Setting up Front Windscreen wiper

[Darren Oldfield]

Hi Dec

Replacement motor works fine. However, to get the correct parked position is tricky. When all parts are lined up flush to markings (as per your previous pics) the wiper still parks in the vertical position. I haven't refitted the whole mechanism yet, just tested it whilst holding in my hand. Have tried a multitude of settings and tweaks (some of which don't even move the wiper at all), but your suggested parked position seems to work best.

The wiper movement is fine, and I suspect it'll all work ok once reconnected, but I'll probably have to settle for a vertical parked position from now on, unless anyone has any other bright ideas.

Cheers
Darren

[Dec]

Hi Darren

First of all, have you parked the MOTOR? turn the wiper on at the stalk for a few sweeps and turn off at the STALK then do the adjustments at Nut 1 to park the blade (Nut 2 should be in position as in picture)
If this doesn’t solve the problem, I have another explanation, but don’t want to confuse you for now. Let us know how you get on with this first.

Dec

[Dec]

The other possible explanation is that you or someone else undid and removed Nut 1, probably to have a look at the gear inside, when the put it back together the park position (of the blade) was moved from where it was before the undid Nut 1.

If what I said in my last post didn’t solve the problem and the blade is still parking in middle of screen, then, with the motor already in the park position proceed as follows:

Undo and remove Nut 1 and anti slip washer and a thick and thin washer.

Remove the “Halve” washer.
(Watch out for any other small, fine washers that may drop to the floor)

Work the hub off the main body of the mechanism JUST ENOUGH for the coged wheel to clear the teeth.

Readjust the hub to the correct park position, then push coged wheel back into the teeth.

Check that the two alignment marks line up fairly close, you can fine-tune the park position at nut 1 before you retighten it.

Note, the “Elbo” should be in the position as in picture.

Dec

[Darren Oldfield]

Dec

I thought I'd replied to this, but can't see it. Wanted to say many thanks for all your help - your suggestion worked (although I could swear I'd already parked the motor in previous attempts). Anyway, it seems the thing to do is to ensure the correct sequence is followed i.e. park motor first, then ensure realignment flush with marks on the casing.

Cheers
Darren

[Dec]

Hi Darren

Thanks for the feedback and glad you got it sorted, it’s a very confusing and a complicated contraption until you get your head around how it all works.

Dec

[Jakar]

Thanks to Dec and all, for these messages. I've successfully fixed the wiper arm on 93 C220 that was resting vertically and passed MOT, and all for free. I have very little experience of mechanics and the worst part is daring to start. The Merc parts come off and back on easily and removing the complete arm was a lot easier than I had feared. The problem was with the conical nut at the back of the motor that loses grip with the un-grooved hole it fits into. I cleaned it with a needle and tightened it up again. I think it stripped the 'thread' (no real thread, just a grip) when it froze in winter and from then on got worse each time it was used. I also looked at the motor head where there is a nylon cog that can wear out. I was scared that when I opened it, bits would all spring out like a Karcher pump but it is not like that. If the cog is worn or broken you could replace the cog easily but Merc don't supply it as a part. You can't just move it round to an un-warn part as there is a set position for the electrics to work. The other great fear was that I might set the wiper to try and sweep right through the car somehow, rather than across the screen! But this is not possible. Works great now, cost £350 last time when the garage 'fixed' it. Dec, you have been toasted with whisky.

[Dec]

Thanks for the feed back Jakar, that’s what causes the fault as you say, if the wiper is switched on when it is frozen to the screen or a lack of lubrication under the “turtle shell cover”, something has to give, either a nut slips and loosens or the nylon gear teeth inside the motor gear box gets striped.

Was that whisky or whiskey, ones is Scotch, the other is Irish, both good lubricants in their own right.

Dec