Fintail Wiper Motor - PeachParts Mercedes-Benz Forum

CTD · #1 09-08-2017, 10:37 PM

The windshield wipers quit on my Fintail recently. When I turn on the ignition, they budge a slight bit from their parked position. When I turn off the ignition, they move back down (this motion and position change is very subtle). I opened up the hood, and the wiper motor felt quite hot to the touch, so I unplugged it and applied Rain-X to the glass.

Do you think the motor could be dead? Or could it be a problem with the linkage? I would prefer it to be the motor as the wiper linkage is buried quite deep under the dash while the motor is easily accessible.

meltedpanda · #2 09-10-2017, 10:06 AM

disconnect the linkage at the motor and then run, if the motor turns and sounds good it would be the linkage

CTD · #3 09-19-2017, 10:12 AM

I removed the wiper motor from the linkage this morning, and ran it in the engine bay. The motor's shaft turns good at both speeds. So I crawled under the dashboard to have a look at the wiper linkage.

The linkage has a long connecting rod between the two wipers, but it refuses to budge (even though it should move from side to side as the motor turns a crank). I looked at both ends and all the linkage appears to be intact. Could it be that it got shoved beyond its normal range at some point?

All the pivot points appear to be in good condition, although two of them on the passenger side appear loose. Are there any loose-looking pivot points on 'good' wiper linkage (they are visible under the dash from the passenger footwell)?

meltedpanda · #4 09-19-2017, 08:35 PM

IIRC , the linkage is a loose fit on all pivot points , perhaps yours have locked up for some reason. If I get a chance in the next day or so , I will get under the dash and look at mine

CTD · #5 09-19-2017, 09:05 PM

That would be very kind of you! The visual inspection of my wiper linkage didn't really reveal to me anything that was particularly out of line, except for the fact that the linkage refuses to budge. I wonder if something caused the linkage to extend beyond the range of its normal travel and bind up.

It would be nice to get a look at the wiper linkage in another fintail, but they are virtually extinct where I reside. I think there are only twelve or so remaining on the road in my state.

Access to the wiper linkage from under the dash isn't as bad as I thought it may be, but that could perhaps be due to my vehicle's lack of the Kuhlmeister A/C unit. The A/C would cover the long connecting rod, though, rather than the rotating assemblies on the ends.

meltedpanda · #6 09-19-2017, 09:40 PM

OK will do in the next day or so

meltedpanda · #7 09-19-2017, 10:02 PM

OK , I figured if you are like me you don't like to wait. I went out to the shop to look . On the passengers side the arms connect to the motor of course and ALL the joints are loose. I would equate it to a ball and socket type attachment . I suspect one of those is frozen either there or on the drivers side . It is possible the drivers side has become partially dislocated or frozen. Can you move the wipers at all with the motor disconnected , could they have tightened down somehow ?

dobrodan · #8 09-20-2017, 09:24 AM

Pull the wiper blades off and the chrome covers. Sometimes one or both of the posts will seize up and you can usually free them up with a good penetrant. The best available is a product that you can get at a Dodge or Chrysler dealer parts department. It is amazing stuff. Let them soak for a while. You should be able to move the wipers by hand when they are free.

CTD · #9 09-21-2017, 07:47 AM

Meltedpanda - Thanks a lot for taking the time to crawl around and look at your wiper linkage. What you describe is quite similar to mine. The pivot points on the passenger side of my linkage are a ball-and-socket type, and appear to be in reasonably good condition.

Nothing in the linkage under the dash looks to be overtly damaged, so I am suspecting that something along the lines of what Dobrodan describes in post #8 has happened: a wiper spindle siezed.

I am wondering if it could be the spindle on the driver's side. This spindle was originally broken off at the top, so I drilled it out and tapped it, and inserted a piece of threaded rod to replace the threaded end that broke off. It worked fine for a while until one morning when the wipers quit. I wonder if there are any bearings in the wiper spindles, and if one of them could have seized.

I shot both wiper spindles with some penetrating oil, but I don't have the right spanner wrench to remove the chrome-plated circular covers around them that keep the cowl on.

Now a question for me to ponder is: is it possible to replace and/or service the spindles without removing the dash pad?

meltedpanda · #10 09-21-2017, 10:39 AM

yes sounds like its topside in the spindles , once you uncover them you will be able to lubricate and take a look, but removal may be a pain with dashpad removal.
Actually have removed and replaced my dash pad, not really too daunting, lots of connectors and such and you have to be a contortionist but pretty straight forward. That said, not for the faint of heart, and suggest you remove front seats

CTD · #11 10-07-2017, 09:11 PM

Well, I've given the wiper spindles some time to free up with penetrating oil, but they do not wish to budge. With the existing linkage having that broken spindle that I rigged up before, I think I am going to start looking for a 'new' good set of wiper linkage. Until I find one, though, some Rain-X on the glass will have to do.

Looking in the car, I suspect that the wiper linkage will come out from under the dash, which means the heater and radio will have to come out. The car has no A/C, which I think will make things a little easier. Has anybody on here ever done this job? Since the linkage appears to be installed/removed from under the dash, I think it may be possible to do it without taking the pad off.

meltedpanda · #12 10-07-2017, 09:52 PM

Without the AC you will be able to reach everything without taking the pad off. It will be a bit tight. I’d move both seats all the way back or better yet take them out. Have fun!