The rear wheels, differential, and subframe are attached to the car via 4 rubber mounts, 2 radius arms, the propshaft, the handbrake cable, and one brake pipe.No one in their right mind would rely on the last 3 items, and the rubber mounts have a nasty habit of parting company with the steel plates. This leaves us with the radius arms. Whilst these are not designed to keep the rear subframe in place, the additional strain put on the potentially fragile rubber mounts is seriously increased if the radius arms become inoperative for any reason.Whilst it seems that people are quite prepared to replace the arms, due to terminal corrosion and or disintegrating large and small rubber bushes, they tend to turn a blind eye to the chassis mounting plate.
.
Pictures 1,2,&3 show the extent of the rot that may be lurking beneath the rear seat and underseal!
I have owned a number of XJS's and have found dangerously bodged Chassis mounts on all of them. The rigidity of these mounts depends on sound internal sections that are impossible to assess without removing the vertical and horizontal plates. If the outer plates have rotted through, you can almost certainly count on the inner panels requiring repairs as well. A good but not conclusive test is to jack the car up on the rear jacking point. If there are any signs of creaking, or movement around this area, serious repairs are vital. For racing it is even more important, many people extoll the virtues of uprated anti roll bars, but this is pointless if the Radius arm mounts are flapping about in the wind!!! On my car the radius arm had completely come away and there was very little sound metal left. There are not currently any relevant repair sections on the market for the XJS, therefore I had some made.
It may be necessary to remove the rear seat and let a section in. The most difficult part being the seat removal!
Pictures 4,5&6 show the various stages of repair, click on the pictures 3-6 for full screen view.
If your car is pretty crunchy around this area it is worth removing the vertical and horizontal panel so that the internal panels can be inspected and repaired as necessary. The outer horizontal panel has the holes for the jacking support plate and the bushes for correct alignment of the radius arm support bracket prior to welding. The upper and lower jacking plates will have to be removed and re-used. The radius arm mounting can usually be removed and re-used if it has not been continuously welded during earlier repairs. It can be obtained from various dealers part No. JS254.
The plates are produced in 1.5mm mild steel, some cutting and fettling will be required depending on the extent of the area to be repaired etc. These plates are left over from the repairs to my car. They are being sold as a means to substantially reduce the time required to measure up, punch and bend your own panels. They are not authorised repair sections, and therefore need to be installed by a competent person who has the ability to assess that they and other repairs are carried out to MOT standards.
O/S are a mirror image
of the panels shown.
