I have been working on the rear suspension to improve and work out a few problems.
This post is devoted to resolving a loud thump when the rear wheels fall into a rut in the road. Looking at the rear chassis/suspension leads me to believe that the design is not the best in the world. A small explanation of the design is presented. William Lyons, the creator of Jaguar cars, wanted to have his cars look low and sleek. In order to do so he opted to achieve the low look by passing the chassis BELOW the rear axle. That poses a problem of clearance between the rear axle and chassis. When the car is standing there is just 2-3 inches clearance between the axle and chassis. So if the rut in the road is more than 3 inches deep, the axle will, and does, come into contact with the chassis. This will be clear in the picture below. The green arrow indicates the rear chassis passing below the axle and the yellow arrows point to another area of concern, the limited clearance of cross member to the spring.
In my opinion this is an example of inadequate engineering. Anyhow to counter this, a thick rubber "bump stop" has been provided to cushion the axle as it drops down. Here is a picture of the rubber bump stop. As can be seen the bump stop has collapsed and there is excessive gap between the axle and the rubber indicated by the red arrows. This rubber has deformed to the shape of the axle. It should be straight. Failure of the component was most probably a result of supporting the weight of the axle for 28 years when the car was on bricks.
I believe that the loud thump is the noise generated by the axle banging on the chassis. Bad news is that this item is not available from the usual international parts suppliers.
Faced with this situation, I found a place in Gawal Mandi that can cast rubber foundations. I have ordered a pair of these bump stops. Lets see what they can do for me.....
