R129 1994 wiper mystery

[Dec]

Blade parks on driver side on UK car.

Using your picture above and if there were no alignment marks you would do the following;
=Remove the right side bolt and lift off the short arm beside the ball joint

=Plug the motor into power and run it for a few seconds
=Switch off the motor at the stalk switch, the motor is now parked
= Unplug the motor
=Slacken off the left bolt but don’t remove it from its shaft

=Loosen the arm at this bolt with the screwdriver like in above picture
=Move the wiper arm to where you think it would rest in its park position on the car.
=Reattach the short arm beside the ball joint

=Reposition the other side while keeping the wiper arm/hub where it should be parked on the screen
=Retighten both bolts
=Test on car

Dec

 

[Watchcame430]

Ok, thanks ... Will have another crack. I am leaning towards that cog though. The turtle thing is just not pulling in quite enough or early enough.
It's so strange..

 

[Dec]

It’s definitely the cogged wheel slipping on its shaft, put in a lollypop stick or it will continue to hit the windscreen side trim.
This coged wheel has no bearing on where the wiper blade parks, that is down to how you adjust the left and right bolts, i.e. NUT 1 & NUT 2 mentioned in my picture.

There will be a part number, perhaps hidden by levers, on the mechanism.
See also... Mercedes Wiper Mechanism | R129 SL | eBay

Dec

 

[Watchcame430]

I am concluding the same. Will buy another ... It's a third car so can live without it for a while. Shame though ... I wanted to fix it.
Thanks for all your help! Will have to fit the stereo instead this weekend.

 

[r129 300sl]

Hi

Had a similar problem. Ended up getting a second hand unit from the US on ebay. New is almost £1000 from dealer here.

Managed to get one from Texas so hopefully hasn't been used much. Of note it appeared to be from a later car so the wiring was different. I think the control mechanism is more modern electronic than the early cars. We had to modify the donor loom somewhat to match it up to the car (1990).

 

[Watchcame430]

Hi

Had a similar problem. Ended up getting a second hand unit from the US on ebay. New is almost £1000 from dealer here.

Managed to get one from Texas so hopefully hasn't been used much. Of note it appeared to be from a later car so the wiring was different. I think the control mechanism is more modern electronic than the early cars. We had to modify the donor loom somewhat to match it up to the car (1990).

Did a left hand drive mech fit?
I only need the mechanical bits anyway ... Pretty sure my motor is fine.

 

[rorf]

Great to see the detail that Dec has gone into explaining the mechanism of the wiper system - that's what makes these forums so fantastic.

Thanks to Dec

 

[Dec]

If you buy one from a left hand drive car make sure you see a picture of the mechanism, as it might not fit your right hand drive.
Your existing motor will fit so no worries about electrics.
Part number is the best guide.

Dec

 

[Watchcame430]

If you buy one from a left hand drive car make sure you see a picture of the mechanism, as it might not fit your right hand drive.
Your existing motor will fit so no worries about electrics.
Part number is the best guide.

Dec

Getting one from a RHD but read LHD was different.
I have the part number from Merc and going check what came off.
Wondering if the later version might fit as its easier to,service withe the flip off cover.
I agreed to buy an early mech yesterday and the seller has disappeared. Hope to hear today or the hunt will continue.
I will take the one I have apart again and see if i can make the shaft spin in the cog to,be sure but it is likely that is the problem.
Having taken and refitted it now more than 10 times in 24 hours I think I can refit it in about 3 minutes!

 

[Dec]

It’s possible that the newer version would fit, it would all depend on the mechanism fixing bolt hole locations matching the old with the new mechanism exactly and if the 3 motor bolt hole locations/size are compatible.
You would really need to have both mechanisms in your hands to make the comparison.

If you jam the mechanism with a lolly pop stick then that will solve the problem of blade hitting the side of the windscreen.

The remaining problem is getting the blade to park at the bottom of the windscreen when you switch off the wiper, that’s all down to how you adjust the 2 nuts/bolts on the back of the mechanism. Remember to park the motor before any adjustments are made.

• Parking the motor means turning the motor on for a few seconds and then turning it off AT THE STALK SWITCH and allowing it to finish its cycle, i.e. park.

• Parking the wiper blade/arm means the adjustment of both nuts/bolts on rear of mechanism so that the blade is at the bottom of the windscreen, driver’s side.

If the blade is not parking where it is supposed to then it’s only an irritation, it won’t do any harm to the system, it will just annoy the hell out of you.

Dec

 

[Watchcame430]

Thanks Dec,
Guy just came back to me on the part ...i am using a matching early one.
He says it is good so fingers crossed!
I know what you mean about the lollypop but i dont need the car so will wait and fit a new part.
Lovely day anyway so going for a drive!

 

[r129 300sl]

Hi

If I remember correctly the new one from the US fitted correctly into the mountings. No adjustment was needed. It came as a complete unit with motor and even the wiper blade. The only modification was the wiring.

I still have the old one somewhere..

 

[Watchcame430]

An update ... Thanks to Dec I came to the conclusion the small cog must have been spinning on the shaft. Probably because it had been straining for a while having not been regreased by the previous owner.
Me stripping it down had make it run smooth but damage had been done to the small cog.
I bought a replacement mech and greased that up. Then made sure the motor was in park by turning it on as directed above.
Bolted it all together and problem solved!

 

[Dec]

That was quick, glad you got it sorted. Hold on to the levers section between the hub and the motor as the ball joint can wear out, it can’t be replaced so worth keeping this part of the mechanism as a spare.

Dec

 

[Watchcame430]

Thanks, will do ... Going to keep the whole lot in case I strip the gear part too.
Was good to get it done quick but a roof problem now!
Loving the car though ... So much so I am thinking about buying another ..