Monthly Archives: January 2019

Pontiac renovations, part 9.

Spent a little money on things for the car this time around.

A brand new, 3-ton low-profile shop jack. It has the capacity and lift capability to raise the car up off the ground safely. My small trolley jack was not capable and did not fit under the car, as it was too tall.

Work started on the windshield wipers, which had never worked since I got the car. They would attempt to move a little bit but that was it. They would not stay running, instead would just hiss. With the wiring removed from up under the dash, access was significantly improved.

Remove wiper control knob.

First, the control knob for the wipers was removed. This has a small gearbox and a wire in a Bowden cable that runs to the wiper motor to actuate the valve.

Locking collar.

Knocked the locking collar off the control with a screwdriver. I’m not sure why there’s a large washer under the knob, I think this is incorrect.

Trico vacuum wiper motor.

The wiper assembly is manufactured by Trico. I’d never taken one of these apart before, so a learning experience in vacuum motors was to be had.

Flip-flop valve assembly.

The side panel came off to reveal a spring-loaded flip-flop that’s activated by the motor spindle when it reaches the end of its travel, and a plastic valve that directs the vacuum to one of two ports at a time.

Wiper motor apart.

The wiper motor is predominantly made from the semicircular lower section. A flap is drawn from side to side, and the grease inside forms a seal. The grease had dried up and the seal was poor. I cleaned everything out and re-greased it.

Oiling the Bowden cable and gearbox.

The Bowden cable was stiff to operate. It had a couple of kinks in which I straightened out between my fingers, and it was oiled and left to soak. This significantly improved its’ function.

Vacuum pipe, polished.

Because it was out, I polished the pipe that takes the vacuum. Sadly someone has shortened it, so it may be changed again for a new stainless pipe.

Reassembled and tested wiper motor.

The motor was reassembled and tested. It operates smoothly and with significant force. The self-park also works- in operation the wipers will wipe an arc on the screen away from the edges, switched off they tuck themselves down tightly against the frame of the window.

Access to wiper spindle.

The wiper arms, now disconnected from the wiper motor were difficult to move, particularly the driver’s side. With the dash removed, access to undo the wiper mechanism is good, so I undid the driver’s side spindle clamp.

Escutcheon removal.

Breaking the old seal, I removed the wiper escutcheon and linkage from the car.

Driver’s side wiper linkage.

Lain out, the assembly is in remarkably good condition, just dirty. I tried to move the spindle by hand and it was very difficult.

Penetrating oil to remove dirt and rust.

I soaked the spindle down with penetrating oil, which washed out a lot of dirt and rust. I then finished up with regular engine oil which made the assembly easy to turn.

Cleaned and lubricated spindle.

It was left to sit for the night and drain down.

Driver’s side wiper hole.

I cleaned up the hole left by the mechanism. There’s a little rust which will require treatment before reassembly.

Glove box.

I then fought with the glove-box. It is a hardboard affair, held in place by screws. Removed, access to the passenger-side wiper mechanism is straightforward.

Hole at bottom of thread.

Inspection of the passenger side escutcheon showed something I hadn’t spotted on the driver’s side because it was obscured by dirt- a slight drill-through from the screw-hole that the mounting bolt fit into, through to the inside of the shaft area.

Squeezing grease into screw-hole.

I began by squeezing grease into the screw hole.

About to force grease down with bolt.

Then, forced the grease down by screwing the mounting bolt into the hole. This was successful until the interior filled with grease, whereby more grease would escape through the threads of the bolt than was forced through the bearings.

Grease nipple fitted.

I had a thought and went offered the mounting bolt up against one of the grease nipples on the front suspension. It looked to be about right so I undid it and fitted it to the wiper linkage. A perfect fit.

High pressure grease gun.

Grease gun fitted to the nipple, and fresh clean grease pumped into the assembly under significant pressure.

Dirty grease expelled.

This started to force dirt and rust out through the bearings. Rotating the spindle back and forth proved an effective way to clear the bearings out.

Lubricated assembly.

All cleaned up and free to turn, I turned my attention to the seals. New ones are available but I had bought some high density foam rubber to repair the rear light seals on the Renault a while back.

Paper template.

Cut out some paper and made a pencil rubbing of the edge of the mounting hole in the top of the scuttle.

Cut out and transferred the shape to foam, trimmed everything up to fit.

Seals fitted.

Both linkages fitted with seals. If these don’t work I’ll get some proper ones.

Rust converter.

Final thing was to apply some rust treatment to the exposed metal. That’ll dry thoroughly, receive a little paint and have the wiper assemblies refitted.

Pontiac renovations, part 8.

I refitted the now-clean headlight switch back to the dash. Unfortunately now the rest of the dash dials look dirty in comparison. I shall have to remove the heater controls and clean them also.

Headlight pull-switch (in second position)

Electrical work continued with gauges. The fuel gauge was similarly burned up inside, along with the temperature gauge. Measuring the diameter of the wire on the fuel gauge coils showed it was the same diameter as the new wire I had bought.

Measuring wire gauge with micrometer.

The mounting bucket was also showing signs of age; the paint was flaking off from heat and there were scorch-marks one the paint also. Cleaned down the original paint (which came off very easily with carburetor cleaner).

Clean mounting bucket.

Counted the number of turns on the fuel gauge and re-wound the spool carefully. Testing on a battery with 6V converter in place- I decioded to use 6V because the wire gauge was the same as original, lower current through the sender in the tank and everything could be set up identically to how it was removed.

Calibrated the irons to the correct resistance values -0, 15 and 30 Ohms. 15 Ohms showing middle-of-the-range.

Mid-way calibration mark- 15 Ohms.

I then began to readdress the temperature gauge. Operating it at 6 Volts showed there was insufficient magnetic flux in the middle of the needle’s range to hold it in place over the friction of the pivot.

Six volt test.

Operating it at 12V as originally intended solved this but I had wound the coils for the original spec sender unit, which is no longer available. The original sender unit had a very low range of resistance values for temperature, 100F being about 300 Ohms. I purchased a (slightly) more modern sender, a Wells TU-4. It has approximately twice the resistance per temperature, is physically the same size and is more readily available, as it fits mid 50’s Chevy trucks.

Sender unit in hot water, with thermometer.

I decided to abandon attempting to calibrate the gauge while connected and instead started plotting temperature versus resistance on paper.

Wells TU-4 resistance curve.

The gauge is wired in a Y-configuration- I had missed this previously. One coil is directly across the supply voltage, the other is across supply through the sender. I decided that I should be able to add a resistance across the other coil and reduce the pull of the magnetic field, allowing the higher resistance (and lower current) of the modulated coil to pull the needle off COLD sooner.

Bench testing to determine biasing resistance.

Initial testing proved successful, with the gauge capable of being adjusted to be accurate from the lower end of the range all the way up to maximum. It over-reads a little between 100-130F but is accurate at 180F and 230F. I decided knowing if the engine was too hot was more important to know if it was cold.

Resistance in place, heat-gun testing with sender unit.

Reassembled into the frame and tested the gauge again using the frame’s ground, as occurs in the car. Successful testing with good results.

Gauge mounted in dash.

I turned my attention to the paint on the dash, which was scratched and thin in places from years of polish and being handled. I started by stripping all the gauges out and taking the old paint off with a brass brush.

Paint removal.

The dash was then masked up, painted, reassembled and tested.

Ready to reinstall, looking very tidy.