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Rebuid or exchange 1989 XJS IRS & suspension System
I have a 1989 jaguar XJS v12 5.3L with automatic transmission & inboard brakes that I need to be replaced. Can the IRS and all of the rear end just be hanging from the swing arms and other parts from the fraim of the car without the hangers supporting the IRS? I was told that the four hanger rods between the car fraim to the IRS are missing when I had the transmission rebuilt. I have the car jacked up and siting on four jack stands. The hight of the jacks are the same but the IRS and everything on it is lopsided. The RH side wheel hub is 15-1/2" above the floor and the LH side is 18", the fenders are both at the same hight 36-1/2". I can only see halfway across the top of the IRS and I do not see any IRS support bolts.
Does anyone know of a company or a person that can rebuilt or exchanged a complete IRS, differential, UJ, new inboard brake system, new shocks, all rubber, bearing, powder coated, ets.? Hopefully a company in the US due to the shipping costs.
There are four mounts, two on each side, that suspend the IRS at the inner part of each wheel well. It sounds like the rubber has failed on at leat one of the mounts on the side that hangs low. There are no "rods" or anything like that holding the IRS in. There are trailing arms of sorts, one on each side, going from mounts on the bottom of the unibody to the hubs. They play no part in holding the IRS in place.
Until you get new mounts, support the IRS at the bottom center under the diff. Do NOT get under the car without that support in place. The mounts i described above sound like they are coming apart, and the IRS could fall out and kill you if you are underneath.
Here's a link on the IRS mounts and their failure. There are videos on Youtube describing how to
take out the IRS.
As Jon has said, get some axle stands carefully under that cage today! There is nothing to stop the whole cage falling out! The radius arms will not stop it collapsing if the four mounts are all undone.
Definitely sounds like the metalastic mounts at the top of the IRS have failed. They're are normally under compression due to the weight of the vehicle. They're not designed for tension loads, especially if they're old and cracked. Be careful when jacking up the IRS that you don't lift the car off the jack stand! Jack slowly to make sure nothing snags. The bottom of the shock absorbers is a good place to put extra jack stands. I routinely place additional support when the car is lifted/
Extra jack stands to support IRS during diff fluid change
Regarding IRS rebuild itself: Depending on what's wrong, you may not need "everything". How many miles? What are the problems? I removed the IRS to fit a rear sway bar. While it was out I did the brakes, resealed the diff and replaced the wishbone bearings. I didn't rebuild the diff, or change the shocks / springs, or replace the U/Js - because they were all in good condition.
Just in case you don't have $5,000 burning a hole in your Pocket
Rebuilding the Cage is easier than it looks and providing you're only intending to replace the Rotors and Calipers, you should have plenty of Change out of $500 and in fact I think I did mine for about £200
A lot depends on your level of enthusiasm as well as the Thickness of your Wallet!
As you will see from the following Post, I build a crude Rig out of Scaffolding Poles, so that no matter what happens, my Car can't fall down as the easiest way to do this job is to take the Cage out altogether
(1) Don't watch the YouTube Videos of anyone doing this, as some of them make it seem like really hard work
(2) Whenever you've got a few minutes to Spare, take the Old Bolts out and replace them with New Bolts, they only have to be finger tight, as they will be coming out again when you do this job for real
(3) Disconnecting the Exhaust is a bit of a PIA Job, so start by changing the Bolts on this before doing anything else
(4) Break the job down into little Steps and just do a bit at a time
(5) Convince yourself you can do it and then plan to do it in stages, one day at a time
(6) The Buzz and Satisfaction you will get from doing this is off the Scale
(7) Make sure to leave enough Space on the Wall for one of Grants famous Certificates of incompetence!
It really no more difficult than Changing all the Spark Plugs! but far more Satisfying
Do the brake disks themselves need to be replced or just pads? Pads are easy, nothing needs to come out for that. If the disks need replacing, then there is more disassembly required.
The thing i'd be most worried about when rebuilding the cage, either yourself or sending it off somewhere....is you suddenly finding other things that need attention. Siezed handbrake mechanism, stiff UJ, pinholed exhaust, oh is that a weep from the axle shaft?...
Then the job snowballs with 'whilst you're there' jobs & you find yourself 6 months later with the cage still sitting next to the car (ask me how I know )
"Then the job snowballs with 'whilst you're there' jobs"
Start from the precept that the rear calipers and handbrake mechs are junk and need a full overhaul, chase the 'it will be OK' from the thought process's.
This little list is mine .... because my rear calipers were seized and the discs a corroded and pitted mess. My handbrake was always poor and I found out on dismantling that the previous person in there had not got the handbrake lever properly pinned - it was floating.
Rebuilt hubs - including hub bearings and pivot bearing replacements - not forgetting of course to properly de gunge and suitably clean / paint / powder coat the hubs, replacing studs as necessary
Rebuilt driveshafts removing grease shields, dismantling and clean / paint / powder coat then install new sealed spiders (no more grease fittings no more grease shields)
Rebuilt differential - including output shafts / seals - rinse and repeat on the clean / paint / powder coat
Rebuilt Brake calipers
Rebuilt handbrake mechs
Rebuilt lower suspension arms including bearings - rinse and repeat on the clean / paint / powder coat
Subframe itself - rinse and repeat on the clean / paint / powder coat
Rebuild the two rear exhaust hangars that hide in the subframe rinse and repeat on the clean / paint / powder coat
Rear dampers and springs - rinse and repeat on the clean / paint / powder coat - replacing the dampers recommended though this can be done in the car quite easily - what can't is getting the springs off the dampers which is pretty damn dangerous - and then are you really going to put those old tired rusty springs back on.
Then re-assemble with multitude of new nuts / bolts and various shims to centre the rear discs in the calipers and then set rear camber,
Replace all brake pipes
Several cases of beer, box or two of Brufen ... save some for the pain when the costs are tallied ....
Now many will say that a lot of these jobs can be done without dropping the subframe - and you can - but having done all of the above I would not recommend it - getting it out is one thing - getting it back together lay on your back potentially working overhead something else entirely different especially when you're trying to get the disc's properly shimmed or lower 'dog bones' back in - doesn't take long for that stuff to weigh as much as the Titanic.
All depends on the ability to go blind and the will to repeat the removal exercise, which isn't actually that difficult if you have a decent transmission jack just how far do you want to or are prepared to go and what are you prepared to un see ,,,
Be under zero illusions the subframe is heavy, you aren't lifting it alone for sure unless you are ranked in the worlds strongest competition.
I didn't really take that many pictures, subframe is back in the car now, I may take one or two more if anyone is that interested
The dog bone's can be seen near top right of this last image. Held them in situ with an engine crane while I coaxed the seals and sundry washers into place - I put the hubs onto the dog bones on the bench before installing into the subframe so they were no fun at all to handle.
Just a suggestion. The IRS is very heavy. I use an ATV jack to prevent tipping of the jack. I routed a piece of thick plywood to fit the flanges / bolts so the weight was distributed over the whole tie plate.
ATV Jack used for IRS removal and refit
Different car - same technique - wood profile shown.
Re-reading the original post - it sounds like the bolts are missing from the metalastic mounts.
After supporting the IRS properly, I'd recommend looking at the car overall and see what else might be missing, especially check the 4 propshaft bolts at the final drive.
When the transmission was rebuilt, did the shop move the IRS to move the propshaft? I don't know about the XJS - but to replace the rear gearbox seal on an E-Type with the engine in place, the propshaft has to be wiggled backwards a bit past the differential input flange. Some people undo the IRS and move it a bit to get the prophaft withdrawn for access at the gearbox end,.
Dropping and refurbishing the cage is a really scary thought, but not such a scary reality. With the right equipment, the correct precautions, and adequate time and patience it can be diy'd by one person. Unfortunately, doing it yourself is the only cost effective option. At this point in time, there is no way to justify to the costs of outsourcing the work relative to the value of the car.
You might find my thread on dropping and rebuilding the cage helpful:
There is a lot of information on replacing the IRS & suspension that I should be able to perform the work. I took the car to get the transmission rebuilt. They said that my *** end was falling off. I climbed under the rear end and lucky I still had the support on the IRS. In looking at the IRS one side both supports are separated and the other side of the car it looks like I have one and a half support still connected. Thank you all for providing this great information from the forum to keep me alive. The IRS is bent up and needs to be replaced. It looks like someone tried to get a 3" exhaust or just a new curved pipe through the IRS. The installer must have also used a sledgehammer on the piping that is all bent and crushed. Ihave a few questions regarding what parts should be replaced and with what manufacturer and part numbers. I would like to install a new stainless steel Bell exhaust system. What is the largest Bell exhaust that will fit through the IRS? I was hoping to install one CAT, no muffler, a 2-1/2" straight pipe to the IRS, curved pipe through the IRS, install a resonating box and the enlarged version of the original tailpipe. Do you think the car will be to loud? I have an aston Martin and I don't want the Jag to be louder than the DB9. I hate squeaking brakes. I don't need high performance brakes and tires. I am only driving the convertible when it is sunny, above 50* on mostly dry roads. I will be using the car as a grand touring car and cruising up to 120 mph. What brand and part number of brake rotors and pads should I install? Should the calipers be rebuilt or replaced? I have the inboard brakes which I would like to keep original. I will be replacing all of the break lines and installing stainless steel flexible hoses to the calipers. Is there anything else that should be upgraded for the braking system? I will try to attach a couple of pictures.
It is a shame that there are hacks that would think it’s okay to do stuff like that. Replacing the rubber mounts is easy, can be done without disconnecting the propeller shaft and brake hoses by dropping the assembly just far enough to fit the mounts.
Replacing the rear crossmember might be the easiest, but you really don’t know what you’re getting with a used one. The cage is fairly light gauge sheet metal, and the area where the exhaust passes is non- critical; I would be tempted to try and straighten it. Or get a used assembly and rebuild it before swapping out yours.
I have stock exhaust on mine so can’t help you there, but there are actually 3 catalysts per side, two are close coupled to the manifold flanges, and the third where the two join (per side).
That is interesting that you have 3 CATs on each side. My car had 2 CATs on each side. One at the manifold and one where the piping goes horizontal then it goes to a muffler before it gets to the IRS. Due to the age of my car emission testing is not required. I could eliminate all CATs but I decided to keep one on each side incase someone decided to look under the 5" of car clearance.
09-27-2024, 03:00 PM
Rebuid or exchange 1989 XJS IRS & suspension System
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