MG Tech – Classic MG Windscreen Washers

Windscreen washers are an item that few people check on a regular basis – but they suddenly become very important when it’s time for the MOT, as an inoperative washer is a failure item.

On MGs there are normally two basic types, the older mechanically operated system worked by a push button mounted on the dashboard and from the early sixties electronic pump units commonly activated using a switch on the end of the wiper stalk.

First thing to check if the screen washers don’t appear to be working is that there is actually fluid in the reservoir and that the tubes are free from blockages. Older systems use a bottle, while later installations feature a bladder located on the inner wing which, while saving space, is often more difficult to clean.

Next make sure that the spray nozzle or pair of jets aren’t blocked. Regular waxing of the bonnet around the nozzles can leave residue that hardens if not properly cleaned off. There are specialist cleaning tools but a sharp pin inserted into the jet will normally do the trick or the unit can be dismantled and thoroughly cleaned. A new jet costs between £3 and £4. While doing this ensure the angle of the jet is correctly positioned onto the windscreen.

If this fails return to the reservoir container and examine the condition of the fluid. Over time this can turn to a jelly that as well as blocking the feeder tube can also harbour nasty germs. Replace old fluid with a clean mixture at the recommended strength.

At the same time check the filter at the end of the tube that goes into the bottle – remove this and make sure it is clean – wash in clean water. A replacement filter costs between £1 and £2.

On mechanical systems another potential problem area could the in-line non-return value which is normally located close to the pump behind the dashboard. This can be detached along with the dashboard pump, cleaned and checked by placing it in a bowl of water.

If the mechanical pump is not working properly – it uses a rubber diaphragm that can perish – a replacement costs under £10.

The non-return value and filter on electrical systems are located inside the bladder and need removing to examine for condition.

Electrical systems use a small sealed electric pump which is located under the bonnet. If this appears to be the problem ensure that it has a good live feed and that the terminals have not become corroded.  The unit can be double checked by removing it and linking it direct to a battery – if it doesn’t appear to work it could be the impeller inside the pump that has failed – a new pump costs around £14.

More seriously the fault could be in the wiper operating lever itself – a new arm will cost between £20 and £30 depending on model, if unsure get an expert to check it and fit a new one for you.