A Review of Replacement Headlamp Motor Bell Crank Arms for the Reatta


by Padgett, December 2011, links revised May 2012

One of the most common failures in the Reatta is in the motor and linkage that raises and lowers the headlamps.

While most worked well for the first few years, two decades out from the last manufacture, nearly all have experienced failure, either for the headlamp not to rise, to do a dance while rising, or to rise then drop. All are caused by the same the mechanical failure.

Some years ago I wrote an article on the repair of Fiero headlamps. While that covered part of the issue, decay of the rollers, the Reatta and the Fiero both have additional failure modes and each is different. While the Fiero would often strip the large nylon gear, instead the Reatta strips the inside of the pot metal crank assembly. When removed an oval original hole has become round. Since the shaft inside is smooth, it then simply spins instead of raising the headlamp.

Note: Whenever an unknown assembly is replaced, also replace the three rollers inside the motor. These have often decayed into powder. While the crank can be replaced in the car, unless you know the rollers are good, the extra time should be taken to replace the rollers also.

Also any time work is done on the headlamps, check the plastic upstop nut and retainer since compression of the retainer is what keep a headlamp from vibrating. Some of the kits below include these parts also.

Instructions on repair

Excellent instructions on the headlamp assembly removal and replacement of the crank assmbly assembly can be found at reattaowner.com and will not be repeated completely here.

Alternatives

Today there are multiple alternatives for repair ranging from unobtaiinable/expensive to inexpensive/DIY however the last requires some machining capability. Each has pros and cons I will discuss. All, except possibly the OEM, should outlast the car.

Original GM Crank Kit

The hardest to find today is going to be an OEM p/n 16510108 "Crank/Act Pkg" which includes both the crank and the lever arm. Just the crank was p/n 16507168. For a 400 point #1 car this may be worth while but they have been discontinued for some years. Nevertheless they still surface occasionally. The crank kit assembly comes with crank arm and the rubber bumper plus a new through bolt and nuts. (If buying a NOS unit make sure the two screws and nuts are there and the bag has no holes). Keep in mind that this is the same pot metal device that has already failed once on the car.


Photo by Padgett

Reatta Specialty Parts Retro Fit

The next choice is the RETRO-FIT Headlight Crank Arm and Parts Kit from Reatta Specialty Parts, LLC. This is an original crank core that has had a hexagonal alloy steel insert pressed into a machined cavity in the crank. This insert is not visible when installed on the motor .


Image courtesy of Reatta Specialty Parts, LLC

This is part of a kit which includes the crank, crank arm, Delrin rollers, and a rubber impact bumper that maintains the original look even if the plastic covers over the area are removed for inspection.

In fact the only way to tell this is not original would be to disassemble the motor assembly and check for the steel insert.

Machined Cranks


Image courtesy of Reatta Parts West, labels by Padgett

The three remaining methods all have pro's and cons and represent a fit and function repair that is dissimilar in appearance to the factory unit but is not easily seen. For most it will not matter since the headlamp will raise and lower properly.

Barney Crank


Image by Padgett

This replacement crank is known as the "Barney Crank" and was the first replacement available. It replaces the clip holding the arm to the crank with a nylock nut on a threaded post. This has the advantage of making it easy to replace the arm in the car (this should only be done if the rollers are known to have been replaced). OTOH, while there is no question of strength and I have used several, the Barney crank is made of thinner material than those from the other vendors. This can create a mismatch between the crank arm and the housing which could shear the rubber stop.


Mismatch, note: rubber bumper has sheared off.
Image by Padgett

A headlamp with an arm that overrides the frame as in the photo may close completerly and then open back up slightly as the arm travels overcenter.

This should always be checked with a trial fit to the motor in the bucket. If there is a mismatch, the flange on the back of the crank can be bent slightly to fit. The end of the arm must be inside the housing since the housing acts as a limit for operation. Once properly aligned, I have had no problem with these units. OTOH this is te only replacement that may require this adjustment.

Reatta Specialty Parts New Design

Image courtesy of Reatta Specialty Parts, LLC

The second is also from Reatta Specialty Parts and is the "NEW DESIGN Headlight Motor Crank Arm Kit". This made of thicker material matching the original and includes the rubber bumper that slides over the flange and cushions impacts with the stops. A rubber cushion should be used with any crank arm replacement.

This is a very complete replacement that includes the crank arm, rollers, lubricant, nuts and bolts, and plastic stop. This also includes three washers/spacers to align the crank arm bar with the headlamp bucket recess if needed.

Con is the same as the original, the special clip type attachment that is relatively easy to attach on the bench, but also easy to drop in the car so it is best to attach the arm on the workbench at a cost of being slightly more difficult to attach the motor into the bucket (note: the New Design crank comes with th crank arm assembled so unless disassembled for some reason, this is not a issue.)

Image by Padgett


Reatta Parts West Crank Kit


Reatta Parts West Crank Kit
Image courtesy of Reatta Parts West

The third crank arm is from Reatta Parts West and is very similar to the previous. It is fitted with a "hitch pin" clip that is easier to attach than the original. In the car it can be installed using needle nosed pliers.

The bar is as thick as the original kit and requires no additional modification for use.The test device aligned properly out of the box, and has worked well since.

This includes the crank arm with pin, three rollers, a new nut with additional securing surface, and two plastic upstop screw retainers (both round and square as both have been seen on Reattas). The nylon screw is available from any local FLAPS.

           
Stock (left) and new nut               New retainers.              
Images courtesy of Reatta Parts West

DIY

The last method is DIY and requires some machining. Drilling the hole itself is definately a matter for a drill press and vice since there is not much of a target to hit (area is .350" thick less a .060" chamfer on the bottom) and the surface is not level so need a very slow feed and a good dimple.

For this, 10-24x3/8" stainless set screws from Home Depot or Lowes (two were under a dollar). This is the shortest to use, 1/2" would work also. Creation of the tapped hole requires use of a #26 (.1470") drill. Some sources say to use a #25 but I prefer it a little tighter. Neither is close to any inch size.

If using a vice you need to drill very slowly and avoid any drill wobble or offset caused by the slanting surface (a milling machine is preferred but may be done by hand if careful). Once the hole is drilled, tapping and running in the setscrew is easy.

This method requires removal of the bucket or, at least the motor assembly since the setscrew can only be tightened out of the car. Locktite on the threads might be advisable since it would not be expected to be removed.

Note: the rubber bumper may be replaced with a 3/4" piece of 3/8" rubber fuel injection line, standard hose will probably not be strong enough. However this would be evident to a judge looking for it.


Image by Padgett

Barney's 1999 DIY

A decade ago Barney also suggested a method that would add a steel brace to an original worn out crank. This method is listed with drawings at Reatta.Net. I have not tried this method but see nothing wrong with it. The description includes quite a bit of information on disassembly of the motor drive unit and should be read before attempting any repair particularly replacement of the rollers.

Conclusion

With proper care in fitting, all of the above methods will work properly and with the possible exception of the OEM crank should not be expected to fail for the life of the car. The major differences are:
1) price
2) appearance
3) completeness of the kit (many have options)
4) ease of installation

Which is the proper choice is dependant on the individual's needs. All that I have tried have worked for me.

Note: this review is intended to be for the crank arm assemblies themselves. While several vendors include the plastic rollers and/or upstop screw and retainer as mentioned these are beyond the scope of this article but should be considered during any rebuild.

Padgett, Orlando, December 2011 & May 2012

Vendors

Reatta Specialty Parts

Reatta Parts West

Barney Eaton

Weasle words: The entire contents of this web page with the exception of photographs obtained from vendors with permission are personal observations made of actual parts and descriptions of parts over a period of years. Any errors are my own and will be corrected when pointed out.

Availability of parts from vendors is subject to change and the vendor should be contacted prior to purchase. OEM parts may or may not be available.

Original content is copyright (C) by Padgett 2011, 2012