Reatta headlight motor

[Barney Eaton]

I recently received this headlight motor to rebuild. I wanted to share the picture with you as this motor has about everything wrong with it that can go bad.

(1) on the left the gear housing has 2 broken screws out of three that hold the side cover on. This motor came from Ohio and the frozen screws are typical of units from the rust belt, on cars that are driven in the winter.

(2) upper right show the fine plastic pieces that come out when you remove the shaft from the big white gear. The plastic rollers are just under 1/2 inch X 7/16 when new but the torque inside the motor often cracks them and the

action of raising and lowering the headlights grinds them into smaller and smaller pieces until you get dust.

(3) the bottom right part is the motor housing, you are looking into the big end, the picture is not clear, but one of the permanent magnets broke loose and shifted. This is a very rare failure. I did not try the motor before disassembly, but it is unlikely that it would run. I would guess this motor has either been underwater, or somehow has had water standing inside the motor housing. This rust the inside of the case and under the adhesive holding the magnet.

This can probably be salvaged by sand blasting the inside or some heavy sanding so new adhesive can get a grip.

With this motor, the customer sent the other side motor which someone had attempted to repair. One ear was broken where they tried to drill out a broken screw, and the other screw was drilled off center, down the side of the screw...pretty much destroying the motor housing.

[Jim]

It's not just the northern cars that the three screws won't come out. Two days ago I went to put rollers in a pair of motors that I took off a parts car I got in Atlanta GA and five of the six screws on the two motors were stuck.

The castings are diecast pot metal and the screws are steel so there is a chemical reaction and the screws corrode and stick.

If anyone has a way of loosening those stuck screws without breaking them off I would sure like to know how.

I have tried heat with my torches and two days ago I tried using my arc welder to try and pass a high current through the screw, hopefully loosening it, but no luck.

[Labrat]

Would there be any problem when rebuilding the housing to use studs instead of screws and secure the housing cover with nuts and a lock washer? Just wondering...

[Guest Mc_Reatta]

Would there be any problem when rebuilding the housing to use studs instead of screws and secure the housing cover with nuts and a lock washer? Just wondering...

You can just drill through and use a nut and bolt.

[Barney Eaton]

For those new to Reatta headlights..... drilling out the screws is not a simple task.

Except for some early 1988, where the holes were tapped, the supplier of the headlights started using "thread forming" screws early in 1988. The way they work, there is a pilot hole, and the screw makes it own threads. Since the screw makes its own thread, there is not clearance. Any small amount of corrosion locks the threads. The screws are 8-32 making the thread base pitch close to .120, which is pretty easy to twist off.

Like Jim noted, I have tried heat, pentrating oils, and impact in an attempt to loosen the corrosion. You must be somewhat careful with heat because the first thing you ruin is the gasket. Too much heat will melt the aluminum.

Just drilling them out and using a nut and bolt is over simplification. The screw is case hardned so that it will make it's own threads. If you use a standard high speed steel drill, after one screw, you throw away the drill or resharpen. Exotic drills work better but are harder to find and more expensive. In addition, you must somehow start the drill in the center of the broken screw, otherwise, the drill slides off into the soft material. Also note that trying to do this with a hand drill if futile.... you must have a drill press.

I buy solid carbide circuit board drill off Ebay. Carbide last a long time unless you chip or break them. If you break one off in the hole, now you have a real problem.

If I am lucky, I drill thru the broken screw. Then I step up in size, usually to .125 (1/8 in which is a standard, easy to obtain drill) and drill the hole out to that size. Sometimes the threads will start to peel away from the aluminum during this drilling. Next I run a 8-32 tap into the hole and it will usually remove the old/original threads of the screw and you are done.

However, if someone has been there before you or if you get slightly off center of the screw, you must drill the hole oversize and use a heli-coil thread insert, or if the hole is really large, I have found brass threaded inserts that salvage the hold.

[Guest Kingsley]

These days, seems like I find more siezed 8/32" screws than those that back out normally. I have a pretty good record on drilling and tapping as I use a countersink drill which has a 3/8" body then going to a drill point, length only 3/8" minimizing greatly the chance of drill bit wobble and, at the same time, leaving a hole that is ready to take the 8-32 tap. As most motor rebuilders do, I have a jig which ensures that the drill point makes contact at the proper point.

Seems like I am always short of the 8/32 machine screws with a technical ID of "indented head unslotted flanged hex machine screws" but finally ran across a source only today and just for the heck of it will try both black oxide and stainless.

Motors are certainly not a big deal but I always like to keep them as OE as possible thus the push for drill and retap as opposed to using a drill through approach. Certainly, to each his own and I find motors very forgiving of almost anything.

Had a call one day from someone who had rebuilt a motor and found his headlights our of sync when opening and closing. Polarity on one motor was reversed and he had, in the course of fastening the upper and lower housings together, had failed to align the tab that protrudes from the upper housing with the corresponding tab in the lower housing where the wiring connector exits. The headlights looked cute winking at one another but functionally a disaster!

[Barney Eaton]

Kingsley, never had a problem with headlight motor polarity, but have had antenna motors with the magnets installed wrong and the mast went up and down in reverse (down when on and up when off)

[padgett]

With the early Fiero motor it is easy, have seen it several times.