engine and drivetrain Wipers- Venting

[tups]

I need to sit down, have a drink and cool down a bit. It doesn't help that it's about 90°F here, but when driving home today in the '67 1600-2, a problem that has existed for at least 15 years reared its ugly head again. When it's hot outside, and the engine is hot, and you go over a bump, the windshield wipers come on, and there is nothing you can do to switch them back off.

 

So, I thought, it is the old windshield wiper parking problem - lets finally disconnect everything, take out the motor, and have a look at the parking mechanism.

OK, so I did, and everything looks just fine. Cleaned up the motor, new grease on the bearings and the reduction worm gear, I even managed to keep the gasket in one piece, so it should be good for another 40 years. Then all should be good to go.

 

Connect the motor and ground it, and it merrily starts spinning away, while the switch is in the off position.

 

I measure some voltages, and I have 6V to ground on all three connections. Only pulling out the switch to the "fast" position makes the voltage disappear on one connection, and then the motor spins faster.

 

So it has to be the switch, right ? Disassemble the dashboard, fumble with the switch, and presto! Everything works. For good measure I clean up the connections to the switch - everything still works.

 

Then - disaster- I decide to try the windshield spray pump handle, which also switches on the wipers - and then they don't go back off. The windshield spray pump motor gave up the ghost 20 years ago, I've been meaning to buy a replacement ever since, but never did.

 

So then, methinks, it is probably time to get out the wiring schematic, which is printed in very thin black-and-white lines in the back of the owner's manual. There also appears to be a separate "delay relais" which could also be the problem. In addition, similarly coloured wires which I thought to be obviously two ends to the same wire, turn out not to be.

 

Now I am very hot, very confused, and in need of a drink. The I'll draw out the wiring schematic and see if I can make any sense of it at all.

 

Pff...

 

 

 

 

 

 

 

 

[tups]

Right - the electrics operating the wipers on the early 6V 1600-2 were designed by the German equivalent of Marquis de Sade.

I figured out what was wrong. It was the parking mechanism anyway. The tab connected to the green-blue wire that connects to the black wire through the parking mechanism somehow was bent up a little at the connection, and was also making contact there. Judging from the polishing marks, this was also the original problem. Push it back down, and some judicious bending and reassembly later, everything works (except, predictably, the spray pump). 

Somehow during the repair I managed to disassemble my dashboard to have a look at the clock that also hasn't worked for years. Now I'm fabricating extra grounding wires for the dash. Scope creep ...

 

[dbmw2002]

Yes You have discovered the infamous wiper motor meltdown, its sounds like you figured and fixed it pretty qwik. My repair {pre faq} took months to figure out on my own. Luckily it was summer and pulled the fuse, congrats on German thinking

[Mike Self]

If you want to attempt the routine to have your windshield washer pump rejoin the living, drop me an e-mail.  I did a column some years ago on resurrecting stuck/dead washer pump motors.  12v ones are easy to find (used on old VW Rabbits/Audi Foxes) but 6v ones are nearly unobtainable.

 

cheers

mike

[tups]

So, the dash is back together provisionally while I wait for a NOS 6V clock I bought (the old one really was shot on all possible levels - both electric and mechanical). For now, I'm enjoying my rock-steady gauges that don't jump around erratically anymore. Drove the car all day through the heat and the wipers still work fine. The icing on the cake is that with some "judicious" (well, rather "excessive") use of silicone lubricant I managed to free up the motor of the windshield washer pump per mike's column - working windshield washer system for the first time in 20 years, yay!

So what else ... there's a tiny rust patch to repair ...some touch-ups to the paint, perhaps mend the front foglights which also haven't worked for years, I don't even remember which of the two hidden under-dashboard switches they are connected to ... and then install a new windshield rubber which is on order. Then I think it's time for new front strut bearings, and by its 50th birthday we'll have the car better than new!

 

Cris

[tups]

Maybe I should post some pictures of what the inside of the parking mechanism of a wiper motor looks like ....

This is the motor - gearing-cum-parking mechanism lives in the flat can on the bottom left.

 

 

Then we open the can, and this distasteful sight greets us :

 

After a bit of cleaning, you can actually make out how it works - the two contacts are in electrical contact through the metal disc on the gear. Since the green-yellow wire is always hot, it keeps providing electricity to the wiper motor if you turn off the the switch, via the disc and the black wire. As soon as the motor reaches the point in its rotation where the outer contact moves onto the plastic, the contact is broken, and the motor stops.

 

But if the outer contact manages to touch the metal disc with a different part of the spring, and a bit more to the inside, the contact is never broken, and the wiper motor works as long as the ignition is on. You have to shape the spring to make sure that it does not contact the metal disc anywhere else. An ohm-meter on the diode setting really helps. No amount of pushing on or wiggling with the lid may produce a beep out of the meter, otherwise you're guaranteed to get into trouble again.

 

I hope that may be of some help, and an incentive for others to eradicate their wiper gremlins!

 

Cris 

[danco_]

Bump because I am having this issue. Time to take my wiper motor apart. 

 

 

Damn you German Electrical Engineers.