontiac renovations, part 22.

I started to strip down the parts of the gearbox I knew how to take apart, having ordered the service manual but still waiting for it to arrive.

Fluid coupling driving torus

The fluid coupling is all held together with a large nut, secured with a tab washer. The tab washer was a good idea by the engineers because the nut, initially torqued to 50 lb/ft, was loose.

Fluid coupling parts

The large drum section connects directly to the engine flywheel (and represents a significant rotating mass to act also as flywheel) and the two torus sections sit inside and drive each other.


The inside of the bellhousing was fairly clean, though it is easy to see where the O-ring has been leaking past the torus housing. The inner part of the torus is kept full of fluid by the pump and at about 40psi by a pressure relief spring. The mainstay of the oil is kept in by two piston rings on the inner edge.

Gearbox, bare

The bellhousing came off easily. I cleaned the machined faces up and inspected the seal.

Side pan

I removed the side oil pan from the gearbox. It was rusty and the previous keeper(s) had painted it gray over rust and dirt. I cleaned it up with orbital sander and wire wheel.

Painted pan

It then received a couple of coats of Solstice Blue paint, as a test. I see no reason why engine parts cannot be any particular color. It won’t last but it’ll start out looking nice.

Ignition timing clamp

I cleaned up the distributor clamp, which has a moderately helpful pointer (which will need to be reset) to show degrees of advance or retard against TDC (Top Dead Center).

Timing marker

There’s a cast vee in the case of the engine to refer against, and the distributor also has a knurled wheel to fine tune the timing.

Service manual

The service manual arrived. It’s in good condition, printed in May of 1951. It gives a good explanation of how the gearbox actually works.

Measuring main shaft endfloat

I clamped my dial gauge to the gearbox and measured the endfloat. This is set by a bronze thrust washer buried deep down at the back end of the gearbox. 19 thou’, slightly over limit. If I can get a replacement shim I’ll fit it, else that’s on the next big service.

Engine, in turquoise green

I decided to finish up something I had started a good while back. I cleaned the engine down and gave it a coat of paint.

Other side

It is meant to be something close to Brunswick Green, but I cannot find that color anywhere, and the nearest green (Hunter Green) is horrible. So, I went slightly out of the box and painted it a color called Deep Turquoise. It’s close to the mid sixties Pontiac V8 color, And goes well with black parts attached.

Harrison 3127575

I brought the radiator to a shop in town, and their main guy took a look, measured it up and said it would need to be recored, at $460 for the core and about 6 hours of labor to total approximately $900. I am going to clean it up and attempt to plug the hole and make do for now. Sometimes these things price themselves out of the market.

Pontiac renovations, part 21.

July has been a busy month; an early hurricane saw me climbing on the garage roof in the middle of the storm to nail down loose corrugated iron panels.

More work with orbital sander

I continued to work on the firewall of the car, removing old bubbled paint and rust.

Frame rail

I also started to clean up the X brace of the chassis, before putting the engine back in rendered access impossible. Rust converter solution, black paint, underseal then a coat of black on top to cover up the brown of the underseal.

I put some paint on the firewall to protect it, which was a marked improvement. My neighbor had offered to weld the horns to the brackets, so one afternoon this was completed.

Welded brackets

A quick coat of gloss black enamel…

Gloss black

Then a test fit to the firewall. They don’t look out of place a great deal, being a little too modern.

Horns fitted in place, with relay.

Then, with that diversion over, it was back to scraping dirt and rust.

Mostly old dirt.

This was scrubbed and painted up to try protect the metal again. It’s all in remarkably good condition for its age.

Undersealed and painted black.

With the lower sections cleaned and painted, I started on completing the firewall. It was scraped down and painted.

First paint coat.

I then masked off along the body pressing lines and coated the lower sections in rubberized underseal.


The factory had applied a similar coating to the underbody, but had left it unpainted (plus they didn’t mask, they just sprayed the stuff on from a distance at high velocity) which looked a bit ugly. Similarly I decided that I was not going to leave it like that, as I didn’t like the blue/brown contrast.

Underseal painted blue.

I painted over the top of the underseal. Looks quite acceptable now.

Inner fender apron

The driver’s side inner fender apron was looking a little worse for wear. Originally the battery was mounted hard up against the sheet metal, and years of leaking acid had taken its’ toll.

Paint removed from sheet metal.

I sanded the sheet metal down. The wrinkles look like accident damage but are in fact factory produced. The metal is a complex shape and did not shrink cleanly when it was stamped. As an internal panel this was evidently deemed acceptable.

Channeling my inner Bob Ross.

I applied rust converter solution to the panel, which dried quickly in the heat.

Semi-gloss black (still wet)

The entire panel then received a couple coats of black paint. A significant improvement.

A little bit of a hallmark day; I started to put things back onto the car. The brake pedal was reattached and the kick plate fixed into place.

Grease gun in action

I bought a decent grease gun, as the car has many greasing points that need regular attention. I started with the brake pedal hinge.

Steering box, being cleaned

I then cleaned all the old grease from the steering box with gasoline and a paintbrush.


It was then refilled with John Deere Corn Head grease, which looks like green ketchup. That was squeezed into all the bearings.


I then reassembled it all, adjusted as much slack out as I could and rejoiced at brakes AND steering. The steering box is worn and really needs the gears and plain bushings replacing but it’ll do for now.

Dimmer switch.

I then cleaned up the contacts and body of the headlight switch, and refitted it to the floor. Finally, the carpet went back down in the cabin which is a nice change.

Vent duct, rust.

I cleaned up the driver’s side fresh air vent duct, as it’s on view in the engine compartment.

Clean vent.

Who doesn’t like gloss black enamel? It gives a nice finish. That’s tidy enough to refit now.

Draining gearbox oil.

I turned my attention back to the mechanical parts. I drained the gearbox of oil, which looked a really very good color- it’s not done many miles since someone was in here last.

Removing torus bolts

The fluid coupling torus housing is in two pieces. One half forms the engine flywheel plate, and is held together with 30 bolts around the periphery of the assembly.

Gearbox, split.

I was able to put a bolt in the top of the casing and use my engine crane to separate and move the gearbox away from the engine. It is too heavy to lift manually, and as such cannot be put on my workbench. I didn’t want to work with it on the floor so built a workbench to put it on.


I lifted the side pan off to inspect a little. While fairly clean inside, all the mechanisms are under significant spring tension and I didn’t fancy undoing things before knowing the disassembly procedure. Service manual is in the mail.

Control valve and reverse gear mechanism

As such, I went looking for other things that needed to be done while I wait for the manual to arrive.

Fiberboard insulation, broken

The headlight connector blocks were in very bad shape. The insulators are made from fiberboard and hadn’t stood the test of time well.

Brown plastic

I took some brown plastic, drilled holes in it and cut it to length.


Filed the notches along the length that prevent the connectors rotating.

Then cleaned up and attached the metal connectors. Headlights, sidelights and turn signals connect to this block. Ground goes direct to the bodywork.

Attached to the car

Pleased with that result, I made a second one for the other side. Unfortunately half of the connectors are missing, so that’ll be other connectors in their place.

Passenger side connector block

This is beginning to pave the way forward to rewiring the car. Any progress is good progress.