Wiper Motor Repair Guide

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Re: Wiper Motor Repair Guide

Post by scimjim » Sun Jan 08, 2012 10:00 pm

we've already agreed that Tony - W/G for park. Bob has also established that he never has +12v at the W/G - hence my question.


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Re: Wiper Motor Repair Guide

Post by Taggers » Mon Jan 09, 2012 11:13 am

Incidentally there is nothing inside the motor that would make it do this other than (possibly & I haven't thought it through) an electrical problem. Certainly not the brushes or armature (which together with some magnets comprise the motor).
Thanks Tony, obvious, when you think about it.

I can't think how that would affect the speeds, but thinking about it objectively, that's more likely to be a misreplaced wire (not that I would do that, obv), so I will do an extra careful check.

I'm fairly sure the wiring is not too far out, because it works sometimes. So I figure the big problem is likely to be mechanical, the ramp on the gear wheel not pushing the the switch enough to work it.

It occurs to me that there are three possible causes for this. One is the switch being incorrectly mounted on the motor. They are a fiddle (honestly, Lucas, what's wrong with screws?) but you don't have many options. I will check, but I reckon it's fine.

The second is that the gear is somehow too far from the back of the gearbox. I don't see how this could happen without other symptoms, and this is something that came on before I'd had a chance to take it apart and put it back together wrong (the usual reason for faults) I think this is unlikely.

The last is wear of the mechanical components. I looked at (but did not really inspect) the ramp and although there was some wear apparent there was no scoring or real unevenness except a dimple on the up side of the ramp. However, you could see it had been used. Likewise the nibs on both the switches looked pretty much as you would expect (not that I'm sure that any wear here would be immediately detectable. It occurs to me that if the ramp is more worn than it appeared it would wear the nib prematurely.

With this in mind I have been on to SVC and ordered a brush plate, a new wheel and (yet another) park switch.

It strikes me these are all wearing parts and so I am unlikely to be wasting my money. I will then give it all a good clean out and replace the grease (any recomendations? It looks like ordinary yellow grease in there) and see how we get on.


Chris


1979 SE6A

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Re: Wiper Motor Repair Guide

Post by tony.idle » Mon Jan 09, 2012 12:51 pm

Chris

IIRC you did the correct test by removing the parking switch & operating it by hand. If by emulating the ramp on the wheel you can make everything work correctly then the park switch plunger or ramp are at fault. By "make everything work correctly" I mean everything except parking in the correct position. I bought the correct grease years ago - I'll try to remember to check when I'm next in the workshop. It definitely isn't general purpose stuff.

One fault that can cause the wheel to shift with respect to the switch plunger is a missing circlip on the end of the wheel shaft (opposite side of the motor to the mechanism cover plate). With this missing everything will work correctly apart from the parking switch.


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Tony

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Re: Wiper Motor Repair Guide

Post by Taggers » Mon Jan 09, 2012 1:21 pm

Thanks Tony. The circlip is still there, I've failed three times to lose it.

Thanks for your help.

Chris


1979 SE6A

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Re: Wiper Motor Repair Guide

Post by Taggers » Tue Jan 10, 2012 10:14 am

Ok, the bits arrive today, so the wipers have behaved perfectly! Slow, fast, park.

Whatever's changed the slow speed is much slower than the previous fast (slow) speed. The fast speed is slower than the previous slow (fast) speed. I'm thinking now, that with the wipers going so fast maybe the linkage has been acting like a flywheel and carrying the ramp past the switch before it has a chance to work!

Anyway I'm hoping it is some sort of a short (ideally at the brush plate and flyleads, thanks) which will be rectified with the new bits. Of course if it's on the other side of the loom it will just come back.

Meanwhile the heater fan, main beams and half the dashboard lights have given up. So business as usual.


Chris


1979 SE6A

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Re: Wiper Motor Repair Guide

Post by Taggers » Sat Jan 14, 2012 9:28 pm

Ok. Wiper motor rebuilt, nothing much to add to Joey's excellent write up, the brush plate is a matter of three screws. The biggest challenge is not destroying your new brushes with the armature, and not transferring grease out of the gearbox into the motor.

I found the insulation at all three wires where they go into the casing was holed, so that, combined with the flywheel effect and fusebox damage was what it was all about.

The new gear and park switch are probably completely unnecessary, but at least now I can have confidence in them.

Chris


1979 SE6A

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Re: Wiper Motor Repair Guide

Post by Gemini Bob » Sat Jan 14, 2012 9:29 pm

Sorted :D


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Re: Wiper Motor Repair Guide

Post by tony.idle » Sun Jan 15, 2012 12:27 am

Chris

I'm glad you got it sorted :). You may already know this (now!) but the best method of fitting the armature without risking the brushes is to pull them back by the pigtails which can then be trapped behind the brush holders to hold the brushes back. Then fit the armature on its own. Release the brushes. Trap the worm with a screwdriver then fit the cover & magnets.


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Re: Wiper Motor Repair Guide

Post by gordonmc » Mon Aug 01, 2016 11:27 am

This thread was invaluable as I refurbed both the rear and front wiper motors on my SE6a.
The main problem on the front was intermittent failure to park. I replaced the brush plate as a matter of course and the park switch. Still no park, so a new wheel went in.
Talk about red herrings. My multi-meter told me there was a live feed to the parking switch in addition to the (green/yellow) permanent live.
The culprit was at the column switch.
One of the uninsulated femail terminals had come off its pin and was making contact with the always-on.
All the femail terminals now have heat-shrink insulation and I have a functional wiper motor.



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