Quick question to which I think I know the answer !!

I am going to replace my rear subframe support brackets which are very rusty and corroded. I have a new pair sent all the way from Arizona where I guess it never rains (or is that Southern California ??)

If I drive the back up on ramps, so the car is sitting on it's wheels, can I just unbolt the brackets (one at a time) and replace without anything falling around my ears ? I assume so, but would like confirmation before getting the spanners out.

(I have already released each bolt individually, so am confident there won't be any problem getting them off the car.)

 

The 'A' Frame should drop when the bracket(s) are removed as they are what hold it in place. However, when I've done 'A' Frame bushes, it's taken some persuasion to release them so you could find it just stays in place. Nevertheless, a jack under the frame would be a sensible precaution.

Graham

 

Rusted right through from the top, couldn't see it from the bottom


Looked solid enough down here.


All prettied up and ready to go back in.

If your brackets are that rusted I would be checking the rest of the sub-frame for corrosion damage. When I first got my car 3 years ago I thought I would refurbish the rear end as a winter project. It looked solid enough but I wanted to clean it up, put in new bushings and shocks and make it pretty. I was very surprised when I dropped the sub-frame to see the serious corrosion that was not apparent from below. Granted mine is a Canadian car so has probably seen some snow and salt in its life before me. I would suggest poking around a bit in the areas I have pointed out in the picture as they were rusted right through. I got it welded up, sand blasted and powder coated should be good for a long time.

 

Daro31 - Thanks for that. I have just had some welding done on the rear sills and rear chassis to celebrate my car's 20th birthday !!
I'm confident that the rest of the sub-frame is OK - admittedly the original powder coating on the springs has started to come away, and there's superficial rust in a few other places, but overall, I think I got there just in time.
One of these days, I would like to drop the whole rear assembly as you have done and totally refurbish, but for the time being, I'm just trying to keep on top of any gradual deterioration.

 

Although I have neither the time nor resources to remove the whole of the rear subframe and get it in the superb state that Daro31 has achieved, I have decided to replace the two A frame bushes while I'm under there with the spanners.

Any advice as to whether to stick with the Jaguar original rubber bushes, or can anyone recommend the Powerflex / Polybush polyurethane type items ?

I know there's a slight cost difference but other than that ????

 

Again, I am not answering your real question and I put the Jag OEM bushings in mine so I can't speak to the performance of anything else. What I want to tell is that it took an arbor press to get the old ones out, and to put them back in. Perhaps they will go in when you bolt it back up, but they were tough to remove. I even cut them up to get the old ones out, but that would be tough to do from under the car while the rear end is still in place.

 

Hi DD,

There is no way to change the subframe bushes in situ so don't buy any new ones just yet.

If you need to change them the the subframe will need to come out.

As for a simple bracket change, here is my how to.

*** ALERT *** if you buy new fixing bolts, be very careful that they are the cottect pitch, Jag solf me a packet with the correct part number on the packet but with the wrong bolts inside.

https://www.jaguarforums.com/forum/x...ackets-166019/

 

No - sorry - I didn't explain myself very well.

I will be removing the "A Frame" with the bushes. I have a replacement from a breakers which is in good condition so will give it a clean, wire-brush, rustproof, paint etc and replace the bushes - even though they look pretty good - before putting it on the car in place of my original, and I already have the "new" brackets which, like RaceDiagnostics - I had to source from the US.

I am pretty sure I can do this without removing the complete sub-frame assembly with my fairly basic tools and old-man's-back !!

I have loosened all the bolts so I'm confident none will shear off or cause me any additional major problems. They are all in good condition so I will re-use them with a good splodge of blue threadlock just to be sure ! I know Jaguar say use new ones, but they are expensive and providing the originals are OK, I can't quite see why that's necessary.

I can get a friendly garage to push new bushes in and the costs difference isn't an issue so it's just a straightforward question - original Jaguar rubber, or pretty yellow Powerflex ????

 

Hi DD,


Like others have said - the whole rear subframe needs to be removed if you want to remove and replace the large bushes. I replaced mine with Polybushes (yellow ones) which require a lot of cutting, chiselling and hitting to remove the old rubber buses. The new polybush ones are 'push fit' but require some effort (picture my wife jumping up and down on a piece of plywood on top of the bush whilst I check alignment as they move into place!).


I think the brackets can be replaced at each side independently - so unbolt the bracket and jiggle off whilst the other side remains instiu. I seem to recall actually that if both brackets are removed, (car up on stands etc) that because the subframe is fixed to the diff and the diff to the car mounting points via the pendulum - that the whole lot only moves down slightly without the brackets. It is advisable however to have a trolley jack underneath just in case!


cheers

 

kg7657
The breaker from whom I got the "new" A frame assured me that it is possible to remove the A Frame without having to remove the complete rear suspension. He told me that, with the car up on ramps (so weight on the rear wheels) and a jack under the A Frame, I could unbolt the two brackets.
Then, with all the A Frame bolts off, I could gently lower the jack and, with luck, the A Frame would drop down with the rear suspension a short way, and then separate from the rest of the rear suspension which would be held up by the other attachments at the rear. His view was that the greater problem might be that the bushes refuse to come away from the rest of the suspension and that's where a big pry-bar might be required.

As you say - "the whole lot only moves down slightly without the brackets" so if the A Frame is not attached to anything else, it will just drop down a bit more slightly when the jack is lowered !!

 

Well - that was easy !!

Cut the centre of each bush out with an ordinary jig-saw. Pointed a blowtorch at what was left until it was burning merrily. Once it had pretty much burned out - took about 15 minutes or so - I could remove the remains of the bushing with a couple of light taps with a hammer and drift.
Total time for both sides ( including 15 minutes tea break while the fires were burning - 1 hour.
Wouldn't recommend this indoors, or if you have sensitive neighbours - the black smoke is a bit toxic and probably illegal !!

 

Well done DD - yet another way to do a similar problem! I also like the sacrificial fire to the great God of rubber bushes. Sometimes our cars are really easy to repair and I can appreciate the engineering that has gone into them - other times things are very different.


cheers

 

Yes - but - unfortunately the same great God of rubber bushes won't allow the same trick when it comes to inserting the new ones !

It's more about hydraulic presses and quite probably a lot of un-jaguarlike foul language !!