Time to start on the rear suspension. The Jaguar unit was removed from the cage and new mountings fabricated. The first being a crossmember to bolt in the diff housing. Then various mounting points to hold the IRS unit in place. It is to be solid mounted requiring a number of brackets and location arms to be made. These hold the diff so it does not move at all. The suspension can then move independently, a very well engineered system. Developed over many years by Jaguar. A system that has been used many times for all sorts of modifications to Hotrod and kit cars in particular.

These next series of photos show the unit still in the cage (trimmed a bit) just setting up for height and the get the position right.

And then crossmember being made to fit and then a mounting plate to bolt to the top of the Diff. This mounting point as per original design.

Crossmember has been cut and trial fitted in place on the original chassis.This will be welded in place when all fabrication is done and checked for correct placement.
The diff is still in the cage at this stage, checking angles and ride height.

Diff propped up on timber blocks and mounted on plywood “wheels” to simulate the correct ride height.

New crossmember and mounting bracket, checking for height and correct angle.

Centre mounting bracket for the top of the diff. This was fabricated and welded to the new crossmember. The material used was 100 * 50 * 6 RHS. the bracket made from the same material

Diff now removed from the standard cage and the new bracket bolted in the original position. Wheels fitted to test the position again. The body needs to be fitted at this stage to check again for correct position, both ride height and within the wheel arches.

The body fitted temporarily, the height is close to where it should be. And the wheels look good in the wheel arches too. The front suspension also is looking all right. There may be some slight alterations needed later but for now all is coming along well.
We can now remove the body again and continue with the fabrication of more new location brackets.
The wheel fits well in the wheel arch with these tyres. They will be replaced as they are too old to be used. But for now they are perfect while the chassis modifications are being done.

Next the bottom of the diff needs to be bolted in place so it cannot move. So some brackets were made to hold the bottom suspension arms in place. Along with a modified plate for the underside of the unit.
These photos show the making of the brackets and fitting in place. Progress now with the diff in place and the chassis rolling again.

This is the bracket made for the rear of the diff mounting. When the unit is in the original cage it is bolted in these places. So when taken out of the cage the diff must be supported at the same points. There is a bracket needed at the front and rear and also a plate to go across the bottom.

These units have been mounted by others using the cage and original rubber mountings as well. But we prefer this way as it gives better access to service the brakes and has a much better appearance.
This being an important consideration for this project.

So front and rear brackets made and fitted now to connect these to the Chevrolet chassis.

There are three main mounting points for these units. One to the top of the diff itself as seen above. One ( actually two ) at the front of the unit from the bottom of the diff out to the chassis rails. These are to counter the torque reaction. To stop it twisting. And the third ( another two ) to hold the bottom suspension arms from moving backwards and forwards.
These all have to be fabricated to mount from the original points and to connect onto the Chevrolet chassis.
All this will make the Ute handle much better and improve the ride. It should be as comfortable as a modern Jaguar and handle as well. Not to mention the upgrade of the braking system and steering.
But more of this later as there are a lot of pieces to this puzzle.

Next we have brackets to weld to the chassis for the torque reaction rods.

And the actual arms bolt in place between the diff bracket we have made and the brackets welded to the Chev chassis

Then there are two radius arms that reach forward and hold the IRS unit and stop it moving backwards and forwards under braking and acceleration. The position of these is critical and we need another new crossmember for the mounting brackets. This one goes in between the rear unit and the rear of the gearbox and will have extra bracing stiffen the chassis.

New crossmember brackets and bracing.

Radius arms fabricated and bolted in place

The chassis needed some extra stiffening and to help this the new crossmember was fabricated with bracing added to it. This also serves as a point to mount brackets for the location arms and was placed so that the arms are mounted correctly. These location points are critical to ensure the suspension works as Jaguar designed it. With no binding or additional stress on the components as it moves through the whole range of movement on the road.
There are specific measurements for these attachment points. All these will be checked by the ASRF inspectors at the first inspection of the modifications.

These pieces all being in place the last components if the IRS are the shock absorbers and springs. These are coil over shockers and there are two each side. We need to fabricate the top mount to connect to the new crossmember made previously.
The bottom mount is on the bottom suspension arm as originally done by Jaguar in the factory.
This first photo shows the bracket being tested for fit and shows the shock units bolted to the bottom arm ready for test fitting.

Once the height is checked we then make a temporary bracket to bolt in the place of the shocks. Again to check the ride height is okay before everything is finally welded.

You will note that the parts are just tacked at this stage and some still are to
be cleaned and painted. This will all be done when the fabrication is finished and has passed the first inspection.