SERVICING REAR WIPER MOTOR

[NigelA]

The water feed for the rear window goes through the wiper motor. There has been a problem getting water onto the window and it appears that there is a blockage (maybe rust?) in the feed path in the motor.

Have obtained a repaclement motor. It is impossible to blow through so presume this may be blocked as well.

Has anyone taken one of these motor units apart and, if so, what advice do they/you have please?

TIA

[Brianmoooore]

The backplate comes off the gearbox easily enough, and you will see that the water path is very simple.
There is a rubber O ring seal in the bit on the back cover that leaks and fills the gearbox with water. This in turn rusts the steel plate that in most motors is used to park the wiper, but in this case is used to control the washer so that it works when the wiper is going in one direction only.
Simple cure for this is to connect the wire to the sliding brush permanently to earth. The washer will then work in both directions.
There is possibly a one way valve built into the bit on the backplate.
Similar Bosch wiper motors can be found on Montego estates and Ford (IIRC) Sierra estates, which possibly may supply a few spare parts.
Are you sure the washer motor is running?
If not it's probably the rusty plate I've mentioned above.

[tourer-dan]

My rear washer was all over the place.
It turned out to be a combination of rear wash wipe relay, knackered pump and blocked pipe.
Take the pipe off the connector on the motor, then push some electrical wire (5amp) through from the jet end. Keep poking and the rust and sludge should come out the back. you might need to flush a few times in between, but it will clear. Check you have water flow by running the pump with the pipe disonnected from the wiper motor. Check the pump by substituting it for one of the front motors. The relay should simultaneously wash and wipe on pressing just the wash switch, and the water should flow only on the upsweep of the wiper, even if you hold the switch continuously.
Smear some vaseline around the pump seal in the bottle when reassembling with a NEW seal to prevent getting your tool roll wet!

[NigelA]

Thanks, gang, for your helpful comments.

Have now taken the back off the replacement unit and there is a shaft attached to the wiper (connection) side which fits into a rubber sleeve - this might be tapering, on the back-place side.

At any rate there appears to be a recess just behind the end of the shaft which may take a small O ring: This area was black rusted although there was no signs of water inside the casing.

Once having gentlly removed the black rust was the time when it appeared as though there was a recess for the (probable) O ring. The channel through the shaft was blocked from that end and poking brass wire through quickly cleared the way.

The question is where can one obtain an O ring that small. Do Halfords do a box of different sizes, for example?

When I have this all sorted out I am contemplating putting some sort of anti-rust additive in the washer bottle. So is there some product that can be used this way and yet not foul up the cleaning solution for the window?

Brian. Your comment about the one way valve. I think that is the in-line device immediately on the water supply side. And if that's the case there would be no need for one inside the unit.

Question also - how are pics attached to the postings please.

Thanks again in advance for any helpful comments.

[Brianmoooore]

Brian. Your comment about the one way valve. I think that is the in-line device immediately on the water supply side. And if that's the case there would be no need for one inside the unit.

Yea you're right. I was trying to picture the set up in my head, being to lazy to walk out to the workshop, and I couldn't picture a non return valve.
Try a motor factors or a plumber's merchant for the O ring. I know my local Plumbcentre keeps a box of O rings under the counter.
If you find one, assemble it with plenty of silicon grease.

[NigelA]

Thanks, Brian. Good idea; plumber's merchant for O ring.

Silicone grease - yes. But what about trying to prevent future corrosion? Or could it just be a matter of periodic checking?

Nigel

[Sjoerd320i]

Thanks, Brian. Good idea; plumber's merchant for O ring.

Silicone grease - yes. But what about trying to prevent future corrosion? Or could it just be a matter of periodic checking?

Nigel

clean and prime the corroded parts if possible should stop it from corroding again

[NigelA]

Thanks, Joe. Your illustrations suggest two cracking cars.

Nigel

[KDS]

This is probably a dumb question, but is rear wiper motor damage most typically caused by washer fluid flooding the unit or is it from rainwater? Can I prolong the life of my wiper motor simply by draining the reservoir and never ever using the washer jet?

[NigelA]

I will wait to see to what others, and probably much more experienced, say. However my thoughts are that you will need to disconnect the rear wash bottle pump because I don't think it does it any good to run dry, which it will otherwise automatically do.

If you are not going to use the wash (and why wouldn't you?) then I would still suggest taking the backing plate off the motor and ensuring the end of the water supply shaft (previously mentioned) is clean and that the water passage is clear. Then grease the whole thing, just to be sure.

The other thing is that atmospheric dust and general dirt will build up on the window and also rest on the top side of the wiper blade. This stuff is abrasive and 'running dry' is only going to make the action of the wiper etching this stuff on the window worse.

[KDS]

The other thing is that atmospheric dust and general dirt will build up on the window and also rest on the top side of the wiper blade. This stuff is abrasive and 'running dry' is only going to make the action of the wiper etching this stuff on the window worse.

The only time I really use the rear wipe is to clear away water while it's raining, which is plenty often here in Vancouver. Fear not, I'd never drag a dry, dirty blade across my new rear window. Ouch! In my car, the left button activates the intermittent wiper without pumping washer fluid; I never touch the right 'wash/wipe' button. But is there anything wrong with letting the reservoir run dry?

[Brianmoooore]

Yes, the "check" light will flash and low washer fluid LED will light, unless you short out (or open circuit -can't remember which), the level sensor.