Squealing And Slow Rear Wiper Mechanism

[Parrot of Doom]

The rear wiper has been getting slower and noisier of late, enough to cause concern. So today I pulled as much as I could to bits to see what's up.

Getting to the motor and mechanism is easy enough, just remove the large piece of plastic (held in with clips) at the base of the rear door, disconnect the courtesy light, and the gearbox is right in front of you. Three 10mm (ish) bolts to disconnect the covering plate from the door, and four cross-headed screws to remove the plate from the gearbox. Only grease and friction holds the gears in place so beware of falling bits. There's a black lead to ground the motor, it won't work without that connection so if you try to operate the wiper while it's in pieces, nothing will happen.

Everything looked in remarkably good order, totally clean grease, pristine plastic, all as you'd expect. So after removing the gears to see where the friction is, it seems to be entirely on the spindle that connects directly to the base of the wiper arm. And there my troubles begin, because I don't have a puller tool to disconnect the wiper arm from its spindle. It's extremely stiff and won't simply pull off by hand. I suppose I could tap the gearbox out by hitting the spindle from the outside, but that's just inviting calamity... Looking behind the plastic seal from outside, the spindle looks fairly corroded so I'm guessing that it needs a good cleaning out. I suppose it could also be the motor, but I don't see why that would suddenly get weak.

I can't force it with a lever because it's parked on the rear window (don't want to crack the screen). Anyone done this job before and got any tips? Else I'll just give it to the mechanic to sort out when it goes in for it's 90,000 service (which is now due).

[katabrontes]

You could try using a piece of thin ply with a slot to cover the glass around the spindle and then after a bit of penetrating oil on the spindle you should be able to lever it off. I expect the service , if it's Lexuxs may shock you when they bill you for a new wiper unit.

[MURPHYBEAR]

Hi Parrot

I bought my RX300 with a seized rear wiper. I told the vendor and he arranged to get a new wiper motor under the 3 months guarantee.After waiting a while I fixed it by removing the wiper as you have and removed the gears from the wiper gearbox.

I then grasped the output drive shaft away from the end with Mole Grips and rotated it back and forth. It eventually moved and then I introduced oil then kept it moving until it was a smooth movement. This was in October 2014 and it is still working.

I never got my new wiper under guarantee. I was quoted £50 from an online breaker for a working one but MAKE SURE you get the correct unit i.e quote the serial/part number to the breaker over the phone/via email.

Best Wishes

Murphybear

[Parrot of Doom]

Thanks, I don't think it needs any new parts, perhaps a bushing or two, but everything else seems good. Murphybear, what contains the output shaft? Is it a bushing or something? I have a feeling that if there is one, it's stuck or torn or something. After all, that's the only (slightly) exposed part that'll see rainwater and dirt. I just need to prise the arm off the spindle.

[steve2006]

There has to be a shaft seal to prevent water running down it into the motor/gearbox, have you considered some WD40 down the shaft and allowing it to penetrate overnight then trying the wiper?

[Parrot of Doom]

Trust me, it's beyond simple lubrication. Something is either badly corroded or broken and needs to be replaced,

[MURPHYBEAR]

Hi Parrot

The output shaft is held in somehow. I couldn't see how to take it apart. I baulked at forcing it apart as I didn't have a replacement, but the output shaft where it enters the gearbox housing was rusty and corroded for about an inch along its length.This is what I gripped with my Mole grips.

I suspect water had been entering the bearing and laying for some time to corrode the shaft. The motor seemed to stand up to being powered, and not being able to run, very well.

I wanted to get it working for the winter.

Hopefully Colin Barber will have an input.

Sorry not to be more use.

Murphybear

[Parrot of Doom]

Well it seems that 4 days parked in an airport car park following a good dose of oil down that shaft has cured the problem.

[MURPHYBEAR]

Hi Parrot

Good for you. I don't use my rear wiper for long periods - perhaps I should. I'm afraid it'll seize up again. Did you manage to get it apart in the end?

Best Wishes

Murphybear

[Parrot of Doom]

No, didn't manage it. But I advise other forum users to lift the rubber seal at the base of their rear wiper to check for corrosion. If the shaft looks messy, get a few drops (no more than that, it has to go somewhere) in it, just in case.