W124 Mono-wiper motor brushes - PeachParts Mercedes-Benz Forum

indybenz · #1 03-01-2016, 06:32 AM

It's been a loooong time since I've been here on the forum, but good to be back.

I now have an RHD W124 300TD Estate (non-burbo ;-/). Why they wanted to put a 109 horsepower engine in such a heavy car will never make sense to me.

Anyways, my front wiper is sluggish and does not work on the highest setting. After some testing and some research, I decided to disassemble it, clean/regrease it, and perhaps replace the motor brushes.

Here are some pics of the brushes. Do they look like they need replacing? I'm not an expert. But if I replace them and it goes well, I'm happy to receive shipments of your wiper motors that need brushes and fix them for a small fee to save you the cost of a new motor!!! ;-)

Stretch · #2 03-01-2016, 07:15 AM

They still have some life in them - but be careful now they are out they are at their most vulnerable.

If you look at the ends you can see that there are some small ridges forming where they touch the commutator. You could dismantle further and clean up the commutator on a lathe (if you have one). Alternatively - with extreme care - you can do this with sand paper too. See for example here =>

Achtung - Das schweinhund baby benz thread

This is a not so an ideal fix but can make a scored commutator a bit happier for a while.

Leave the brushes alone - they will wear quickly to the correct place.

##########

To find the brushes you need you need to identify the electric motor part number. If it is a Bosch unit (not SWF) then you stand a good chance of finding the correct parts.

Stretch · #3 03-01-2016, 07:17 AM

A sluggish wiper is more likely due to the grease on the inside of the mono wiper assembly.

See here for some mono wiper fun.

(Same thread different post)

Achtung - Das schweinhund baby benz thread

indybenz · #4 03-01-2016, 07:50 AM

Cheers mate! I wondered if I'd see you again on here. Perhaps I need a road trip to Holland to meet up ;-) LMK if you're ever in the UK, particularly Scotland.

I've seen that thread and will revisit thanks. Also, found a thread on oldmerc site that said any brushes that were the correct size would do.

TTFN

babymog · #5 03-01-2016, 08:03 AM

You could go either way, looks like your brushes are ~50%.

Once the system has been cleaned and re-lubed, it will work fast as original, and this will draw less current, which will help your brushes and commutator wear longer. As Stretch says, clean it all up, and be sure to clean up any copper/brass shavings which will also cause arcing and higher current draw.

Once you're in this far, brushes are so inexpensive, might as well replace them IMO, but that is the only reason.

jbach36 · #6 03-02-2016, 12:45 AM

I have a 2 year old rebuilt mono wiper motor for sale for $30 plus $10 shipping. Email me if interested.

Stretch · #7 03-02-2016, 09:25 PM

Quote:

Originally Posted by indybenz

Cheers mate! I wondered if I'd see you again on here. Perhaps I need a road trip to Holland to meet up ;-) LMK if you're ever in the UK, particularly Scotland.

I've seen that thread and will revisit thanks. Also, found a thread on oldmerc site that said any brushes that were the correct size would do.

TTFN

Once in a while I visit South East England. I rarely go to Scotland but have some friends up North I should really go and see again.

If you get to Holland give me a shout.

optimusprime · #8 03-03-2016, 04:55 AM

True as said , that any brush the same size will work fine. Just rebrushed the alternator regulator same way.

Chris W. · #9 03-05-2016, 08:33 AM

In my experience new brushes will not improve the wiper sluggishness much, if at all. The old ones are worn, but not grossly so. I'd focus on the mechanism, as others have said.

Rgds,
Chris W.
'95 E300D, 460K

indybenz · #10 03-09-2016, 11:36 AM

Thanks everybody. I was putting the motor back together and broke the wafer the brushes are attached to. Doh! So I got a used motor off ebay. Cleaned out the old grease and installed in the car.

Now, here's where it gets interesting. Ok, not really. Lots of cursing and starting over. I thought I followed the directions to install it so it would know when it was 'parked', and therefore be in the right position.

I was wrong!

When I finally put everything back together, THEN put the wiper blade on, it extended off the windscreen at the bottom (at the wrong point). I marked the motor and the 'arm' where it attaches, but that didn't seem to be the proper place to mark the parts.

Hours later and totally dejected, I've given up for today.

Any suggestions on how to make sure the motor and the mechanism are lined up properly so I can get back on the road?

Thanks.

EDIT: now that I've written this, I think I know what the problem is. Off to check it out...

CarpeDiem51392 · #11 03-10-2016, 11:25 AM

Figure it out?

I had a similar experience with the "transmission" linkage. I did not disconnect the connection at the motor but instead disconnected the other side so to speak to grease the assembly. I also scribed a mark but after re-assembly the wiper traveled too far on one side and not far enough on the other. The solution was to scratch my head for a bit to figure out which way to tweek the assembly and retighten. That fixed it, don't think it's the exact sweep pattern as stock but there is some room for error. Hope this helps, I'm not sure how applicable this is to your situation.

indybenz · #12 03-10-2016, 03:23 PM

I did figure it out! It was as I suspected. I took everything apart again and made sure that everything was in the right place first, then put it all back together. Turns out, everything was *mostly* in the right place as it now 'parks' too far up the driver's side. I can fix it later but the great news is now I have THREE speeds for the wiper! Living in Scotland where it rains much of the year almost necessitates having the wiper system working properly. Up until now, I only had intermittent and 'low' with no highest setting (it would bog down and stop working). Along with the recently fixed rear wiper/washer/defrost, it has made for much more pleasant/safe driving.