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TR4/4A TR4A wiper motor rebuild

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Scotsman

Scotsman

Jedi Hopeful
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I have a two speed 4A wiper motor with a broken commutator. One of the segments is loose, and the connection to the windings broken. One of the speeds works but not sure which.

- If the windings are still OK can the commutator be repaired, or am I faced with having to have a complete rebuild with new commutator and windings?
- If the segment can be fixed in place I might be able to live with one speed. Can this be done?
- Are there any other options I am not thinking of?
- Is there an outfit that anyone can recommend to repair it?

Thanks,

Richard
 
Richard,

A quick check of a copy of a Lucas parts list I have shows the same armature (743929) for the 2-speed DR3A motor as the single speed. ISTR an article in this forum saying that the second speed comes from adding an extra winding to the field coil, making a 'slow' speed from the usual sped of 'not fast enough'. DR3As were used in many LBCs, and the MGB's was mounted inside, protecting the motor for future use as spares for TRs...

Jeff
 
Jeff,

Thanks for your reply but the acronym's in your response made it hard for me to understand. If its the slow speed that is bad then I could live with it, but I think the biggest issue is that one of the segments in the commutator is loose. It springs out from the shaft and I expect is the cause of the short as it probably caused a brush to catch on it and stopped the motor. Can the segment be fixed, or will the whole armature have to be rebuilt. If so i expect it will be v. expensive. :scared:

Your response suggest that the same armature was used in wiper motors for other cars. I don't have a Lucas parts list so have no way of knowing what motor I could salvage an appropriate armature from. Are you able to help out here?

Richard
 
Marv,

I need to have the field coil and armature checked out to be sure I am not throwing good money after bad. With that said I am interested in the armature and will get back to you on it. I bought the motor thinking I had a good deal, but now know why.

Richard
 
Richard,

You might be able to home-solder the segment back in, but the effort might also un-solder the ones next to it. Sounds like Marv can fix you up with a replacement though. Here is Alan's excellent BCF tech article to help you determine if your field coil is OK: https://www.britishcarforum.com/bcf/content.php?156-Lucas-DR3A-Two-Speed-Wiper-motors. A working TR4A 2-speed wiper is good for cool-points if nothing else.

Jeff
 
Last edited:
Jeff, I went with your suggestion and was able to find a lucas parts manual that showed the same armature was used in a variety of different motors. With that said I was able to salvage one from a Lucas motor of unknown origin.

Thanks
 
Great! You'll be able to clean out the gunk & put in fresh grease. Be sure to note the order of the parts so you can re-assemble it correctly. Is the 2-speed for your 3A?

Jeff
 
No, a 4A project car that came almost complete and assembled. I am going to post another Q reg the 4A front suspension strengthening kits. If you have an answer let me know
 
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