Articulating windshield wipers - PeachParts Mercedes-Benz Forum

JimFreeh · #1 10-19-2007, 06:22 PM

For those of you with later model Mercedes with the articulating arm, I've
been seeing a number of failures recently.

The grease in the head of the wiper gets hard, and the plastic teeth that
move the arm in and out get chewed up.

Result is the wiper jamming, or jumping time so the arm does not extend at
the 45 degree point.

What is happening is that the teeth that are fixed to the head get sheared,
which allow for the jumping or jamming.

Mercedes does not service just the plastic teeth, preferring to have the
owner buy a new assembly. Priced one lately? Would probably total an early
W124 or W201!

Subject car is a 1992 500SL, but it is typical for the W124, W201, W140, and
probably others....

Upon disassembly, maybe 40% of the teeth had been sheared off. Wiper was
jamming when turned on, would work for a swipe or two, then jam.

We removed the plastic teeth (2 sets) from the head, and cut off the
remaining teeth. Need to keep the top portion, since that is a labyrinth
seal for the head. Explaining further, the the system works like a rack and
pinion. The rack is attached to the wiper head and the pinion is attached
to the wiper arm. The rack is what is removed...

The arm is set to the retracted position, which appears to be a null
postion. Pulling on the arm does not extend it.

Reassembly, without the teeth, and arm in the retracted position resulted in
a wiper that worked fine without the articulation.

So far, we have not had any problems with it, and if the arm eventually
starts to extend, there are ways to lock the arm in the min position.....

Not my first choice of repair, but for a seldom used roadster that need to
pass state inspection, this fix did the job!

TheEngineer · #2 10-20-2007, 12:16 PM

How about obtaining an assembly from a junk yard?

amgraves · #3 10-21-2007, 12:26 PM

How about obtaining a new gear from www.odometergears.com and fix the problem correctly! Only $125 for the gear.

Aaron

JimFreeh · #4 10-22-2007, 10:03 AM

Quote:

Originally Posted by TheEngineer

How about obtaining an assembly from a junk yard?

Sure, got a spare $350?

Jim

JimFreeh · #5 10-22-2007, 10:06 AM

Quote:

Originally Posted by amgraves

How about obtaining a new gear from www.odometergears.com and fix the problem correctly! Only $125 for the gear.

Aaron

Thanks Aaron!

That's a great solution.

Jim

amgraves · #6 10-22-2007, 04:30 PM

No problem. My 1991 300E decided to strip its gear last Friday and thanks to a BMW mechanic friend of mine, I learned about the new gears being made by the owner of odometergears.com. I hope that this will help many of us that seem to be having problems with our wipers and have settled for lesser alternatives. This is a great site that I enjoy very much!

Aaron

oestek · #7 10-23-2008, 06:17 PM

Did you have to remove the whole wiper transmission system from the car to replace the gears? This just happened to my '95....

Thanks!

amgraves · #8 10-23-2008, 10:08 PM

Yes. You will have to remove the complete wiper assembly to replace the worn plastic gear. It is not a hard job but everything should be marked for proper function after reassembly. The wiper MUST park in a particular position or you WILL exhibit problems of the blade hitting the hood.

Aaron

ds190 · #9 10-24-2008, 12:02 PM

FYI, that plastic gear is also available from ************************. About $100.

oestek · #10 10-24-2008, 03:36 PM

Do you need to buy 2 replacement plastic gears or one?

Thanks!

Bob Weir · #11 10-24-2008, 06:37 PM

Only one plastic ring gear about 3" diameter. The other is a metal worm gear.

However, I'd take it apart first. Sometimes it's the motor. I bought motor [with integral transmission] assembly for $75 from junk yard through "car-part.com" and saved on shipping by not getting the entire arm assembly. A failing motor will swing the arm, but not as fast as it should.

I'll assume a 190 is similar to my 124 in that:
1] it takes more time to remove all the plastic surrounding the cowl, than to pull and dissemble the wiper motor trans assembly,
2] the heater motor is under the wiper assembly and its the ideal time to pull the heater motor and lubricate the squirrel cage,
3] change cabin air filter.

Pooka · #12 10-25-2008, 09:25 PM

This sounds like a great solution, but here is another one...

On my 1992 300D I could not find the plastic teeth for sale (this was several years ago) but I did open up the wiper gear assembly from a 1985 190E and found the same teeth with one difference: the 190 gear teeth were bronze!.

I removed them from the 190, installed them in the 300, and greased it all up. It worked great.

Mercedes wanted $990 for the assembly.

Pooka

oestek · #13 10-19-2009, 11:41 AM

I replaced the gear in my W140's wiper system over the weekend... not a terrible job. Here's a pic of the broken original gear...

(Raisinettes not needed for repair, but helpful.. )

alsevi · #14 09-21-2019, 10:53 PM

Just did this, 96 S500 W140. Plastic pinion gear failed, arced rack gear was ok. Great write-ups, thank you. I add that the timing is critical and tedious Specifically, when the gear fails the orientation of the transmission housing to the wiper frame remains intact, as stated, and clearly mark it with the motor in the rest position. This will ensure correct phase (arc) on reassembly. and readily achieved. The problem is that when the gear breaks, the position of the wiper extension is lost (articulation). The correct position is articulating arm fully retracted with the motor at rest, marks lined up position. Unfortunately, you can not readily set this on reassembly because there is a permissive assembly notch on the rack that only allows gear to rack placement in the wiper (transmission) vertical position. So you have to engage the gear in the rack vertical and rotate the transmission to the motor rest timing marks position and look to see if the wiper arm is retracted. Has to be or it won't work (wiper blade hits wind shield side molding). If unsuccessful, rotate transmission back vertical so you can pull it apart, reset a new wiper arm extended assembly position, set the transmission back in, rotate transmission back to rest marks lined up an see how you did. Repeat..... It has to be perfect - marks lined up, wiper arm fully retracted. Lastly, when you connect the linkage to the transmission shaft, go steady as to not pull the transmission off the timing marks. Test run it with the driver side blade installed prior to putting all the plastic back on.