Any [2 speed] wiper motor experts here?

[Randy Forbes]

As a result of the rollcage being in the space of the original motor, an MGB 2-speed wiper motor (mounted under the cowl on rh side) has been fitted. In an effort to get the car licensed in Ohio, I'm trying to make everything work...

The problem I'm having is getting the motor/wipers to STOP; both speeds work okay, but it seems to coast past the deadband of the neutral switch and then starts another cycle.

If I snug up the armature endfloat adjustment, I can provide enough of a braking action so the motor stops within the deadband, but that can't be too good for the bushes, as there's supposed to be .004" endfloat.

Any suggestions, as I'm stumped?!

 

[BlueRidge2]

[quote

The problem I'm having is getting the motor/wipers to STOP; both speeds work okay, but it seems to coast past the deadband of the neutral switch and then starts another cycle.

Randy, Is this ocurring with the motor in place with the wipers contacting the windshield or bench testing with out any resistance from the wiper to windshield contact?
If it is with the wipers in place maybe you could increase the deadband area slightly. Just a guess. Bob

 

[Dave Russell]

I "think" the wiper motors have a "park" function. When the switch is turned off, the wipers should return to the parked position. This position is adjusted by rotating the top cap on the wiper motor (the contact under it - neutral switch) until power is shut off at the correct position, allowing for any coast. Loosen the cap hold downs slightly. Note that the wiper on/off switch actually feeds through this park contact while hot & ground are not switched.

Fine adjustment can be made by shifting the wiper arm on it's serrated shaft.

This is why even single speed wipers have three wires. If you just shut the power off, the wipers will end up at random locations. With the park switch correctly adjusted, they will always return to proper parked position. All Healeys had this feature except the earlier BN1's.
D

 

[Randy Forbes]

Thanks guys.

I have tried the motor on the bench as well as in the car with the linkage and wipers fitted(dry screen too). Still coasts past the limit switch stop. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

The MGB motor is similar to the original Healey unit, just offers another speed (though the park switch is less user friendly).

Unfortunately, my original (plus spare) wiper motor(s) are in Florida, or I'd just abandon the two speed MGB thing and fabricate a suitable mount for the Healey motor on the right side.

I'm not beaten yet, but I'm wearing down...

 

[Dave Russell]

Still coasts past the limit switch stop. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

Hi Randy,
Can you set the wiper arm base serrations around a couple of notches on their bases so that they coast to the desired parked position. You should be able to make the final at rest position come out anywhere you want. It worked for me with the original parts. Or, set the limit switch to shut off sooner so that they over travel to the correct position. Maybe I just don't understand?
D

 

[GregW]

This probably falls into “do or die surgery”, but I’ll throw it out there anyway. If the motor spins past the park zone, maybe cutting some of the copper contact off to widen the park area would do the trick.

 

[piman]

Hello greg,

I don't believe there is enough inertia, even with the wiper motor on the bench for it to coast beyond the dead stop.
Unfortunately, I don't have a diagram for your wiper. But if there is a green wire to the motor and a green wire to the control switch, disconnect the green wire on the motor and it should then stop whenever you switch off the control switch. If it does not then you have some crossed wires at the motor.

Alec

 

[john_j]

This probably falls into “do or die surgery”, but I’ll throw it out there anyway. If the motor spins past the park zone, maybe cutting some of the copper contact off to widen the park area would do the trick.

I suspect this photo is of the earlier motor - can the OP confirm this?

I've just fitted an MG 2 speed motor, and so far haven't worked out how to make it park.

The park switch is in the bottom of the body, and won't be as easy to adjust as the old type.

There are 5 terminals on the later motor set out like this - 1
2 3
4 5
(or maybe 3 and 4 are swopped over, can't remember for certain.)


1 is Earth
2 - Slow speed
4 - Fast Speed
3 - Something to do with parking
5 - something more to do with Parking

I think 5 is power, always on and 2 and 4 are earthed via the switch.

3, I'm not sure. On a B it apparently goes to the switch.

I've got mine to work on slow speed but putting 1 to earth (-ve) and 2 to power (+ve) via the switch, so far the only poark is make sure you turn it off at the right time.
I'll work out the refinements when I have some more time!