Wiper

nosmo-king

A little info please..
How do I get the wiper arm to rest at the bottom of the screen on a mercedes. When its finished its wipe it stops about six inches from the botton.
Any ideas ...

colm_mcm

the gearbox that controls the wipers' extendable arm is knackered. It'll need a new one, rumoured to cost around 800 quid. Very common on old C Class.

crosstownk

You could try remove the wiper from the spindle and refit it in the correct position - might work.

If the wiper has never been removed before then it's a bit odd and you could be into the scenario that colm mentioned.

colm_mcm

Moving the wiper arm won't work. When the gearbox needs replacing the wiper will rests approx 6 incles above its normal position. when you turn the wiper on, it goes down 6 inches, then wipes normally, then rests back 6 inches above where it should. If you move the arm, it will just hit the scuttle panel and damage the arm.

crosstownk

colm_mcm wrote:

Moving the wiper arm won't work. When the gearbox needs replacing the wiper will rests approx 6 incles above its normal position. when you turn the wiper on, it goes down 6 inches, then wipes normally, then rests back 6 inches above where it should. If you move the arm, it will just hit the scuttle panel and damage the arm.

In that case I'd say the OP should start by looking in a scrappers - but if these things fail regularly then it might prove hard to locate a second hand one.

colm_mcm

It's not that hard to live with after a while. nice Touring Car look!

TychoCaine

I had a similar thing happen my Focus after getting a snapped wiper linkage replaced by the local ford dealer. In the Focus the arm on the motor is supposed to be at a specific angle when connected to the linkage. The "mechanic" didn't check and bolted it together any old way, with the result that wipers swept the full screen as normal, but stopped 1/2 way up the screen.

When I queried this they claimed that the motor must have been knackered when the linkage snapped, and a new one would cost $$$, plus another $$$ in labour. I said I'd look after it myself thank you very much and took it home and got the spanners out. I took it out and re-did it correctly and it's worked fine since.

I know the cantilevered arm on a Merc is slightly different, but it might be just as simple as disconnecting the motor from the gearbox, winding the gearbox on to the fully down position and bolting the motor back in.

colm_mcm

Mercedes is a single extending arm wiper setup, so different to Focus. As far as I know, simply winding the motor on doesn't work.

TychoCaine

The cantilevered single wiper is different to a conventional two wiper linkage, but the principal is the same. This is what the mechanics looks like (it's for a 90's C class, but they're all the same):

The arm I'm talking about is #4 on the picture. Unbolt it from the motor, wind the arm so it's at it's lowest point, and then bolt the arm back onto the motor. Job done.

Gary

colm_mcm

It's usually a broken mechanism that causes this symptom though. I asked merc mechanics before when it happened.

nosmo-king

Thanks for all the help folks
I understand a new wiper motor was fitted recentely.
Maybe... it just wasnt set to its proper position......maybe

colm_mcm

hopefully!

MercMad

This is normally caused by lack of lubrication of the shaft that extends out to reach the top corners of the screen., This shaft should be regularly ( twice per year) lubricated on all Mercs with a single wiper, otherwise it will get stiff, slow down, seize up and eventually strip the motor pinion or burn out the motor if it stalls for too long.

I have repaired many of them by doing what is suggetsed above, but also lub the shaft. Even if the pinion has stripped it is possible to disassemble the entire area and mechanism and repair, I've never had to replace one yet, but if you've to take it out its a bitch !

Hopefully it sounds like it just needs to be synchronised properly, but be careful here, and always ensure you have the keys in your pocket before working near a wiper meachnism, its very powerful and can cut your fingers off very easily !

crosstownk

MercMad wrote:

always ensure you have the keys in your pocket before working near a wiper meachnism, its very powerful and can cut your fingers off very easily !

Excellent advice. About 10 years ago, while I was working on a wiper fault on an Audi A3, I left the keys in the ignition switched to 'on' with the wiper motor disconnected :rolleyes:. After reassembling a few bits and pieces I reached in under the wiper linkage to reconnect the wiper motor which activated instantly :eek: and almost chopped off my left index and middle fingers - I was lucky as I ended up in Tallaght Hospital with 3 stitches in each finger. The cut was so deep on my index finger that it grazed the bone. Lots of pain and blood, but thankfully I still have my fingers. It was simply down to my own carelessness.

Once again - excellent advice.

nosmo-king

Thanks for all the helpful advice.

To reset and lub. Is this a job for a mechanic or is it something I can do myself. I dont have a workshop manual for this car so do you know the disassembly / assembly procedure. Are there any special tools required.
How long SHOULD it take to do.
Thanks in advance

Lucifer

can also agree with the advice of removing the keys! nearly took off my finger before while setting up a linkage with the first year apprentice, i was pointing to something to show him and i didnt realise that the wipers were still on intermittent. caught my finger between 2 parts. was very sore!

nosmo-king

Will keep key in pocket ok.
Please see above ....can I do this myself.

nosmo-king

Any ideas