I am in the process of fixing a barn kept Hess & Eisenhardt Jag in wonderful condition except...the tires were all rotted and as I jacked up the car the rear suspension did not move. This is my first Jag so every thing is"foreign" to me. I noticed the way the cage is mounted to the body and I wonder if by my raising the body, in typical American car fashion, did I tear the mounts apart? I also noticed the former owner, who was in the process of replacing the engine with another Jag v-12, was working on the back shocks and had one side finished and the other side partly done. How can you change the shocks without jacking the body up? Also, how can you change the exhaust without raising the body and having the rear suspension just hanging there? As you can tell I am in a quandary! HELP!!!
Schoe

 

OK to jack the car up by the body....use the jacking pegs, in fact....they're visible below the rocker panel.

Not sure about the suspension not moving but it doesn't have anything to do with lifting the car by the body

Cheers
DD

 

I have the Jag on jacks but the mounts for the cage are completely ripped apart. The metal mountings are fine but the rubber that holds the mounts together have torn free from the mounts. I do not want to put new mounts on and have them come apart...unless mine were just old. They are the original mounts (23 years old and 86000 miles). The only thing holding the rear suspension to the vehicle is the drive shaft, at least right now.
Schoe

 

that happens quite often , i have had it happen at least twice, it is poor engineering , without any plan for future of the vehicle.

i jack them up by the center of the cage, or one side under the lower suspension point.

even if mounts are good jacking by the body mounts, take a look at the stress on rubber mounts.

and on fronts i jack at the sub frame front points.

 

on fronts, you can jack at lower spring seat, need a low style jack tho.

 

These rear subframe mounts never really lasted long, but when the rear suspension was designed, (1960s), cars lasted a whole lot less longer anyway, so the mount life was regarded as acceptable. Of course we now expect cars to go to Mars and back, but these mounts are no better now than when they started, so it can come as a surprise when they fail on what we now consider to be low-mileage cars.

Replacing these mounts is not difficult, (I replaced them on a 1980 XJ6 around 1990 and had no trouble with the job), and they are not expensive. Do make sure, however, that the subframe assembly does not drop out accidentally, so use something to support the subframe in the middle.

If you are replacing the subframe mounts, it will be worthwhile replacing the rear radius arm bushes as well, and also checking the trunnion bearings on the hub carriers - make sure they get some grease, there is a nipple at the bottom of the hub-carrier, a lot of people forget it is there, and even put the jack there and break it off ! In fact grease everywhere you can see a grease nipple - the UJs have them too, as well as the inner, lower wishbone bearings.

As regards the shocks, they are like motorcycle units with the spring around the shock as a bolt-on unit, prepared off the car, then bolted back on. Easy to take off and put back on, a doddle, in fact. You will need a spring compressor, but the type used for McPherson struts should be OK.

The exhaust is in several sections, all replaceable without dropping the subframe.

So you see, Jaguar engineers of the 60s really did think about the poor maintenance mechanic ! To me this classic Jaguar independent rear suspension is a work of art. The only thing not to like is the inboard mounted brakes, they are a real nuisance for servicing. Jaguar moved these outboard on the very last of the XJSs in the early 90s, long after the Series 3 saloon had gone out of production.

 

Thanks to everyone. That is the type of data that I needed. It also dispels the fear factor of screwing something up when trying to fix it. While I have your general attention, when I first checked the vehicle out, to make sure the engine was not frozen, we put a battery in it and turned over the engine. It turned over fine with no trouble. A few minutes later we noticed smoke slowly rising from under the car. We hurried to unhook the battery and the cables were very hot. At first I was thinking it had a dead short in it but if that was the case it would have sparked when we put the battery in the car and when we took it out. Could it be a short in the starter which is an enormous amp draw, or is it something else? I need help on this one. By the way, it is not the original engine. The former owner pulled the old one (blown head gasket) and dropped a 92 XJS engine in it after changing over all the Lucas electrics to it. The guy was an expert Jag XJS restorer so I tend to trust his work. Nonetheless...anyone have any ideas????
Schoe

 

check your GROUND cables, the big flat ones under left lower side of engine, maybe even replace.
ijust bought an xjc, for low money, because no one seemed to figure out electronic probs.

cables visual inspection looked good, but a good yank on one and it pulled apart, so i replaced all heavy grds, no more probs, except for replacing a lot of small elecs. that burned out from bad grds.