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Rebuilding a Wiper Motor

Moss Motors
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Brian Oklahoma Brian Plotkin
Edmond, 73012, USA   USA
1968 Triumph TR250 "Kevin"
I know there is an existing subject on Wiper Motors, but this is a little different. My wipers only work on Low Speed and won't park. I have a Lucas part number 54701383A gear assembly on a 1968 TR250. I don't know what the part number is for the motor. It is rectangular. Where can you find the motor part number? Is this gear assembly and motor correct for the car? - see attached photos.

I used Dan Masters troubleshooting to determine both of my problems are due to the motor. Dan's book also indicates that the TR250 motor is built differently from a TR6 motor. Can you get parts for TR250 wiper motors? If so, where?

What needs to be replaced inside of the motor (likely culprits)?

Is there a better description of the inside of the motor than the one in Dan's book?

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IMG_20170522_195942038.jpg

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Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
On my TR250, I sometimes have to cycle my wiper switch several times to get it to go from slow to fast speed. That's usually a sign that the switch needs to be take apart and the contacts need to be shined up.
Explain a little more on your parking situation, you mean it doesn't park where you want it to? Or it just keeps going and never parks until you turn it off?

mgruber921 Avatar
mgruber921 Marvin Gruber
Florence, Alabama, USA   USA
TR4a wipers are the same motor. TR 3 and 4 have some of the same parts or can used as subsitute motors.Only one speed on the 3 motors but better than nothing.
Marv

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Fictioneer Avatar
Fictioneer Doug Hirt
Colorado Springs, CO, USA   USA
Your motor has an extra winding, which allows it to run in two speed mode. Have you examined the windings to make sure they are intact? It sounds like it might be a switch problem. These Lucas 2 speed motors are wired counter-intuitively.

Also, check that the ground wire is not broken. That black wire screwed to the wiper body is essential for the motor to park.



"Mr. Filby, do you think he'll ever return?"
"One cannot choose but wonder. You see . . . he has all the time in the world!"



Edited 1 time(s). Last edit at 2017-05-23 09:06 AM by Fictioneer.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
The motor part number is in your second photo, 75568B. Appears to be correct for a TR250. The May 1968 date code makes it seem likely to be the original (assuming you have a fairly late TR250).

However, all of the internal parts interchange between other DR3A motors, so it's always possible that someone has rebuilt yours using the wrong parts.

About the only thing that could cause the motor to work on low but not on high would be an open circuit in the resistance wire inside the motor. That would also keep it from parking (the park switch effectively runs the motor on high). Probably a fairly easy repair, so my next step would be to open up the motor and see if the resistor can be repaired. You probably can't solder to the resistance wire, but you can make an adequate splice using the crimp barrel part of a small crimp terminal. Fold the wire back on itself so it makes two passes through the crimp for a better grip.

Or, if you don't care about high speed and just want it to park, installing a jumper between the two wires would probably make it park again. You could even do that as a test, to make sure the park switch and it's ground, etc. are good.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

sagreenwoo Stuart Greenwood
San Diego, California, USA   USA
I had the same problem with my TR250 wiper motor in that it only ran on high speed. It turned out to be the switch.
However please read the attached file which describes how the TR250 two speed motor works.
With a little bit of rewiring you can replace the motor with one from a TR6 or the Roadster factory will rebuild your original motor

Stuart


Attachments:
two-speed.pdf    292.1 KB

Brian Oklahoma Brian Plotkin
Edmond, 73012, USA   USA
1968 Triumph TR250 "Kevin"
I pulled the motor out and opened it up. The brown wire (the wire between the parking switch and the motor) had a gouge out of its insulation. It looked like it had been that way for quite some time. It may have even been originally built that way. Also, there was a lot of goop (some sort of brown, thick grease that is thicker than vaseline) all over the grounding plate and the park switch contact. I suspect there was enough of this to prevent the park switch from contacting the grounding plate. I believe one of those two things prevented the park function from working. Neither of these two things would cause the high speed not to work.

The rest of the wiring looked fine. They tested fine with my multimeter. I'm not sure what is causing the high speed not to work. I think I'd like to fix the park switch and put the motor back in place. I'm going to desolder the brown wire and replace it with a new wire.

Questions - what is that that thick grease - does anyone know? How much of it should be on the gears? Should any of it be on the grounding plate and park switch?

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TR250Guy Avatar
TR250Guy Tim Moore
Dayton, Ohio, USA   USA
1968 Triumph TR250 "TRminator"
I have read that the grease used in these wipers was a lead based grease. Might want to wear rubber gloves when handling it.



1968 TR250 "TRminator"
Owned since 1980
Frame off rotisserie restoration completed in 11-2014 by myself and my brother

Brian Oklahoma Brian Plotkin
Edmond, 73012, USA   USA
1968 Triumph TR250 "Kevin"
Ok. Good to know. I'll be careful around it.

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