As the Jaguar XK8 ages, front suspension parts are expected to wear out and require replacement. Typically wheel bearings, upper and lower wishbone bushings, springs, shock absorber ball joints, etc. they will eventually require replacement.

However, if your car’s front suspension is making a knocking noise, don’t necessarily assume it’s caused by one of the above and shell out loads of cash to replace one or more of these parts. A rattling sound from the front suspension can be a much more serious problem to solve.

This could be caused by the upper yoke bushings getting stuck on the steel fulcrum pin. The combined seized unit then wore down on the car’s aluminum subframe and created an oval-shaped pinhole. When this happens, the wheel and suspension become unstable and tend to float with excess play. Obviously, this will manifest as a deterioration in handling and increased road noise (cluck).

It’s not hard to understand how this can happen when you look at the poor design of the upper wishbone, bushings, jack pin assembly and Jaguar area. At each end of the pin hole, the pin is recessed and allows water, dirt, salt, etc. enter the bore and corrode the bushing and pin. No protection is provided for the exposed area or indeed Jaguar Maintenance recommends regularly cleaning and protecting the area with grease or wax.

The tops of the front and rear hub are designed to self-lube and rotate as needed around the fulcrum pin. However, when these corrode, the seized combo unit wears down on the aluminum subframe. To make matters worse, an electrolytic reaction can occur caused by the passage of the steel pin through the aluminum subframe and steel bushing inserts.

If the subframe wear is excessive, this may require a complete replacement with a new or used known-good subframe. A new XK8 subframe part will cost over £1500 to replace. A much lower cost solution would be to have an experienced engine engineer add new subframe inserts and then replace the pin and both bushings. As of adding this article, I don’t know how successful the latter approach has been.

I have checked my XK8 car for play and corrosion in this area and everything seems to be working fine. I have completely protected the bushes, pin and general area with waxoyl. If I hear knocking in the front suspension, this will be the first area I’ll check.

Finally, if you’re working on removing parts from the XK8’s upper wishbone assembly, then perhaps it’s more cost-effective to replace all the bushings and ball joints, even the springs and dampers at the same time, as they will inevitably need to be replaced in sometime. in the future and the completed work will contribute to improved handling, quietness and enjoyment of your car.