I have a '96 Vanden Plas. Is there any way to remove the rear lower control arms WITHOUT dropping the rear drivetrain?

 

Ok I'll take a shot at this.

YES. You won't have to remove the differential, drive shafts, or half shafts. But you will have to release tension and remove the springs and lower shock bolts to let the control arms free. You can do this by removing the lower sub-frame plate attached to the bottom of the diff (lowering it on a jack). Spring compressors can be used as an alternative method, but it is not required to use them; just good judgement and procedures to release the springs pressure safely.

Then the control arms can unbolt from the diff (cradle) and the outer hubs, leaving the half shafts in place, which act as upper control arms. Those lower arm bolts are pivot bolts with bearings. Once removed I suppose then the hubs would be dangling at odd angles, still attached to the diff by the half shafts.

Others will add to this or correct me as necessary.

 

I agree with sleekjag. For more detail on the process, look up the threads / Google the A frame method of removing rear springs and shocks. The A frame is the plate sleekjag referred to, and this method allows good articulation of the suspension and safe release of spring pressure.

 

Thanks for your reply! I'm actually changing the rear shocks and the bolt that holds the bottom if the shock in place has seized itself to the control arm due to rust. So I've decided to just replace the arm. However, it looks like the bolt that attaches the arm to the differential, will hit the bottom of the trunk when I try to remove it and not slide all the way out. That's why I was asking if the entire drivetrain needed to be lowered.

 

Thanks for your reply! I'm actually changing the rear shocks and the bolt that holds the bottom if the shock in place has seized itself to the control arm due to rust. So I've decided to just replace the arm. However, it looks like the bolt that attaches the arm to the differential, will hit the bottom of the trunk when I try to remove it and not slide all the way out. That's why I was asking if the entire drivetrain needed to be lowered.

 

I would apply a lot of heat to that seized bolt before removing the control arm….

 

Ahahaha, that is an odd way to do it and faaaaar more difficult and expensive too! You can drop the subframe down and if your exhaust is in good condition it will hold the rest of the rear end just fine, slightly dropped which will allow you to remove both wishbones together holding on the rear wishbone tie. Unless the car lived all its life in a dry and warm climate chances of removing wishbones one at a tine are close to zero as the big pins will be seized solid. The only way to remove them is to actually hold the bolt to either the car and moving the freed wishbones all the way down(car needs to be at least a meter above the ground) or the ground with the wishbones off the car and turning the wishbones around the big bolt, you might need couple extra people to do it with one standing on the tie and second wishbone and the other person standing on the extension bar holding the bolt and you trying to lift the wishbone off the ground to turn it. IT IS THE ONLY way to remove these big bolts, any attempts at turning the bolt and you probably snap it eventually. Only when you crack the rust around it, you can then turn the bolt and wire brush the rust from the middle of the bolt which is visible, after that you should be able to turn it freely with an impact gun and punch it out. These new big bolts are proper expensive, I think they were approx £100GBP each last time I've checked.

If you however just need the lower shock bolt removed and its seized solid, you can simply cut it off at the shock and then punch it out, there is enough space to cut it with a fresh 115mm cutting disc and replacement bolt is £15GBP from Jaguar. Mine was so seized into the shock that no amount of heat would get it out hence why I've cut it off.

If you go the wishbone tie route, consider getting a wishbone tie with the extra ears for the rear anti roll bar AND replace the individual diff dogbones with a monoframe from XJ8, these are one of the best upgrades for the X300 and completely transform how the car drives and holds to the road, they aren't expensive either, just a lot of spannering

 

Don’t forget that changing the control arm will also disturb the trunnion bearings and will disturb rear suspension geometry.
Are you really really sure that shock bolt is seized? Know anyone with an acetylene torch to heat it?

 

this is an easy job if you take it all the way to the ground. use a bigger impact while another dude goes full throttle with an air hammer.

i’ve seen someone do it with the monostrut unbolted so it hangs low then torch. if the car is rusty no chance