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Ronza85
08-20-2014, 05:19 PM
Hello-

I'm trying to help a friend out who owns a '93 500e. His wiper has been going very slow and groaning quite a bit for sometime now, it would only function at the lowest speed. Now it stopped working completely. Where should one start to diagnose this problem? Any diy instructions available? Thank you.

gsxr
08-20-2014, 05:43 PM
If it's been slowing and finally died, most likely the complete wiper assembly (motor+transmission) requires replacement. You could attempt to take it apart and lubricate, but it is easier and cheaper to replace them. The design changed in late 1993 model year, be very careful to buy a replacement that is the same style, and only from a sedan or wagon.

:banana1:

Ronza85
08-20-2014, 06:48 PM
If it's been slowing and finally died, most likely the complete wiper assembly (motor+transmission) requires replacement. You could attempt to take it apart and lubricate, but it is easier and cheaper to replace them. The design changed in late 1993 model year, be very careful to buy a replacement that is the same style, and only from a sedan or wagon.

:banana1:

Thanks GSXR, can you please confirm part # 0390241425 is what you are referring to for an early '93 build date? This part # looks to be the motor. Do you happen to have the transmission part #? I was under the assumption he would just need the motor. Your help is appreciated.

gerryvz
08-20-2014, 06:55 PM
It's often the gear wheel in the assembly that disintegrates. The motors don't wear out as often.

I agree with Dave that it's much easier just to replace the whole assembly with a used one, rather than disassemble it, try to figure out what's up, and replace the gear if necessary (it's available aftermarket as an inexpensive replacement). You can usually get a used assembly for $50 or less at the wrecking yard.

Also, when you do install the new unit, be sure to take the opportunity to properly lubricate everything. This should keep it going for at least the next 10 years.

Cheers,
Gerry

gsxr
08-20-2014, 06:59 PM
EPC calls it "Gearing" and through 1993 is p/n 124-820-23-07, with a scary footnote "To be adapted during assembly". Almost $1000 list price. The motor is sold separately.

0390241425 is the Bosch part number (not MB part number) for the motor only, and it is not likely the problem is the motor... maybe Jono, Clark, or Klink can chime in, I'm sure they've dealt with many of these in the past.

:scratchchin:

maw1124
08-20-2014, 07:33 PM
When mine went bad, it was the gear assembly, as Gerry indicated. My guys have a source for a gear replacement (around $200 -- since in SoFL there are tons of old one-arm Mercs roaming the countryside). So they disassembled, installed the replacement gearing, lubed it all up and reinstalled it. Maybe it was 3 or 4 hours labor.

They advised against a used part because in their view, they all go eventually, so you could be installing multiple used parts. But if it's a DYI thing for you (as I suspect it is for Gerry), then it may be worthwhile to throw used parts at it.

Good luck,

maw

Ronza85
08-20-2014, 07:47 PM
Thank you. What I find interesting is the washer fluid is not spraying on it either now, it's almost like the fuse went on it too if it controls both the wiper and spray.. The fuse guide is missing so I am having trouble confirming this and which fuse needs to be checked. Can someone please confirm?

I was in my friends car when the wiper stopped, I am now a true believer in Rain-X because the water just beaded off his windshield or we could have been sitting under a bridge until things cooled off. Love these type of products that actually work!

Trae
08-20-2014, 07:59 PM
Found this from Kent.

Have not attempted it yet, because I hope someone else will do it and give us more tips!

https://www.youtube.com/watch?v=W3IPjKgC5AQ

gerryvz
08-20-2014, 10:40 PM
This seems to be a very common problem these days with Mono-Wipers. The symptoms typically include a very slow wiper movement along with hesitation as it reaches certain points on the wiper cycle. This fix essentially lubes the wiper mechanism. It is probably a good idea to do it yearly to keep the wiper moving well all year.




Step 1: Set the wiper system to approximately straight up and down on the windshield. This can be achieved by setting the wipers on and turning the ignition key to OFF at the appropriate time. It may take a few tries to get it right.




Step 2: Pull off the middle plastic cover by pulling down and out on it (See picture). This reveals a hex screw. If you wish to remove the entire wiper arm, this can be done by removing the hex bolt. This procedure is not necessary to lube the wiper mechanism.

https://www.500eboard.com/forums/images/imported/2014/08/223.jpg




Step 3: Remove the main cover piece by pulling out and up on the two release tabs (circled in the picture) . I used my fingers, but you might need to use something pull the tabs outward and up.

https://www.500eboard.com/forums/images/imported/2014/08/224.jpg




Step 4: Before you pull the cover all the way off, set the wiper to approximately 45 degrees so the wiper is at full extension. Make sure everything is clear of the wiper mechanism as it is very powerful!



Step 5: Now remove the cover completely and expose the wiper mechanism. I used White Lithium Grease because it is water-proof and it is a spray-on sticky grease. I have had good luck with the grease lasting all year. Make sure when greasing to particularly spray the vertical sliders that keep the wiper linear.

https://www.500eboard.com/forums/images/imported/2014/08/225.jpg


Finally, Put everything back together in the order it was removed. Once back together, run the wiper cycle several times to work the grease in.

Trae
08-21-2014, 06:02 AM
Fantastic write up again Gerry.

Thanks!

Ronza85
08-21-2014, 07:08 AM
Thanks Gerry, I looked over a few things yesterday after the wiper was inoperable. I noticed the washer fluid stopped spraying too. Do you think a fuse might have blown? The fuse guide is missing on his car so I am not sure which fuse controls these components. I'm thinking the wiper and washer system might operate on the same fuse like one of my older MBs. Just not sure which fuse it is on these cars??

Does the procedure you have listed above work on the 500e? He told me that the base part of the wiper does not have the two tabs to remove and expose the vertical risers. I think this might just be on the 202s and a few other models after '94. I was under the assumption this the procedure required a little more work on these cars. I will be going over to his place after work today, so any further advise would be appreciated!!

mistermiata
08-21-2014, 08:05 AM
Pretty sure Kent has you on this one Gerry :omg:...according to the video Trae posted, the whole wiper mechanism needs to be removed to get to the hidden screws underneath that allow the cover to be removed. Doesn't look like it can be done on the car

gerryvz
08-21-2014, 08:43 AM
That's not my write-up - I cut and pasted it from a W202 site (my HOW-TO articles IMHO are better quality) but it should help with disassembly and lubrication on the mono-wiper setup.

gsxr
08-21-2014, 04:17 PM
WARNING!

The writeup above only applies to 1994-up wipers. The 1993 and older version CAN NOT be easily taken apart for cleaning / repair.

:mushroom:

Ronza85
08-21-2014, 07:20 PM
I wanted to post an update on this problem and ask for some feedback please. After work I went to my colleagues house to further investigate his inoperable wiper problem, I personally own a W202 but am not well versed on the W124s like you guys. This is what I know so far, the wiper, washer spray and high beam when pulled inward on the stalk is not working. The high beam does work when the stalk is pushed outward to stay on constantly. I am starting to think a fuse might have blown to save the motor on this wiper due to it running so slow yesterday. Unfortunately the fuse schematic is not in his fuse box, but I believe its fuse#2 after returning to my house and doing some research. I was also not aware these cars use a different fuse than mine.

Can someone please confirm that I am on the right track here with regard to diagnosing? I will be helping out this weekend and would really like some input. I looked on my W202 fuse chart and my wiper fuse operates these same components that are not working on his car. He loves this car as one should, the last thing I want to do is muck anything up on his 500e, please let me know your thoughts. Thanks again!!

Cheers,

Klink
08-21-2014, 07:56 PM
WARNING!

The writeup above only applies to 1994-up wipers. The 1993 and older version CAN NOT be easily taken apart for cleaning / repair.

:mushroom:

Actually, Kent's video that Trae posted above does show the early version with some good info on getting it apart. A friend of mine recently had success with Kent's video. His plastic ring gear was broken and he sourced a new one from I believe Eckler's for a not inconsiderable sum. But it all did work, and there he was with a perfect wiper transmission again for 100 bucks.

Klink
08-21-2014, 08:02 PM
I wanted to post an update on this problem and ask for some feedback please. After work I went to my colleagues house to further investigate his inoperable wiper problem, I personally own a W202 but am not well versed on the W124s like you guys. This is what I know so far, the wiper, washer spray and high beam when pulled inward on the stalk is not working. The high beam does work when the stalk is pushed outward to stay on constantly. I am starting to think a fuse might have blown to save the motor on this wiper due to it running so slow yesterday. Unfortunately the fuse schematic is not in his fuse box, but I believe its fuse#2 after returning to my house and doing some research. I was also not aware these cars use a different fuse than mine.

Can someone please confirm that I am on the right track here with regard to diagnosing? I will be helping out this weekend and would really like some input. I looked on my W202 fuse chart and my wiper fuse operates these same components that are not working on his car. He loves this car as one should, the last thing I want to do is muck anything up on his 500e, please let me know your thoughts. Thanks again!!

Cheers.

The fuse card is usually inside the fuse box, are you sure his is missing? You would be well served to remove and check all the fuses pretty much regardless. Only remove them one at a time, keeping track of where you removed it from. That process will only take a few minutes and could save you no end of wasted time. Those turn signal stalk / combination switches do occasionally fail in strange ways producing behaviors like this one. Had one behaving similarly (but not exactly, mind you) on a 124 Cabriolet just recently.

Allgonquin
08-22-2014, 07:32 AM
On my diesel 124, which I am not cosmetically concerned about (shall we say) I replaced the entire wiper ass'y with a boneyard unit. When that one slowed down, I knew I could not easily disassemble, so I drilled a hole in the cover (which is aluminum) just larger than the ubiquitous red spray tube diameter and "injected" a good blast of spray grease. I cycled the wiper and did it again. Yes, a few metal chips undoubtedly dropped into the casing, but no big deal. I plugged the hole with a tiny dab of silicone. Been good for several years now. If it slows again I'll redo it. Would I do it on my 500 if it ever needs it? Dunno. But $1K for a new one is tough to swallow. Can someone get the actual contact info for a rebuilder?

Ronza85
08-22-2014, 11:33 AM
On my diesel 124, which I am not cosmetically concerned about (shall we say) I replaced the entire wiper ass'y with a boneyard unit. When that one slowed down, I knew I could not easily disassemble, so I drilled a hole in the cover (which is aluminum) just larger than the ubiquitous red spray tube diameter and "injected" a good blast of spray grease. I cycled the wiper and did it again. Yes, a few metal chips undoubtedly dropped into the casing, but no big deal. I plugged the hole with a tiny dab of silicone. Been good for several years now. If it slows again I'll redo it. Would I do it on my 500 if it ever needs it? Dunno. But $1K for a new one is tough to swallow. Can someone get the actual contact info for a rebuilder?

Wow our minds think alike! I thought the same thing too last night after seeing the extensive procedure, if he was going to have to replace the internals and body anyway that it might be worth the shot. Small little hole then some cover up.

We just replaced the fuse and all is working, still very slow. I removed the middle plastic piece which is very simple to get off and hit that with a good amount of white lithium. It needs a little run in the rain now to see if that helps and do not want to try it on the dry windshield.

Thanks,