TR2/3/3A Wiper Motor Parking Question

[SteveBones]

Hello,

First I will start with some background. This is a newer for me 1958 TR3A. I have owned the car for close to a year and have been working on a number of things. The way I would describe it, the car is in great condition, was repainted some time ago, and I expect during reassembly, there was not an experience TR3 person involved in the process. I have found a number of things reassembled incorrectly and not working correctly. I am now working on the wiper motor. It was working when removed, but the park location was not working and the wipers were rotationing 4 or more inches past the windshield frame. I decided to remove the wiper to clean up and repaint the center section wrinkle black as original.

Prior to removing, I tried resetting the park unsuccessfully. I do not even recall that the park was working at all. So I really need to take a start from the beginning approach to setting up the wiper motor and park position correctly. Please see below for questions I have and also please add key items I have missed:

1) With the wiper motor gear cover removed, their is what looks like a brass contact (see picture). What is the correct positioning for this contact? And what is the reference for positioning? Do I use the gear cover raised spot as the reference (see picture)?

2) Regarding the wiper motor gear cover, I noticed the small "bump" pointing close to where the wiper shaft hooks up in some photos on some TR3A pictures on the internet and about 180 degrees the other direction in others. Is there a good starting point for positioning this gear cover "bump" when I reassemble the wiper motor?

3) Another issue is with a ground wire. As mentioned my TR3A is a 1958. I only noticed the two green wires connected to the wiper motor. I have seen pictures of TR3A's that also include a ground wire connected to the third screw to the wiper side cover plate. I recall that this might also be needed in order for park to work (please confirm). My TR3A did not have this black wire connected. Is this black ground wire separate from the wiring harness? Meaning can this be added? If it can be added, is one end connected to the screw on the side over plate and the other end to one of the wiper motor bolts on the car body?

Thanks in advance for your help in correctly setting up my wiper motor.

 

[TR3driver]

The moving contact should fit into the slot in the post; IIRC it only fits one way. Normally it is held there by a clip, not the nut visible in your photos.

Sorry, I never paid any attention to the bump. If you look under the cover, you can see the other contact. The motor will continue to run when the two contacts touch, so position the trailing edge of that contact (as the motor turns) where you want the motor to park. Obviously you need the wiper arms positioned correctly first, so they don't run off the windshield frame. It's best to wet the glass while checking the motion, as mine move farther when the glass is wet.

The ground wire is needed for the park function. Mine is just a short length of black wire, with a spade terminal for the screw in the housing and a ring terminal for one of the mounting bolts to the body.

There should be one or two solid green wires, and a black wire with a green tracer. Make sure the green wires go to terminal 2, or you'll have a short through the park switch (which grounds terminal 1 to make the motor run).

 

[SteveBones]

Thank you Randall. The information you provided is clear and understood. Now it is time to get this all back installed and running as intended.

The moving contact should fit into the slot in the post; IIRC it only fits one way. Normally it is held there by a clip, not the nut visible in your photos.


(Response) - thanks for the info regarding the clip. Should be able to find one at the local ACE Hardware store. One additional question regarding the nut, should this be removed? That is what I understood from your response but wanted to confirm.


Sorry, I never paid any attention to the bump. If you look under the cover, you can see the other contact. The motor will continue to run when the two contacts touch, so position the trailing edge of that contact (as the motor turns) where you want the motor to park. Obviously you need the wiper arms positioned correctly first, so they don't run off the windshield frame. It's best to wet the glass while checking the motion, as mine move farther when the glass is wet.

(Response II) Makes more sense to me as you describe (looking under the cover to see the contact area). Also great suggestion to wet the glass while checking.

The ground wire is needed for the park function. Mine is just a short length of black wire, with a spade terminal for the screw in the housing and a ring terminal for one of the mounting bolts to the body.

(Response III) Thanks for confirming regarding the black wire. My other TR3A was post 60K serial number and had the black ground wire as part of the wiring harness which is different than my 1958 TR3A.

There should be one or two solid green wires, and a black wire with a green tracer. Make sure the green wires go to terminal 2, or you'll have a short through the park switch (which grounds terminal 1 to make the motor run).

(Response IV) Thanks for the proper green and black wire with green tracer terminal connection arrangement. I should have taken pictures before removing but did not. Your explanation will save me a bunch of time vs trying to figure it out via the TR3 wiring diagram.

 

[TR3driver]

If the nut works, I would probably leave it alone. The process of cutting threads for it may have damaged the groove where the clip goes. And if I recall correctly, the clip is somewhat different than a standard E-clip. I don't know if the difference is important or not.

Here's a wiring diagram that should be pretty close for your car (except for the gauge positions in the instrument panel). I marked it up for LHD from the 4th edition of the owner's manual (which is also a good thing to have). (after you click on the thumbnail, look for the magnifying glass to get a full size view)


BTW, you might want to add your 'new' car to your signature.

 

[SteveBones]

Thanks again Randall. I will make sure to do all that you recommend. You are right in that the nut looks to have damaged the groove where the clip goes. I now need to go and meet my wife at school. I will update later.

 

[SteveBones]

The moving contact should fit into the slot in the post; IIRC it only fits one way. Normally it is held there by a clip, not the nut visible in your photos.

(Response - Update) I have an update regarding the moving contact. The section of the moving contact that fits into the slot is gone. Not sure if it was broken off intentionally or some other reason. I noticed there is a clip on ebay that is advertised for a few dollars. Without using a clip, the potential issue is that if I tighten the nut, it puts pressure on the gear shaft which creates resistance when rotating. I might need to find a clip and use it via a layered approach.....meaning clip on bottom, followed by moving contact, and finally tightening the nut. It is a bummer that the clip and contact are not available as replacements. I will be busy with a couple of items and will update on this in a day or two. Thanks again for the help.

 

[TR3driver]

Sounds like time to be looking for another motor, or at least the pieces (gear assembly & contact) from one. I kind of doubt that you can get enough friction between a clip & the nut to keep the contact from turning in use. Not right away, but at some point with the normal heating and cooling that goes on.

OTOH, maybe self-parking isn't the most important thing. After all, earlier TRs didn't have it even when new.

 

[SteveBones]

Sounds like time to be looking for another motor, or at least the pieces (gear assembly & contact) from one. I kind of doubt that you can get enough friction between a clip & the nut to keep the contact from turning in use. Not right away, but at some point with the normal heating and cooling that goes on.

OTOH, maybe self-parking isn't the most important thing. After all, earlier TRs didn't have it even when new.

(Response) - You offer a much better solution than the one I was considering. I will just live without the self parking "feature" and keep an eye out for another wiper motor for sometime later.

Thanks again Randall, I likely would have put too much time trying to fix.

 

[SteveBones]

Well I finished with the TR3A wiper motor installation and something weird happened. Instead of this being bad, it is actually a really good outcome.

Everything is working including the park. Even though the middle strip on the contact is gone, there is still enough left to keep the contact from rotating. Might not last, but I have no real need for extended usage.

So for a quick recap. Before taking this on, the wiper would rotate quite a bit past the wind shield frame and the park was not working. So basically could not use.

Thanks again Randall for going through all the steps for correcting these set up issues. My previous experience with TR wiper motors involved reinstalling everything the same way since the set up was correct. This time is was more involved because the gear was inserted incorrectly, the contact was broken, the contact clip was missing and replaced with a nut, and the ground wire was missing.

I also replaced the red wire as the original wire insulation was in bad shape. So for now the wiper motor is working good as new and looks good too after removing all spray paint, stripping and repainting the wiper motor bracket, and installing new rubber on the wiper motor base bracket.

Randall, thanks again for all the help!