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Rebuilding a wiper motor

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A well known register member passed a DR3A wiper motor to me recently.

It's got a 130 degree gear-wheel and came from a TR3A most likely.


It ran OK, but took more current than they should do, indicating it was a bit stiff.

It always amazes me how well these have stood up and I've yet to see one that is beyond repair.


But there are a couple of common failures and so here I dismantle this and show how to restore and improve these.


It came looking like this:




There is a bit more corrosion underneath than usual but this is insignificant.


Four screws hold the top-plate, one missing but I've got new ones.

Slip off the Horseshoe clip and C-clip, don't loose the tiny thin shim from the crank-pin.



This is a carbon-braush set, in good order, note the orientation of the "grooves".



The 130 degree gear, arm and cone-washer




Store the armature carefully to prevent breaking any wires.

If the carbon brushes wear down the two arms will cut grooves into the copper

I can "skim" these but this one is good. The black ring is normal.



This shows one of the common problems


The arm is bent up. Happens if you try to remove connection to the wire-rack without releasing the Horseshoe-clip.


The arm will scrape on the cover and the wire-rack won't go smoothly into its tube.

You can do without this extra friction.


It takes a few wiggles to get the big self-taps out of the pole-piece.

Go easy they could break off and this would be awkward to fix.



After 1 hour in Caustic-soda. Wear protection!



Edited by AlanT
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Very impressive Alan. I have had three wiper motors stashed away for about 35 years waiting to be rebuilt when I get a round tuit.


Wiper motor (DR2 460 V67 - Lucas with Lucar terminals, includes rack) - painted green
Wiper motor (DR2 1263 - Lucas with screw terminals, includes rack and mounting studs) - painted grey
Wiper motor (DR3A 54071382 75568A - Lucas with 3-wire mini-loom, includes rack) - painted grey, stripped, some parts missing

I've been retired since 2007 and still haven't got up the nerve or found the time to tackle them. Maybe this year...

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When 4VC went back on the road in 1993, the wipers were struggling, so I removed the motor to find that:

- brushes were almost worn out (but armature not scored)

- grease was almost solid.


I cleaned everything thoroughly, fitted new brushes and filled the gear compartment with Castrol LM grease - I know this is not waterproof, but it is less viscous than whatever Lucas used and water shouldn't reach the motor.


The 2-speed wipers have worked satisfactorily ever since - well, as best they can with the very floppy connection from motor to drive spindles! Even rotating each drive spindle and the rack (within its sleeve) 180 degrees made little improvement to floppiness, but the wipers cope and did so for the 9 hours I spent trying - and failing - to get to Malvern for the 2007 International! The important thing is to ensure the screen is wet before using the wipers, which is easy with the crude but effective and economical manual squirter, allowing the jets to be directed where required by adjusting one's thumb pressure.


Ian Cornish

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Hi Alan

Excellent - is this the first installment - and will you be enhancing the performance (quicker, 2 speed....?) as per your earlier articles?



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The work shown took about 1 hour.


These are the only tools used:



I have had that red-handled 4BA driver for over 50 years!


I like this grease:


Steel in bronze running slow wants almost no lubricant, The main job of the grease is keeping out water.


Could easily set up for two speed but this is 130 not 120 degrees so the right switch and wire would need to be added.


I have made some FAST DR2s thanks to 5 EKT.


Will post more when the top-plate comes back from plating.


I am planning to make a few 115 degree wheels for use on 4/4A. A 6 uses 115 degrees.

This means you can have a bit of wear in the boxes and the wipers wont drop off the edges.

I have some 150 wheels that don't have much use.

Edited by AlanT
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I eventually made a mandrel to locate the pole piece squarely back in the casing. I know you can get it fairly close most times but I have had a devil of a time with a few that just would not go in squarely and allow the armature to spin freely without poling - (even after slackening screws and clouting the thing with a hide mallet whilst running)


And yes, I have scrapped a couple of pole pieces by breaking a seized screw off in it.


I always imagined that if I used 150 degree gear in a DR3 square bodied wiper motor you could run TR6 wheel boxes. (best bit about TR6 wheel boxes is that they are still genuine Lucas product. - are they not also fitted on current Land Rover Defender?) The reason for using TR6 wheel boxes is that their driven gears are a bigger diameter than those on TR3A-5. Or have I got my mind in a twist?


I still have a couple of old unit single speed DR3A units from TR4 if any one needs a repairable core to work with. - GBP £ 15.00 plus whatever carriage.



Peter W


PS wipe the armature commutator with meths to remove any grease before refitting.

Edited by BlueTR3A-5EKT
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Hi Pete,

haven't clue what your talking about but regarding your twisted mind - you worked on aircraft thus you must be a little twisted :P





I was hoping that someone would jump in here and say - 'Rubbish' or 'Exactly what I have done' - Oh well back to the drawing board.



Peter W

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Well here is an offer.


Anyone who wants to fit TR6 wheel boxes in a 4 and wants a wheel to go in a DR3,

just needs to tell me the stoke made at the end of the cable.


I cant see any really good way to find this without actually fitting them.


I can then work out what wheel to use and make one if there isn't one.

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So now I fix up the self-parker cap.


You can see the two holes for the rivets and another small hole through the contact assembly for alignment purposes.

This allows water to get between the cap and disc and even leak into the self-parker.



I dismantle these so as to allow the plater to do a good job but it also allows me to fix this leak.

Also corroded rivets that don't make electrical contact is a common "mystery" problem.


Rivetting is tricky but especially so with these tiny 3/32 rivets and five layers to hold together.

These rivets are IRON not steel. Makes them much easier to form over.



Its not enough to just fix it. The rivets must not touch the cap or there will be a short-circuit. This is quite tricky because the bits move about as you hit the rivet. I like to solve two problems at once and so I seal all the parts using Polyurethane sealant. This makes the rivetting operation much easier.


You can see this here where the parts stay in place even though not yet rivetted.




A key thing when rivetting is to have exactly the right amount left to hit. A bit less than the diameter of the rivet should be sticking out.



Even then this can easily go wrong so it's a relief when the rivets form over and make a tight joint.

And even more when there is "through-contact" and no "short to the cap".


Edited by AlanT
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This is what you want Alan to hold the bits together as you peen the rivet. An Avdel skin peg in 3/32 format.

If you want one I will put it in the post to you FOC.


Peter W



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Fit a rivet in one hole. Now Fit the skin peg in the other - start with the moving leg fully extended to get it in the hole. See the LH Pic. Push fully in till it stops. Tighten the nut and the threaded shaft on the left is drawn up pulling the many skins together. The moving shaft and the fixed pin now fill the hole as they are both D cross section, and the step on the threaded pin pulls up the skin. Once the thing is pulled tight like pic on RH, swage your first rivet.


Pm me your address if you want one.



Peter W

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Most TR electrical problems are down to simple connection problems.

Contacts are often made of steel and plated rather than being brass.


Here are the wiper spade-terminals and the two semi-circles that must contact the brush-arms.



These will work but would benefit from cleaning.


Files, scalpels and other rough stuff get used for this and will mostly remove too much plating.

You want Scotch-Brite pads. Here is the result of a few minutes with a tiny scrap of this:


Edited by AlanT
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  • 3 weeks later...

If you have not done so for a while, it would pay to take the cap of the wiper-motor and check the carbon-brushes.

This is should be a 5-minute job. Ask if you don't know how to do it!


If they wear down too far:



then they cut into the copper bars on the commutator:



This didn't come from the motor shown earlier in this topic which is in good shape.

It came from another ebay item and shows your biggest risk if you buy these unreconditioned.


These copper bars are too thin to be restored by skimming in a lathe.

Edited by AlanT
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  • 1 month later...

There are often questions about adjusting the self-parking.

This is all controlled by the position of the cap.


Here I have rotated the cap, so as to drive the crank to the exact position where it has started to lift the wipers, from the bottom right-hand side of the screen.



And here I have rotated the cap so as to drive the crank so its lifting the wipers from the bottom left-hand side of the screen.



This assumes of course that you put the wipers on the correct position on the splines.

Set the cap before you mount the wipers to avoid paintwork accidents.


Note that I did not use the cover-plate and made a temporary joint with the red-wire. Then I held the cap and just watched where the crank stopped.

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I have two-speed modified DR2s that behave like the TR4A two-speed.




I have unused Lucas "B90" reconditioned units fitted with replated cover and cap.


Which kind of cap do you like?



DR2's are likely to burn-out if you jam the blades or they get frozen.

These thermal cut-outs were made especially for the DR2 to solve this problem.


Edited by AlanT
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  • 1 year later...
  • 4 years later...

Alan, hoping you can help. I am restoring a lotus with a two speed DR3A. I can only get the motor to run on one speed and return on a slower speed to park. 

I have 3 wires coming out the casing Green, yellow and red. My understanding is green constant live and other two casing to earth should give the slow speed?


would you know why I can only get one speed or how to test to determine.


kind Regards, Steven

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