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Mark Desimone wrote:Of course the next time it rained, I got in my car, turned my wipers, and nothing happened. I replaced the fuses just in case and no change. I got out my circuit tester and tested the connector to the motor and it lit up, so I know it is getting juice to the motor.
Not sure if there is anything more to test... any ideas? If not, I would like to know what my options are to replace it. Do I need to go OEM or are there cheaper alternatives or can I grab one off another BMW model? Help...
I'd suggest trying to fix yours before you do anything else. You'll have to take it out to replace it, and it's a pretty simple job. Supplies:
Medium grit sandpaper (180 or so)
Fine sandpaper (at least 600) or emery cloth
Electric parts cleaner spray (like Electromotive)
WD40, Kroil, PB Blaster, etc.The easiest way I've found to get at the motor is to pull the entire wiper assembly, and this way you can lube all the rotating points so you get maximum wiper speed (such as it is). First remove the 5 or 6 screws holding the heater fan cover and remove the cover (some are hidden under the hood seal). Then remove the wiper arms, and remove the large nuts that hold the wiper arm pivots to the cowl. Take the bolts out of the driver's side hood catch, loosen the little bolt that grips the cable and rotate the catch out of the way. Unbolt the driver's side window squirter and move it aside.
Spin the rubber wiper motor mount up as far as possible without taking it completely out. Unplug the 3-wire connector and the separate ground wire.
Now carefully press the wiper pivots down through the cowl, and work the assembly out from under the cowl. It takes a little maneuvering, but it does come out without the use of a pry bar or any cutting tools.
On the bench, remove the 2 screws from the end of the motor that hold the cover on. Carefully pull the motor apart -- it will probably pull the drive end out of the gear housing first, then you'll be able to pull the armature from the case. Be gentle, as the brushes are mounted on the gear housing.
There are a couple of nuts in the motor case that those screws thread into,don't lose them. They're held in place by what is now some very dry and brittle old electrical tape.
Check out the brushes and see if they are in OK shape or need to be replaced. They'll probably be OK, they last a long time. As long as they are about 1/4 inch long or more, they're OK. Make sure the wire is solidly connected to each brush. If they need to be replaced, check your YP for an electric motor repair place, they can sell you brushes or even install them if you don't have a soldering gun.
Now that you're done with the big awkward assembly, set it aside, but first hose down all the rotating points with WD40, Kroil, PB Blaster or whatever your poison is. Let them have a good soak while you work on the motor.
Chances are the armature is rusted to the big field magnets. Hopefully you will be able to pull it out, it may be necessary to knock it loose (gently!) with a plastic mallet or a chunk of 2x4. Just don't bung up the gear end of the shaft. Once it's out, use some medium grit sandpaper and rust off the armature, being careful not to damage the winding. Use some emery cloth or very fine sandpaper (600 or finer) to gently clean the commutator where the brushes ride. Spray the armature clean with electrical parts cleaner to remove any sand grit and rust dust.
Clean the field magnets with fine sandpaper to get all the rust off them, and if the inside of the motor cover is really rusty, use a small wire brush to scrub the scale off, spray the case clean with electric parts cleaner and then just coat it inside with PB or Kroil or WD40, and wipe the excess off the magnets. Alternately, if you have some Rust Mort or naval jelly (you own a coupe, so you should) you can do a number on the inside of the case to convert the rust. Just wipe any slop off the magnets.
If you have some heavy grease like wheel bearing grease handy, put a dab on the end of the armature shaft that rides in the bearing at the end of the motor cover, then slip the armature back into the motor cover and get it seated in the end bearing.
Putting the motor back together is pretty easy, just be patient when working the commutator under the brushes. You can use a toothpick or a dental pick to push the brushes up into their sleeves. Be sure to replace the tape that is holding the nuts in the motor case, I gave it a couple wraps of electrical tape to seal it up nice.
Before you stuff the assembly pack in the car, plug it in and see if it works. If you've not left out any important pieces, it should. In fact, it should be working like new! As they say, assembly is the reverse. Before you install the wiper arms, turn the wiper motor on and off a couple times to assure that it settles in the "park" position. No point in doing all this work just to strip the splines out of the wiper arms as they try to drag across the hood...
E12's have a plastic cover that fits between the gear case and the wiper arm assembly that covers the motor to protect it from water, I think I'm gonna snag one next time I go to the u-pull it. I know my interest in improving wiper motor performance puzzles those of you who never drive in the rain.
All I can say is, it's just a car, and I bought it to drive, not to look at.
When rust finally claims it, y'all can have first go at the parts.