wiper motor park has stopped working

[steve w]

Hello all

 

While out in the rain the other day the self park stopped working on the 2 speed dr3a wiper motor.As I intend to use the car up until about mid Jan 2014 I don't won't to take the motor apart yet to investigate.I have checked the earth from the motor & all looks good. I am thinking its a problem with the little brass park arm. Any ideas?

Also can you still buy the brass park connector arm & if so where from?

 

Thanks Steve.

Edited November 11, 2013 by steve w

[Steve R]

It's a bit difficult to say what the cause may be if you don't want to take it apart, probably the brass wiper thing, or bad connection on the top, daft to get parts before knowing the cause, it's only a ten minute job.

Steve

 

PS. I know......some full restorations have started out as ten minute jobs

[AlanT]

Steve Hunt has all the bits for these.

 

http://www.ebay.co.uk/itm/LUCAS-DR2-DR3-DR3A-6W-6WA-WIPER-MOTOR-BRUSH-SET-7APC-/271314518871

 

Here are photos of the mechanism.

 

http://flickr.com/gp/90670218@N04/6948M3/

 

You probably only need to clean the contact disc and finger

[RogerH]

Hi SteveW,

you say you have checked the 'earth' connection - however there are two earths.

 

One goes through the two position switch.

The other , when the switch is in the off position, the parking earth goes through the red wire coming out of the top of the motor.

If these are OK then you will need to lift the top off - 5 minute job (not including the respray).

You may see that the track has worn through or things are in pieces. You can make a relacement track using single sided PCB and a bit of etching.

 

Roger

[AlanT]

I've had dozens of these apart, some going back to early 1960, never seen a brass disc that could not be used atfer a but of polishing up.

 

The contact between the the spring finger and shaft does not have much holding it just a spring clip.

[steve w]

Update

 

Hi guys thanks for your inputs. I have this morning taken out the motor cleaned up the the brass bits double checked both the earth connections on the switch & from the motor. (have not taken the armature cover off to check the earth connection in the motor but it seems tight).

But still not parking the wipers!

Whats the next step?

[RogerH]

Hi Steve,

the self park works by having the body of the wiper motor earthed through the brass wiper arm - copper track - wire that comes out of the centre of the plate and then earth on the body.

 

Is the earth on the car body where the wire would normally fit a very good earth?

Have you done a continuity check between the copper track and earth.

Is the brass arm earthed (good mechanical contact) to the internals.

 

Roger

[TorontoTim]

Conversely, during a recent 2-hour drive of off/on rain my wiper motor suddenly started parking perfectly: after 3 years of ownership when it has never worked once (didn't really annoy me too much, tbh).

 

Nope, don't understand that either!

[AlanT]

It would be quite easy for a poor contact to develop between the outside where the wire is soldered on and the brass disc inside.

 

I regularly re-rivet these when the resistance measures too high for my liking.

 

You could of course just have a break inside the red wire.

 

Just get a length of wire. Connect one end to the chassis. Turn on the ignition but dont switch on the wiper.

 

Touch the wire on the contact on the cap. Motor should run. Tell us all what happens.

Edited November 13, 2013 by AlanT

[steve w]

Hi Alan

Yes the motor did work when I did that.

[AlanT]

OK so the parking contact is not connecting the red-wire to chassis.

 

Since the motor sits on rubber bushes there need to be a wire, usually black from the motor case to the chassis.

 

Take the cap off and connect the wire to the brass disc. The motors run fine with no cap fiited.

[steve w]

Now sorted!!

 

Thanks to you guys & especially Alan T.

There was a electrical contact to the top of the cap but not from the inside (brass disc).Fitted a spare one I had with some old bits & now works fine.

Thanks again.

[AlanT]

Thanks for the update.

 

Quite a common failure mode. Mostly I re-rivet these.