X300 Rear Bumper Brackets that corrode

Replacing the Rear Bumper Brackets (also affects the XJ40)

The rear bumper mounts are often the cause of a thumping sound at the rear of the car and is frequently accompanied with a lop-sided bumper. The mounts are made out of a tough plastic with a metal adjusting collets located at the rear end. The mounts then fit directly to the body shell via four bolts (two of which hold the rear silencer brackets in position). There is also a thin rubber gasket - which must be replaced. A long central bolt with a drop spacer fits through the rear bumper outer casing and cross member up through the adjusters and into captive nuts in the cross member itself. To do this job you will require the tools and parts listed at the end of this article. Failure is often found to look like the pictures below.
To remove the bumper follow these steps 1.     Remove both of the tail pipe trims. 2.     Undo the two 19mm long bolts that secure the bumper to the mounts or if they are as bad as the ones shown it may well pull off but you don't really want to try that. 3.     Once removed slide the bumper backwards with the help of an assistant gripping ether side and the rear. If reverse sensor radar is fitted unplug the connectors to the sensors in the bumper. 4.     Move the bumper assembly to a safe storage area away from the car and stow it in a manner in which it will not become damaged. 5.     remove the four (per side) 13mm serrated nuts from the original mounts and remove the mount form the car noting the exhaust hanger bracket orientation before doing so. 6.     Clean off the old gaskets from the car and discard. Reassemble is the reverse of the above. Noting the following:
The adjusters need to be set to allow a gap of 5mm when the bumper is refitted between the lower lip of the valance and the top of the bumper trim this equates to a gap of 38mm from the top of the adjuster collets to the valance lip as shown below.
The picture below shows the correct arrangement of the bolts and spacers prior to reassembly. It is important that protection of the metal surface is given consideration to prevent your new ones from rotting.
Tools: 13mm Spanner (open and offset ring) 13mm Socket 19mm Socket, wrench and 100mm extension arm Stiff brush for cleaning away mud Anti corrosive compound and a water resistant lubricant. Parts: Rear mounts x 2 M8 Serrated nuts x 8 and washers x 4 Long bolts (special Part) x 2 Spacers x 2 Gaskets x 2