Page created: 20-Aug-06

Re-published: 1-Nov-09



Technical: Discovery I
Rear Wiper Motor

A little while ago my rear wiper motor seized partway through a sweep across the screen. It didn't come as a complete surprise as it had beeInside the gearbox of the seized wiper motorn running slowly and haltingly for some time, which is why I didn't think the problem was electrical, but as it's not something I use every day I'd basically ignored it.

When it ground to a halt this time, I decided to open it up and see what the problem was, and this is what I found. The gearbox was a mess of what looked like rust and the plastic teeth on the main gear had been all but worn away. There is a reasonably snug fitting plastic cover to the gearbox but it seems it hadn't been sufficient to keep out Moroccan dust, which had combined with the grease that should be in there to form a very efficient grinding paste. The unit was dead. I couldn't even get the gears to move, let alone separate them to attempt to clean them properly, so the whole thing was consigned to the bin.

Shiney new wiper motor with a nicely greased gearbox!I ordered a new motor from Dingocrofts which arrived a couple of days later. It's worth noting that the motor comes complete with the mounting bracket attached, but without the mounting bolts or the nut on the driveshaft that secures the wiper arm, which must all be retained from the old motor.

I opened up the gearbox of the new motor to see what it should look like. I then took the opportunity to smear a little bit of grease around the edge of the cover before putting it back together again in the hope of preventing a repeat failure.

Removing and re-fitting the motor to the rear door is very straightforward. With the trim removed (in my case a chequer plate panel) the motor can be seen in the centre of the door. It's held in place by two bolts - one at each end of the integral supporting bracket - and a large nut on the driveshaft where it protrudes through the door skin. With the wiper arm removed, these three fixings can be released and the motor taken out through the hole in the inner door structure. There are two electrical connectors attached to the motor which must also be released.

Refitting the new motor was just as simple although it's worth connecting up the power and running it before putting the wiper arm back on to make sure it's in the proper park position.

It's worth noting here that the rear wiper will only operate when all the doors are shut!