Wiper arm sticks on way and won't move???

[C-Class]

Hi all.

My wiper has been getting a bit "sticky" for quite a few weeks now. I kept thinking it was the screen, or the washer additive I was using.

Anyway, today it finally went accross the screen to the left, but on the way back it locked in the almost vertical position. I have had the covers off and "blathered" it with grease, but it is no better.

The motor is whirring away like a good 'un, but I don't want to keep trying it as I know I am in danger of buggering up the motor.

Does anyone have any ideas as to what I can do next please, as I have a 36 mile commute, and if it rains I am in big trouble.

 

[television]

If the motor is going it should only be the nut loose on top of the motor

 

[C-Class]

Hi Malcolm.

Is the nut for the motor in view once the larger cover is off?

 

[television]

The nut is the one in the center of the motor as in the picture.

That is normally what goes wrong, there is nothing else

http://forums.mercedesclub.org.uk/showthread.php?t=35240&highlight=wiper

 

[C-Class]

Can I get to the nut without taking the whole assy out, as I will have to have a go in the morning before I set off to work.

 

[Blobcat]

Worth having a read or Parrots How to guide in the DIY section.

 

[television]

Worth having a read or Parrots How to guide in the DIY section.

It does not cover this part Blobcat,, I have one computer down to check but I do not think its under the plastic cover

 

[C-Class]

Hi.

I had a look, and it's not visible under the plastic cover. There is a small black plastic cover which has two self tapping screws which is just below the the assembly. Can I get to the nut by removing this cover? I am hoping I can get a spanner in from either this access point, or another to tighten up the central nut.

Are you sure there will be no fibre cog or likewise which might have either sheared it's or teeth, or could be slipping?

It's odd that my wiper goes smoothly from "park" to the passenger side, but stops abrubtly on the way back in the vertical position.

Cheers guys.

 

[Dec]

There are 2 possible causes Nut 1 or 2 in the link below, to access the nut you will have to remove the mechanism, about 2 hours approx.
http://forums.mercedesclub.org.uk/showthread.php?t=35032&page=2
Or
The gears inside motor gearbox have been striped by worm drive or there is damage to the teeth of the worm itself. See post #17… http://forums.mercedesclub.org.uk/showthread.php?t=37082&page=2

This… http://members.lycos.nl/mbenz/windshield_wiper.htm will give you an idea on how to access the wiper mechanism.

Dec

 

[C-Class]

Hi all.

Well, I have had the mechanism apart, and the nylon cog seems in very good condition, as does the metal gearing which it drives.

I have lubricated everything.

I plugged it all back in and tried it, and on the return sweep, it stops at the 11 0'clock position, but I can still hear the motor whirring away. I have to manually pull the arm back to the park position.

Before I spend any money ordering a replacement part, have I exhausted all avenues first?

 

[television]

Sorry that you are not getting anywhere. What has happened is the parking switch is in the wrong place.

If the wiper arm is too stiff, the gears in the box can jump a tooth and get out of line and it stops in the wrong place and cant switch off,, there must be a damaged tooth on the worm or big gear.

I have been trying to get my head around the switch, but I cant see as how it could be this if the motor is still running, it must be a broken stripped tooth where its stopped

 

[C-Class]

Hi Malcolm.

Thanks again for your help. It looks like I will have to shell out for a replacement part.

Cheers.

 

[television]

Hi Malcolm.

Thanks again for your help. It looks like I will have to shell out for a replacement part.

Cheers.

There are lots around being broken

 

[Dec]

Sorry double post
Dec

 

[Dec]

I’m not quite sure if I follow you but did you take the mechanism out of the car as in this picture…
http://forums.mercedesclub.org.uk/attachment.php?attachmentid=4552&d=1201270364
And did you open the motor gearbox as in this picture…
http://forums.mercedesclub.org.uk/attachment.php?attachmentid=4874&d=1206881277

If you have to manually pull the arm back to the park position AND the motor is still running while you are doing this then it is very likely that either some of the nylon gear teeth have striped OR some of the worm drive teeth are damaged inside the motor gearbox as in second link.

Dec

 

[C-Class]

Hi

I didn't open the gearbox, as I thought it was the nylon cog in the wiper mechanism which failed. If I follow, are you saying the mechanism is ok (it looks that way to me) and that the nylon element of the motor could be at fault?

 

[Dec]

Your symptoms have nothing to do with the nylon cog in the wiper mechanism, that part of the mechanism (everything under the “turtel shell” cover) is solely responsible for the in/out action of the wiper blade and is not involved in the sweep action.

The sweep action is driven by the motor through the mechanism so if the nylon gears are damaged the motor can’t bring the blade back to park. The motor is still running because you haven’t switched it off.

The best thing you can do is re-create the fault, that is;
1…When the blade stops at the 11o’clock position.

2…Immediately turn off the ignition and remove the keys from the car. Turn off the stalk switch after you have removed the keys from the ignition. Don’t turn on ignition again until everything is back together again.

3…Open the wiper motor via the 7 torx bolts and ease upwardly the motor gearbox cover, be aware of the electronic components inside the cover. See last picture. You can do this with the motor still in the car.

4…Inspect the nylon gear teeth that are close to the worm drive for signs of damage, nylon shavings may be present in the grease.

5…Check the condition of the worm teeth for damage (broken), look as best you can at the teeth that are not at the uppermost side.

6…Check the condition of the 3 switches, the should all be even and uniformly erect as in picture.

If all is well with the motor then that leaves the fault with either Nut 1 or Nut 2 in my previous picture link.
The mechanism would have to be removed from the car if either of these nuts require re tightening.
In other words the fault could be the motor or the mechanism.

What year is the car?

Dec

Edit; see also pictures in post #17

 

[C-Class]

Hi.

It looks we are getting close to diagnosing the fault. My car is a 1999 C220 CDI. I didn't realise the sweep action was controlled by the motor gears. I will do as you have instructed in your previous post and get back to you. This will have to be after work tomorrow evening.

Your help is very much appreciated. Earlier on when I was dismantling, and putting everything back together again was driving me nuts, as I couldn't see any faults.

If I do have to buy a new motor (much cheaper than the mechanism), then I will no doubt have fun trying to line up the "park" lines correctly.

I will be in touch tomorrow evening.

Thank you again.

 

[C-Class]

Hi Malcolm.

Well, I opened up the motor via the torx screws and lo and behold the inside was full of what appeared to look like fluff. I can olny assume this was what remained of the nylon gear? To add to this there were steel shards amongst this. I also noticed that one of the turns on the steel worm had been worn down to it's base (or had sheared off?)

I ordered a motor from a seller on Ebay today, so I will refit this at the weekend.
I may be back to read the forums on setting this up (parking)

I will also make sure everything is well lubricated and greased before it all goes back together.

Thanks again for your help.

Cheers