Clunking Headlight(s) (Page 1/3)
Brent7088 AUG 05, 11:05 PM
When i lower my headlights (especially the driver side) it makes a clunking noise or a thud the moment I hit the switch. I removed the links and greased them but that wasn't the issue. Could this be a gear problem like worn or missing teeth?

Here's a 23 sec. video of it (please excuse the poor video quality). You can obviously tell my battery is weak from the speed of the light going up.

https://www.youtube.com/wat...cDA&feature=youtu.be
cvxjet AUG 06, 12:21 AM
The headlight motors have a gear with rubber bumpers that go between it and a spider bracket...the bumpers slowly disintegrate and then the motors develop the clunk- If you are confident of your mechanical abilities, Rodney Dickman makes a kit with an aluminum replacement gear and new bumpers, along with grease and screws to replace the rivets that hold the motor together- I just did mine- time consuming but straight forward. One of my gears was stripped....
Gall757 AUG 06, 11:04 AM
For future readers, this '86 Fiero has the first generation headlights. '87 and '88 are different.

[This message has been edited by Gall757 (edited 08-06-2019).]

Svenge AUG 06, 11:17 AM
I literally just fixed this on my car. Here's some pics of the process. The other guys already mentioned the cause. It's the rubber inside the "white" plastic gear which I replaced with a new black one containing new rubber bumpers.

https://imgur.com/gallery/D9zYoKE

-Svenge
Brent7088 AUG 06, 03:53 PM
cvxjet - thanks so much for the helpful tips.. yea I don't mind tearing into the motors. So far I have the light and the motor both out of the car. I noticed on ebay there is a gear kit that's either identical or similar to Rodney's but somewhat cheaper in $ -- not sure yet which one to go with:

https://www.ebay.com/itm/FI...1982-86/143344745855

Gall757 - appreciate the heads-up for other readers so that there's no mistake

Svenge - great pics you've posted and very helpful. Would it be best to put the motor in a vice and punch the rivets out with a hammer or to just drill them out? I imagine there would be less risk of damaging the housing with a drill. Also I'm assuming the plastic gear is typically the only one that needs replaced?
scottd AUG 06, 04:22 PM
Wait... my 86 is not supposed to make a clunking sound? I have a rebuild kit, just need to do it.
fierofool AUG 06, 04:53 PM
Brent, it would be best to drill the rivets out. Just use a bit that's large enough to break the flared part loose from the main body of the rivet. Then you can use a small punch to push the rivet out. Trying to drive a flared rivet out will break the case.

Something to be aware of is the rubber "D" seal at the top of the case. In Svenge's linked photos, note the brass "D" bushing at the very top of the motor. Just above it is the "D" seal. It fits into the case, not on top. You can tell when it's in the right place when the groove in the seal lines up with the groove in the case half. If you leave it on top of the case, the motor won't shut off completely when the headlights close.

Be sure to get all the old junk out of every tooth and cranny of the motor screw gear and the small metal gear. A dental pick and wire brush are invaluable. Pay attention to the direction the curled spring washer is installed on the small metal gear. The edges curl toward the case, not toward the gear.

I suggest you use a good high temp synthetic brake slider grease to lube the gears inside the motor. It won't harm plastic gears or bump stops. Also, I don't know what reseller you might be considering, but your replacement gear should use bump stops. Gears without bump stops can cause other non-replaceable parts to break.

Lubing the plastic bushings in the main headlight mechanism can be detrimental. Depending upon the lube, it can cause the bushings to crumble. A very light spray of silicone lubricant should be sufficient and cause no harm. Apply it with an aerosol can with a tube inserted in the nozzle.

Bumping can be eliminated after the motor repair by replacing the rubber bumpers in the ledge at the front of the headlight door opening. The Fiero Store sells them in sets.
Svenge AUG 06, 06:12 PM

quote
Originally posted by Brent7088:
...
Would it be best to put the motor in a vice and punch the rivets out with a hammer or to just drill them out? I imagine there would be less risk of damaging the housing with a drill. Also I'm assuming the plastic gear is typically the only one that needs replaced?



I bought the pair of kits here - yeah only the plastic one needs replacement:
https://www.fierostore.com/...%20%20PAIR&d=273&p=1

One of my plastic gears was definitely shot (several teeth completely missing), the other one actually was in pretty good shape, but i replaced it anyway.

The kit came with instructions that were actually pretty helpful, including the exact bit size to use (i think it was 1/8"... but don't quote me lol). I used a vice for some, and my foot for others.... but overall it was a pretty easy part of the job. Hardest part was probably getting the whole assembly out of the car, and also pounding the plastic gear out. The shaft is pressed into the external lever (pound job #1), and then the gear is retained by that "spider" looking flanged thing, which is also lightly swaged onto the shaft (pound job #2). Careful not to damage your shaft with all the pounding.
I watched these vids while doing the job... but this guy doesn't have the kit so he did a few things differently:
https://www.youtube.com/watch?v=1lUT_c-0vuk
https://www.youtube.com/watch?v=G_3hkwDIGRg
https://www.youtube.com/watch?v=C40OCRtazes
... you can probably find the rest.

Last thing I'll say... the kit doesn't come with new brushes for the limit switch assembly. One of mine was broken off. I decided not to fix it... risking the contact leaf wearing out over time. Maybe prepare for similar results.
fierofool AUG 06, 06:31 PM
To get the short lever off the end of the shaft, I support the whole motor by holding that lever with a pair of slip-joint pliers. Loosen the nut until about one-fourth to half the threads are showing in the nut. Hit the nut with a small hammer. The shaft is actually pretty mild steel and you can damage the threaded end if not careful.

The drill bit size is 1/8. You're correct. Sometimes the rivets will try to spin. I use the small slip-joint pliers with the lower jaw on the case edge and the upper jaw gripped against the head of the rivet to hold it while drilling the flare off the rivet.

Various combinations of deep well sockets and a small anvil with a hole can aid in removing the 4-legged drive plate and in reinstalling it. I have had tooling made to swage the drive plate back onto the shaft

[This message has been edited by fierofool (edited 08-06-2019).]

Brent7088 AUG 06, 11:34 PM
Fierofool and Svenge - thank so much for the helpful tips. I drilled out the rivets and removed the mounting bolts (what a mess inside!).

What should I do if when opening it further that I find out the plastic gear is in good shape (no worn or missing teeth) and the only thing needing replaced is the green plastic bumpers/cushions? Should I get the entire kit anyhow or just look for the bumpers and assembly screws alone?

[This message has been edited by Brent7088 (edited 08-06-2019).]