Stop my daily grind
QThe final drive of my Humber Sceptre is making a dreadful grinding noise on the over-run. I’ve replaced the axle oil – but it didn’t look particularly dirty. Where do you think the problem lies? Arthur James, Reading
AWe suspect the pinion bearings in the ‘nose’ of the unit have worn, putting the crown wheel and pinion out of adjustment. Rectifying this can be annoyingly longwinded. After replacing the bearings, the pinion may have to be re-shimmed to put it into the correct position for silent running in all conditions.
The cheapest fix is likely to be a complete secondhand lowmileage final drive unit. First, though, try removing the propshaft from the axle to reveal the pinion nut on the input drive flange. It may be loose due to bearing wear. Release the locking tab and do it up firmly handtight and no further. Refit the locking tab. This may subdue the problem for an indefinite period.