Jaguar XJ-S. Manual — part 97

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adjusted by replacing shims between the inner end of the axle and the brake disk. The more shims put in, the more the
top of the rear wheel tilts outward.

Note that there are usually some shims between the brake rotor and the differential unit. These are to locate the rotor
properly between the calipers, but also affect the camber as well. If working in this area, always make sure all shims
are reinstalled properly. If your objective is to relocate the brake rotor without affecting the camber, move shims from
inside the rotor to outside or vice versa, but do not add or subtract any shims to the car. If your objective is to alter the
camber without relocating the brake rotor, add or subtract shims from outside the rotor and do not disturb the shims
inside the rotor.

Randy Wilson offers this advice: “Camber is not a constant. The camber control is taken on two pivoted arms (of
unequal length) so that the camber can change on a predetermined curve based on suspension position.

“It is very unlikely for the camber to change from factory specs unless one of three things happens: either something is
bent, someone left some shims out during a differential or brake service, or the ride height is wrong. The #1 cause is
the last, sagged rear springs. So, when you are told that the rear camber is off, investigate the static ride height before
investing a lot of time/money in shim swapping.” Better advice: don’t make any decisions about adjusting shims
without ascertaining the alignment properly, which means to lock the suspension height using the specified tools; see
page 355.

CLUNK - REAR: See the section on page 351.

REAR SUSPENSION SUBFRAME/DIFFERENTIAL REMOVAL: To work on the differential, as well as many
tasks relating to the rear brakes, it is necessary (or merely preferable) to lower the entire rear suspension assembly out
the bottom of the car. Fortunately, this is nowhere near as difficult as it appears. It is suggested you read through the
tips on removing the inboard rear brakes starting on page before starting this job.

The basic idea is to put the rear of the car on jackstands, position a floor jack under the center of the IRS, unbolt it from
the car, lower it and roll it out from under the car. The first challenge: You need to get the rear of the car high enough
to get the suspension out from underneath. To get it out the rear of the car, the lowest point of the bottom of the trunk
needs to be higher than the height of your floor jack when fully collapsed plus 13”. Plus an inch for fudge, just to make
sure.

As soon as you get the car propped up and the rear wheels off, the next thing you should consider doing is removing the
grease fittings at the bottom of the hub carriers. They’ll get busted up sooner or later if you leave them in there.

The next challenge will be getting a jack that can get high enough to hold the subframe up while you take the mounting
bolts off, and then lower it far enough to get out from under the car -- which means a stroke of 13” or more. If your
jack isn’t up to the task, Jan Wikström says “You’ll need to shift the subframe in two lifts. I use a 5” thick wooden
block on the jack and rest the unit on two cement blocks halfway up.”

“You need a friend to stabilise the subframe as you move it down and up (and help you lift it to the workbench; that
sucker is heavy). To make the job a lot easier, take the spring/shock units out first and refit them last.”

When ready to lower the IRS, Jim Isbell describes locating the jack: “Make sure it is under to the point of almost being
too far forward. The cage will try to roll forward if the jack is too far back as it is front heavy.” The balance point
appears to be perhaps three inches forward of the axles.

Some owners have reported good results with putting the wheels back on during removal; that way, the assembly can
be rolled out from under the car. It will require positioning the car on even taller stands, though. Disconnecting the
spring/shock units from the lower swingarm first helps because it allows the suspension to squat.

Note that the suspension assembly, standing on its wheels, will show a distinct tendency to roll over. If you try to keep
it from rolling over by holding onto the radius arms, you may find that the radius arms can swivel around their
attachments to the lower swingarms without warning and the assembly rolls over anyway, probably onto your toe or

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some such. John Napoli suggests “let it flip upside-down. Now you can wheel it anywhere you like, wheelbarrow-
style, using the trailing arms as handles.”

If you’re going to position the suspension assembly upside down -- either during this rolling or later when working on
it -- you might consider capping the vent on the final drive unit so you won’t leak oil everywhere.

If you can’t get the car very high, the suspension assembly may need to come out the side rather than the rear. If you
position something with wheels under each hub carrier and lower the suspension onto them, you can then pull your
floor jack out the rear and roll the suspension out the side. Bob Gallivan says, “I dropped it onto my creeper on one
side of the center of the diff & a moving dolly on the other side. Worked like a champ. Rolling it out the side is the way
to go.”

Craig Sawyers suggests you don’t use the kids’ skateboards, though. “My thought exactly the first time I tried this.
Miserable failure; totally unmanoeverable - works like two independent bogies. Impossible for one person to handle,
and requires an act of coordination beyond anything mere mortals can achieve if two try it. Complicated by the fact
that the top of the board is resiliently mounted to the wheels, so it tilts in wierd and unpredictable ways.”

Of course, just using the floor jack from the side instead of the rear might work. Sawyers: “I found just balancing it on
the head of a trolley jack and rolling it under the car worked just great.”

When several members of the online discussion lists tackled IRS removal, there was a lot of discussion of details.
When the smoke cleared, it turned out that several of the problems discussed were related to the XJ saloons rather than
the XJ-S; the IRS is identical, but a couple of detail differences apparently cause consternation when removing the IRS
as a unit.

The first issue discussed was the need to remove the stainless steel exhaust tips, apparently because they protrude
through holes in the bodywork on the saloon. Removal is one of the steps listed in the Haynes manual as a precursor to
removing the rear mufflers themselves. On the XJ-S, there is no problem here; you can leave the tips on if you want
and remove the rear mufflers with them attached. In terms of repair manual correction, this means that Section 28 of
Chapter 11 in the Haynes manual should include a note that Step 2 of Section 27 can be omitted in XJ-S work.

The next item was what to do when the rear mufflers won’t come off! If the pipes won’t come apart at the forward end
of the rear mufflers, the obvious solution is to remove the rear mufflers with the IRS. Again, removal of exhaust tips is
necessary on the saloon and not necessary on the XJ-S -- but you might choose to remove them anyway to keep them
from getting dinged up. Jim Isbell explains this procedure with the saloon: “It is complicated greatly if, like me, you're
not able to remove the tail pipes because it's then necessary to slide the cage forward as it drops so that the tail pipes
will drop free in the rear. As the cage goes forward it hits the front exhaust pipes and the drive shaft so those have to be
kept out of the way.” David Littlefield points out that none of this is a problem with the XJ-S: “The cage will just drop
straight down, the muffler/pipe/tailpipe combination won't hang up on anything.”

“This combination is best left in the cage until it is on the bench. Then disconnect the lower fulcrum pin from the
shocks and push down the axles. This will allow removal of the pipes without too many contortions. Replacement is
reverse of removal. I put the whole rear muffler/pipe/tailpipe assembly back into the cage before refitting to the car.
The mufflers actually provided some leverage to wrestle the whole thing around. It helped to temporarily hang the
over-the-axle pipe on its rubber mounts to keep the mufflers from dragging around and from accidently falling out.”

The next issue involved exactly how to disconnect the mounts holding the subframe to the car along the upper edge of
the wheel well. There are four mounts, two on each side, and the questions involve whether to unbolt the mounts from
the subframe so they stay on the car or to unbolt the mounts from the car so they come away with the subframe.
Littlefield explains: “In my correspondence with Jim Isbell, we determined that it is difficult to get at the rear mounting
bracket to chassis bolts (two in each bracket) on the XJ6 and that the Haynes manual recommends removing the
suspension cage to mount bolts (three on each bracket) instead -- but just on the rear. On the XJ-S, I had no problem
getting to the bracket to chassis bolts on all the brackets. Not a big deal, but I think it might be a bit easier moving
things around if the bracket to chassis bolts are the ones undone.” On the saloon, Isbell seems to feel that it is important
to unbolt the forward mounts on both sides before working on the rearward ones; on the XJ-S, it’s hard to see how the
order would make any difference.

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Franck Guilloteau says, “I believe that there is one important step that need to be added before dropping the cage.
Loosen the nuts that hold the half shafts to the differential. If yours are as tough as mine were when I did the camber
change (first time), removing them with the cage off is no fun exercise. I forgot to do it the second time when I
dropped the cage. Fortunately I hadn't removed the hand brake calipers and was able to use a long pipe clamp to
compress the calipers and stop the shafts from rotating. Even with anti-seize compound it was no picnic (air tools did
help though). If you have removed the brakes. well good luck!!

“Using a 20" extension and 11/16" deep socket (not to forget the long pipe to use as leverage at the end of the ratchet)
you can remove/loosen up 3 of the bolts that hold each half shaft (remove the u-joint cover and rotate shaft until you
can get to the nut - use the hand brake to stop rotation). The 4th bolt which has a zerk fitting in the way so you need a
shallower socket. It should come last in the removal sequence.” Of course, you might opt to temporarily remove the
zerk fitting to get the socket on the nut.

Littlefield: “Or, you can put an open-end wrench on the nut, turn the drive shaft until the end of the wrench contacts
the cage and stops the drive shaft from turning. Then take a breaker bar or other long lever and turn the hub by using
the lugs. With that kind of leverage, the nuts should break away pretty easily. It is a good idea to put the lug nuts on to
prevent damaging the threads. I own an impact wrench and an air compressor, which helped, but there is one nut that is
under a zerk fitting and I used the above method for it.”

GETTING THE RADIUS ARMS OFF: The ©1975 ROM, section 64.35.28, step 4, describes disconnecting the rear
anti-sway bar link from the radius arm. Most XJ-S’s don’t have a rear anti-sway bar, so you can skip this step.

The point where the front end of the radius arm attaches to the lug on the bottom of the car is a notorious spot for
difficulty of removal. There’s usually a goodly amount of rust involved. Mike Morrin describes his preferred method
of removal: “I have found that the "no muss, no fuss" way to break the bushes from the body involve the use of a lever
or pry-bar with the end shaped so that it will go through the hole in the bush, allowing a lot of leverage between the
inside of the bush and the mounting thingy on the bottom of the car. I tried most of my (extensive) collection of C
spanners in this role, and found a BSW spanner which looks about 60 years old, and has just the right curve on the
outside of the C that when one jaw is poked in through the hole in the bush, the outside of the C makes contact with the
thingy. The spanner handle is pushed upward (maybe encouraged with a BFH), and the bush just pops off. Because
the joint is tapered, it seems you need to apply enough pressure to start to deform the inner ring of the bush before it
will move.”

Miles Milbank offers an alternative method: “Remove all the pertinent fasteners. Place a small hydraulic bottle jack on
top of the radius arm and unscrew the jack's adjuster to contact the underside of the subframe mount and jack it up until
the large rubber mount is well stretched. Spray liberally with Liquid Wrench or other penetrating oil from all sides,
including inside from underneath where the main bolt was extracted. Walk away and do something else for awhile
until you hear the assembly pop apart, and the bottle jack crash to the floor. Repeat for other side. If it doesn't work
within an hour or so, one can come back every so often and apply a bit more: 1) penetrating oil 2) jack pressure and,
finally, 3) a few helpful taps at the fitting to encourage it to give way. One time I have hooked a slide hammer to the lip
inside the fitting where the main bolt had lived, and the most stubborn radius arm immediately came off.”

John Napoli describes a method that works for him, but note that it involves removing the entire rear subframe: “The
car should be supported by 2 jackstands at the rear lifting points. Get the cage ready for removal: brake lines,
emergency brake cable, exhaust pipes opened (exhaust pipe(s) in front and the resonators in back -- the over-the-axle
pipes can stay in place). You don't have to remove the driveshaft -- it will pop at its slip-joint. If your car has a two-
piece shaft, remove the plate holding the carrier to the unibody.

“Place your floor jack under the cage. Remove the safety brackets and main bolts holding the trailing arms to the
unibody. Don't try to remove the trailing arms, though. Remove the bolts holding the cage to the unibody (the four
rubber mounts). The mounts will stay on the unibody for removal/replacement later if needed. Lower the cage so the
weight is on the trailing arms. You want 'a lot' of the weight of the cage on the trailing arms, but not all of it.

“Take your air hammer, and put a blunt chisel in it. Place the tip of the chisel between the trailing arm and the body
(you and the air hammer are standing perpendicular to the car -- you do this from the side, not underneath!). Let the air

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hammer rip, not enough to cut the metal, just enough to vibrate things a bit. The trailing arms will pop off as nice as
you'd please.”

If you intend to remove only the radius arms and leave the rest of the subframe attached to the car, you might be able to
modify this procedure and make it work. If you disconnect the radius arm at the swingarm first and find a way to pry it
downward, you’d be applying essentially the same loading to the attachment.

Obviously, during reassembly it’d be a good idea to use anti-seize compound on this connection to make it easier to get
apart next time.

REAR SPRING/DAMPER DISASSEMBLY: The obvious way to disassemble the springs from the dampers on the
rear end is to remove the damper with the spring installed, then use a spring compressor on the bench to separate them.
However, Ian Macfarlane provides an alternative procedure: “To change the rear shock absorbers without using a
spring compressor, the springs can be held in the compressed state by fitting four elongated “C” shaped brackets (two
per spring) over the centre 80% of the spring with the car jacked up under the suspension (preferably with a load in the
rear of the car to maximize spring compression). Then, when the car is jacked up under the body, the springs will
remain partly compressed and the shock absorbers can be replaced relatively easily.”

REAR WHEEL BEARINGS: Justin Pashley says, “A couple of weeks ago I posted a message asking for opinions for
what could be causing the rumbling noise coming from the rear of my car. Initially I thought it was a wheel bearing but
after jacking up all the wheels none had any excessive play. Well, everyone who responded said it most probably was
still a wheel bearing, even though there was no play. I have now had the rear wheel bearing changed and yes, the noise
has gone! So, to anyone else that has a rumbling rear end with no play in the wheels, it is probably a wheel bearing.”

Martin Lappin agrees: “I've had cars that sounded like the diff was toast, no play at the wheels, but change the bearings
and everything was quiet!”

Tom Bernett concurs: “Several years ago I had a rear wheel bearing go on my '87 XJ6 SIII. I didn't feel any extra play
in the wheel. But, if I remember correctly, I was able to determine it was the wheel bearing by spinning the wheel
while listening with a stethescope on the hub. Compare sides and I think you'll be able to tell if one's bad.”

Jerry Holloway reports, “When I disassembled the drive shafts from the diff and could turn them, it became obvious the
outer wheel bearing on the left side carrier was down. Interesting that it didn't show itself until I was able to turn it
freely parted from the diff. Showed no extra end-play or anything (couldn't feel it with it turning the diff. either) but
man was it starting to grind.”

Interestingly, if you do have play in the wheels, it might not be the bearings! See below.

According to Chad Bolles, the bearings in the rear wheel carriers are a Bower/BCA part number 18590-18520 for the
inner, and 18690-18620 for the outer; available in any auto parts store.

Getting the old bearings out is always fun. Jim Schultetus says, “A neat way to remove the bearing cups is to weld a
bead around them with an arc welder or a mig welder. Let it cool down a bit and they will fall out as the weld bead will
shrink the cup as it cools. Freeze the new cups and tap in.” Not sure I’d go this way in aluminum housings; use at your
own risk.

REAR WHEEL BEARING SLOP: I was thinking of adding an illustration here, but cannot think of how to draw this
so it’ll make sense. There is an exploded view in the Parts Catalogue and there are a couple of cross section views in
the ROM but neither makes it too clear how the stack goes together with shims to establish the proper end play in the
bearings. I have decided that a wordy description is probably best.

The stub axle, which is the section of the rear axle from the outer U-joint outward, has threads on the end where a
“Jesus nut” (so called because that’s what you’ll be saying if it comes off!) threads on. This is the item shown in