Removing Tailgate Wiper Arm S204, Help Requested!

[Chrishazle]

Attempting to fit a replacement blade to this beastie I managed to break the little plastic clips that holds the blade to the arm, so sourced a replacement arm and a Neilsen CT1785 battery terminal/wiper arm puller, gave the drive shaft a little penetrating oil while waiting for everything to arrive.

This morning I've removed the locking nut from the shaft - fairly easily - and been trying to remove the arm. Given it lots of good quality penetrating oil, got the puller properly mounted, about every half hour for 2 1/2 hours now I've tried tightening the puller as much as I can, loosened it off, squirted more penetrating fluid and left it to soak. Still no movement of the arm coming free on the shaft!

Other than continued 30 minute soak and wait, the only other thing I wonder about trying is, with the puller on and tight, switch the rear wiper on for 1 wipe - but not sure if that might overload the motor.

Any other tips for getting this beastie off? TIA guys and dolls!!

Chris

 

[Chrishazle]

Just a quick update - the arm is still attached, the puller has managed to shear one side of the plastic over the arm bushing, it's wet and dark so I've given up for the day and am seriously thinking of taking my Dremel to it when the weather clears! I did try 1 wipe of the wiper - did not help.

 

[Chrishazle]

After much swearing and cursing I finally managed to replace the rear wiper arm - major soaking with good quality penetrating oil and a proper puller failed to shift the old one, so finally resorted to the Dremmel and a fine cutting disc, cut a 5mm piece out of the plastic surround which freed the plastic part of the arm, with that out of the way I cut a 5mm piece carefully out of the old bushing and the puller got the rest off. Cleaned everything up with a brass wire brush on the dremmel, then put hi-temp ceramic grease on the shaft, installed the new blade onto the new arm, refitted and locked on with a new SS nylock nut, then covered all that with grease!



The replacement arm and blade are not genuine MB - eBay special for £12.99 delivered instead of £50+ for MB. Blade is 1cm shorter than the replacement Bosch blade I bought a while ago (breaking the little plastic securing clips on the arm when fitting it, hence replace the arm!) and the little plastic cross bar in the blade that locks into the clip is larger than the Bosch, which would not clip in. However, it works!

 

[mattkh]

Well done.
I was going to suggest using a crow bar to push it up from under, but that would have put a dent in the tailgate.

 

[Chrishazle]

I watched a couple of Youtube videos before starting this job, hence the purchase of the puller. Apparently it's quite easy to damage the motor assembly inside the tailgate if you get heavy handed with the arm and shaft - something I did not fancy happening. I was reluctant to turn to the Dremmel, but after most of yesterday and half of this morning squirting penetrating fluid on the shaft every 1/2 hour, including leaving the tailgate partly up so the shaft was vertical, my patience ran out!

One interesting point I discovered - the threaded top part of the shaft only extends to the top of the bushing, below that is a tapered spline that gets wider downwards - not by a lot, and it's not obvious when looking at the new bushing that the hole at the bottom is fractionally wider than the hole at the top!

My other big tip is install the new blade with the arm off the car - that way you can see what you're doing, whereas with the arm on the car it's virtually impossible to see the little clip part and get the crossbar in the blade in exactly the correct position.