Lucas DR1 rebuilt and test failure

Saloons
1

Dear friends,

I am now spending 3 weeks to make a DR1 wiper motor of my Mk VII work again.

I have cleaned it completely (every piece looks new!) and rewired it, replaced the thermo switch by a new one.

I have tested that I get 8 ohm between 5 and 4 and less than 1 between 1 and 2. I have tested it with the switch and without. connecting 1 and 4 to ground and 2 and 5 hot. It turns free and tested each segment of the main rod. Sometimes it starts for 2 sec and then stops again. You see that connecting it to battery you get a small spark.

The bushes seems to give good contact although they are not new.

Any idea what other tests I could run?

Desperate???

2

in general, is the arcing between the brush ends and commutator segments?

I would be inclined to check these very carefully, and polish them for good contact.

it is possible for the commutator segments to wear, so the examination should be thorough

3

I have a different motor, the DL3, so can’t offer any commentary on your wiring. However mine had similar symptoms. The commutator required a thorough cleaning, esp between the segments which were choked with carbon. Most importantly though, although the brushes looked like they had plenty of meat left, they apparently didn’t have enough, because on this motor the tension spring runs between the two brush arms. So as they wear they move closer together and the spring tension gets weaker. I bought a new set on Ebay complete with new spring and insulator tabs, and found that the new brushes were a lot taller which resulted in increased tension and more positive contact between the brushes and commutator.

4

Many thanks for the feedback.

I will try to find new bushes and clean the commutator ends even better.

5

I have given up on fixing mine. One day, when finances permit, i will buy a recon rather.

6

I have a fair few wiper motors on my Rovers, which I think are the same as on my S1 XKE: if anyone needs one, let me know, and Ill pull one and we can definitively determine if it’s the same.