REAR AXLE PROBLEMS

Recently in the workshop we have come across more back axle problems than we ordinarily see. As crown wheel and pinions and half shafts are amongst the most expensive items of the SEven to replace, I remind you of a few precautions to avoid hefty bills.

Firstly, of course, regularly check the axle lubricant level which should be up to the filler hole. On many cars the filler sits on the back end of the unit and when removed just beyond the threads lies the crown wheel. So unless you are careful when injecting the lubricant, it has a habit of bouncing off the crown wheel and coming back out of the filler hole giving a false impression of the axle being full.  On many models it may be easier to jack the body to gain easier access to the filler plug.

Often heard when a Seven is moving off (for or aft) is a clonk, seemingly from the back wheel area. Nine times out of ten this means the half shaft taper is loose on the hub and, if left, at the least you will break the half shaft key or at worst the shaft. Keep the big hub nut up really tight - we use a 2 foot gas bar. Willie McKenzie at ARP does a useful tool to stop your hub turning whilst either tightening the nut or removing the hub.

The torque tube anchor under the centre of the car has a habit of juddering when you pull away. There are 2 tightening adjustments:  the yoke ring and the fixing to the chassis (except on late cars), but ensure that you do not over tighten it as the anchor must be able to pivot. This can also be greased from inside the car by removing the inspection cover between the seats. Earlier cars have a nipple but on  late ones you can remove the bolt and add a nipple.

Finally check your torque tube flange nut is tight and your universal joints are in good condition and lubricated where possible.  On early cars keep an eye on the condition of the fabric coupling on the front end of the propeller shaft.

Gary Munn. GM Autoservices/ Munwellyns