Rear wheel centre bushes appear to be badly worn. they are not engaging with drive gears hence self drive not working. Is any person aware of replacement bushes for drive wheels. Scotland UK

JM, May 2012

If you have a manual, there should be a helpline number. If not, look up 'bearing suppliers' on Google. The bushes (plastic or phosphor bronze) will be a standard size. If not, a local engineering firm should be able to make a couple of bushes for not too much money - probably better than the originals.

Phil Saunders, June 2012