EXTRA THOUGHTS ON Q&A

I have just got to the troubleshooting section of the April issue, and have a couple of comments that might be of interest. Firstly, the Austin 1100 front wheel bearing issue. The reply you gave is all good of course, but my experience can add a couple of other potential causes. The large hub nut gets tightened to a very high torque, and few DIY people have a torque wrench of that capacity. If it is not tight enough, it works loose very quickly. The tapered washer behind the nut gets damaged, and if not replaced, will cause the issue to recur in a short time. (I once encountered a nut that had been tightened with a chisel – I'm not sure how one gauges the torque applied that way! That took out bearings, hub, flange, CV joint and brake disc.) Another thought is that with Minis mostly, but also some 1100s, people fit wider wheels, or wheel spacers. This moves the pressure centre out from the centre of the bearings, leading to rapid wear of the bearings. Spacers should only be used to use wider wheels and keep the centre of the wheel over the centre of the bearings.

Turning now to the Volvo 740 timing belt, whilst the method of loosening the crank pulley bolt with the engine starter can be effective, care should be taken with newer vehicles. To eliminate production tolerances and enable accurate camshaft timing on modern engines, many lower timing belt pulleys are not keyed to the crank, merely held by the torque of the pulley bolt. Using the starter to loosen this can allow the crank to turn without the camshaft, with expensive results. I was called to assist someone who had inadvertently left a spanner on the crank bolt and tried to start a Peugeot 307 2.0 petrol engine. We had to lift the head and replace all the exhaust valves. Oops.

Great advice Nigel, thanks – Ed