Slammin' Headlights

Slow day today, so I decided try and figure out why my headlights go up fine, but slam on the way down. I can tell they have been worked on before because the crank arms are not stock. The crank arms are all metal and in good shape.

Tore apart the motors, and found the rollers are not oem either, and are no longer round, they are sorta triangular in shape. My guess is they have been pressed into this shape over time, creating slack between the plastic gear and axle. Also, there was no grease on the rollers or anywhere in the housing for that matter, which may be the root cause of the problem.

I have already ordered parts to rebuild. I have seen pics of the oem rollers disintegrating, but not of this problem. Has anyone else seen this?

rogold,

No, haven't seen this one but Barney has a collection of pics showing various "fixes" people have used over the years.

Perform a search on this forum or maybe Barney will see this and post a link.

John F.

Those look like my early rollers....... while they deform, they never seem to break and turn to powder. I used 1/2 plumbing line for the outside and the inside is filled with urethane. The deformation gives a good idea of the pressure and torque the rollers see. I stopped making them for several reasons...I started with rods of tubing about 18 inches long, filled them with urethane (which often trapped bubbles and that section of the tube was scrap. Next the outside of the 1/2 inch tubing needed to be reduced to about .480 which I did with a belt sanding fixture which took time, and finally they were cut to length.

The car probably has my steel bellcranks which do a great job even if they don't look like the originals.

If you pay the shipping I will send you new OEM type rollers

Thanks for the offer Barney, I was just interested if the rollers should have been greased. I have read elsewhere that they don't actually roll, so not sure if grease would help prevent the distortion. I tore apart some motors I got from UPullIt and found metal rollers. So I ordered enough parts to rebuild both sets so I will have good motors for my current car, and the elusive Reatta convertible in my future.

Thanks for the offer Barney, I was just interested if the rollers should have been greased. I have read elsewhere that they don't actually roll, so not sure if grease would help prevent the distortion. I tore apart some motors I got from UPullIt and found metal rollers. So I ordered enough parts to rebuild both sets so I will have good motors for my current car, and the elusive Reatta convertible in my future.

As you say, the rollers don't really roll. So the distortion doesn't hurt anything.

On lubing the gear, here is one of the first threads I started when joining this forum five years ago: http://forums.aaca.org/f116/headlight-motor-gear-lube-269754.html

Thanks wws, that link answered my question.

One other item that is seldom mentioned is the end play of the motor shaft which also has a direct effect on the rotating shaft freeplay. This is adjustable with the locknut and screw on the inside end of the motor. There should be a small amount of play when you push-pull on the manual knob, but just enough to allow for expansion when warm.

Delrin has never done me wrong and I have rebuilt many Fiero headlight motors, which share the same innards. ( but not the same housings). I have never seen Delrin get deformed . RodneyDickman.com sells rebuild kits for them and his stuff is quality. On another note, maybe if you using a thicker grease (I use Mobil 1 synthetic) will slow down the motor action some ? But to be honest, I soooo agree with you on the slamming action. I have never seen a car with such violent headlight door action as the Reatta.

I rebuilt mine a few years ago. I was surprised at how fast they go up and down. I agree down is a bit faster than up. In The past my Corvette lights didn't seem to go near as fast. I'm comfortable with the action on the Reatta lights. I just made sure everything was adjusted properly and I wouldn't necessarily call it violent but it is really quick!

I would describe the way my headlights lower as slightly violent. There is a clunk.

The design of the headlight slows the movement at each end. The attached sketch hopefully will show this movement. On the left is the arc of the bellcrank, which is transferred to linear movement on the right.

at each end (open and closed) the bellcrank arc slows the movement. Also it goes past center to "lock" the arm in both the open and closed position.

The arm only needs 180 degrees of movement to fully open or close the headlight door. I marked the arc in 20 degree steps but note that the other end spacing is wide (long) in the middle and short on the ends.

The headlight doors will slam down when there is excessive sloop in the system caused by either the bellcrank being worn or the rollers turning to powder.

A bit of trivia or another "FWIW" - working with the manual control knob, it takes 53 revolutions of the motor shaft to perform a headlight open or close function.

Now, if we just had a RPM on the motor, we could calculate what I now call a "nano second"!

I seem to recall that the Reatta motor is considered to have more torque than, say, the Fiero.

Kingsley