Jaguar XJ-S. Manual - part 113

 
 

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to ensure the pins won’t loosen during thermal expansions, and even if it was, this is not a good place to rely on simple 
bolt tension to ensure nonrotation.  The handbrake calipers are rotating around these pins; if they develop a little friction 
in that pivot, they can be trying to forcibly unscrew the pivot pins!  This assembly calls for a positive retention feature 
of some sort.  Lock washers or Loctite are better than nothing, but we are talking about brakes here, do you want to take 
chances on something that might hold? 

Regardless of whether you buy a kit or assemble your own vented rotors, the lower swingarms may contact the wider 
discs during assembly.  This must be corrected by some minor grinding on the arms themselves.  The problem is 
obvious; bolt the rotor to the output flange on the diff, try to swing the lower swingarm up into place, note where it hits 
the rotor, and grind metal away from the swingarm until it clears.  This doesn’t seem to cause any problems -- this 
swingarm has plenty of strength to spare! 

Chances are pretty good that your exhaust system looped through the rear cage very close to the bleed screws on the 
calipers -- and you just moved those bleed screws 1/4” in the wrong direction.  You will find it helpful to disconnect the 
exhaust pipes at the adjustable joint just ahead of the IRS and at the front end of the rear muffler and realign them from 
scratch.  If you have the older style assymetrical exhaust pipe supports within the cage, as discussed in the ROM 
Section 30.20.02, you should install them the opposite way as shown in that section in order to position the exhaust 
pipes farther outboard by about a half inch.  Reportedly later cars have a symmetrical support, so it won’t matter which 
way it is installed. 

When installing the pads, install the new longer pins in the upper end of each caliper from the inboard side outward.  
Installing the other way may make them difficult to remove later because the exhaust pipe is in the way.  Install the pins 
in the lower end of the caliper from the outboard side inward, since the nose of the differential will prevent installing 
the other way. 

This entire vented brake rotor upgrade is documented in photographs at 

 

http://www.jag-lovers.org/xj-s/book/InboardBrakeUpgrade.html

 

 

MORE SERIOUS REAR BRAKE UPGRADE:  The rear brake upgrades mentioned above involve a set of spacers and 
other small parts to reassemble the OEM calipers wider to fit the wider vented rotors.  Alternatively, any of several 
high-performance brake manufacturers could provide a completely new rear brake system, complete with fancy racing 
calipers -- all of which would obviously cost more.  However, if your calipers need rebuilding or replacing, you need to 
add the costs of repair to the costs of the upgrade kits before comparing to the cost of an entirely new brake system. 

 

RETROFITTING OUTBOARD BRAKES:  When the Jaguar XJ-S was raced competitively, sometimes the inboard 
rear brakes were relocated to outboard (whenever such modification wasn’t against the rules, of course).  The move to 
outboard seems a bit odd since theoretically inboard should be the better configuration from a performance standpoint, 
but apparently there were at least two other factors involved.  First, the inboard location is prone to getting oil on the 
brakes, either dripping off the differential or being blown back from the engine compartment.  Second, in any race 
longer than a few hours, a heavy car such as a Jaguar will probably need to replace brake pads during a pit stop -- and 
having to replace inboard rear brake pads will result in a long pit stop indeed. 

Moving the inboard brakes to outboard makes some sense to the everyday driver, too.  It will certainly make brake 
service easier. 

If you feel the need, it shouldn’t be too difficult to retrofit the outboard rear brakes from the XJ40 or mid-90’s XJ-S to 
the earlier cars.  A cursory inspection of the rear hub carrier from an XJ40 indicates it is a bolt-on retrofit to the XJ-S 
suspension.  If you don’t have ABS, just leave the sensors out.  Chuck Sparks says that this retrofit may require the use 
of the XJ40 axle assembly, though.  Or, perhaps just the outer stub shaft -- but Sparks says the U-joints are different, so 
mating them up might be difficult.  Just grab the entire axles while you’re in the junkyard. 

Note that when the XJ-S went to outboard rear brakes, it was first fitted with solid rotors, and later upgraded to vented 
rotors.  You might prefer to pirate parts from a later car with the vented rotors. 

 
 

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Retrofitting the outboard brakes should actually make the rear end of the car ride a hair higher, since it is taking the 
weight of the brakes themselves off the rear springs and putting it directly on the tires.  There also may be a slight 
difference in the center distance between the outer swingarm pivot centerline and the hub centerline, with the XJ40 
being about 1/4” shorter -- which should also raise the rear ride height by about 1/4”. 

Obviously, after all this fiddling is done, you’ll need to realign the rear suspension. 

 

Handbrake/Parking Brake/Emergency Brake/Whatever 

 

In the ROM, under “General Specification Data”, page 04-2, the handbrake is described as “Mechanical, operating on 
rear disc pads”.  Technically correct, but perhaps misleading; they operate on their own rear disc pads, not on the main 
pads operated by the footbrake. 

 

CABLE ADJUSTING:  In short, don’t.  The cable adjuster is right behind the lever under the carpet on the XJ-S 
(different location on the XJ12, which has a pull handle under the dash), but is not intended to need adjusting as the 
pads wear.  The handbrake calipers have a self-adjusting feature and should maintain proper operation of the handbrake 
throughout the life of the handbrake pads.  If the handbrake seems to need adjustment, the self-adjuster has probably 
seized.  You should address this; don’t try to get by by adjusting the cable. 

Gregory Wells of Coventry West concurs:  “The vast majority of handbrake calipers we see in our shop on inboard rear 
brake cars are seized and/or frozen up.  The things rust up badly in service and whatever grease Jag used on the 
handbrake calipers on the assembly line does a wonderful imitation of glue after a few years.  I would suggest pretty 
strongly that the handbrake calipers be inspected first before performing the cable adjustment.” 

Of course, if the calipers have been out for service or some nimnul has been fiddling with the adjustment, the cable may 
very well need adjustment.  Section 70.35.10 of the ROM stipulates that the handbrake lever should be released and the 
cable adjusted so there is some detectable slack.  This is misleading.  There are two different situations possible, and I 
shall explain how to adjust the cable under both conditions. 

If the calipers have just been serviced and reinstalled, the self-adjusters within the handbrake calipers are presumably 
adjusted fully out and a new bronze fork has been installed in each side to hold the new handbrake pads well away from 
the rotor.  With the cable not yet in place, the handbrake caliper levers will be pulled outward against their stops by the 
spring on each side.  Note their position; in fact, you might simply measure the distance between the two cable clevises. 
 Install the cable, and then adjust the cable to just pull these levers off their stops.  The tension of those two springs 
should be applied entirely on the cable, not against the stops within the calipers.  If the springs are permitted to pull the 
levers against their stops, it tends to rock the caliper and pads such that one pad rests against the rotor, which can cause 
squeaks as well as premature handbrake pad wear.  And, of course, since the caliper will adjust to compensate for that 
wear, it will continue to wear until it’s metal-to-metal. 

Adjusting the cable this tight will not cause the handbrakes to bind if they aren’t binding to begin with.  The self-
adjusters work when the travel of each lever exceeds a certain amount; it doesn’t matter if they start at their stops or a 
little off their stops.  If the levers never release past a given point, they will never adjust to be binding at that point. 

If the system is together and operating but you just read that description above and now realize that your handbrake 
cable is adjusted too loosely -- the levers are sitting against their stops when released and the cable is slack -- you’d like 
to adjust the cable tighter.  Unfortunately, presumably by now the handbrake adjusters have worked, so tightening the 
cable adjuster now may cause the pads to drag -- and this is what the instructions in the ROM are warning against. 

You have two options.  One is to take the handbrake calipers back out and reset the adjusters back to fully out and start 
over.  Presuming you don’t wanna do that, your most viable option is to adjust the cable tighter gradually, making sure 
not to cause the pads to drag. 

If the cable is really sloppy, you can take all the slop out of it right away.  As long as you’re not pulling the levers off of 
their stops, you’re not really making the handbrakes any tighter, you’re just taking slop out of the cable.  Once you have 

 
 

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the cable tightened to the point where the levers are beginning to come off their stops, then you must be careful.  
Tighten the cable adjuster only a little bit farther, and check that the wheels still turn freely.  Then leave it alone for a 
while, allowing the pads to wear a little; you might even opt to make some of your stops while driving by using the 
handbrake to help it wear a bit faster.  Try not to ever pull the handbrake handle hard enough to cause the adjusters to 
tighten up.  Then, when you can get the handle up to the first click without any noticeable drag, go back in and adjust it 
a bit tighter.  Repeat until the levers are just off their stops with the handbrake released. 

By the way, the ROM fails to mention that the way to get at that adjuster is to unbolt the seat belt from the floor on the 
driver’s side. 

 

DISCONNECTING THE HANDBRAKE CABLE:  In the Haynes manual, Chapter 9, Section 18, step 5 describes 
disconnecting the handbrake cable from a caliper operating lever by extracting a split pin and a clevis pin.  The 
arrangement they are describing is illustrated in Fig. 9.18.  Must be an XJ12 thing, because the handbrake cable on the 
XJ-S isn’t attached that way.  The ROM shows the connection correctly. 

In the ROM, Section 70.55.04, steps 1 and 2 describe peeling back the carpet near the handbrake handle and backing 
off the cable adjusting nuts.  This is totally unnecessary; just make sure the handbrake is in the completely released 
position.  If the cable is adjusted properly, it should not require loosening in order to disengage or reengage the cable at 
the levers on the brake.  It should be possible to pull the levers together enough to pop the cable off or to pop it back on. 
 Note that it will require moving both levers, however; one is operated by the cable itself and the other by the housing 
moving the opposite direction, but both movements will be needed to disengage the cable. 

Step 4 in the ROM starts with “Using suitable lever...” in describing how to disconnect the handbrake cable from the 
caliper arm.  Any sort of lever is unnecessary; the cable is easily disconnected by hand without tools.  Merely pull the 
two levers towards each other and pop the cable tip out of the block at the end of the caliper arm on the passenger’s 
side.  Then pry the little rubber boot off the end of the cable housing at the block at the end of the caliper arm on the 
driver’s side (as mentioned in step 5), and slide the cable housing back and out. 

 

HANDBRAKE LEVER DAMAGE:  As mentioned above, the cable attachments on the XJ-S don’t require the removal 
of a split pin to remove; they can be engaged and disengaged by hand, slipping the cable into each clevis through a slot 
in one side.  The author found those clevises to be damaged, though.  They get spread a little bit, which just makes the 
ends of the cable fit loosely in the holes.  But the clevis no longer pivots; it gets jammed, since it is spread wider within 
the side plates of the arm.   It actually spreads the ends of the levers themselves a little bit.  This might not be a huge 
deal, since they seem to get jammed in nearly the correct position. 

This whole situation didn’t seem cause for major concerns; there are no known reports of the thing actually coming 
apart in service.  Just the same, though, while in there, I made two changes.  First, I carefully squeezed the clevises back 
to their original shape so that they would spin freely in the lever arms.  Second, when refitting the cable, I turned the 
clevises around so that the slot faced towards the lever rather than away.  This makes cable attachment far more fiddly 
since you must feed the end through the tiny gap between the clevis and the lever before sliding it through the slot.  The 
opening is so tight that it actually wouldn’t fit; I ground three flats on the sides of the cable tip to help get it to fit 
through the levers.  Once the cable is in place, those flats have no effect.  With the clevises turned around this way, it 
seems far less likely that they will spread open because the lever itself will prevent them from spreading. 

Another option, of course, might be to convert to the other design attachment using the split pin -- but that would 
probably require buying new handbrake calipers, and that would require finding them.  Perhaps an easier fix would be 
to simply cut the weak clevises out and fabricate some replacements with more meat to them. 

 

DUMB MISTAKES WHEN CONNECTING THE HANDBRAKE CABLE:  You got the cable off, but now you can’t 
get it back on!  It turns out that if you're fiddling with the cable end underneath the car and push the cable into the 
housing a bit, it applies the handbrake!  Up at the lever inside the car, the same thing happens that would happen if you 

 
 

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pulled the lever up and set it back down: it doesn't look any different, but the handbrake is applied!  Doesn't make any 
sound, either, no clicks, nothing to tell you what you've done. 

You can go into the car, pull up the handbrake, push the button, and lower it back down, and you'll put it back into 
released position -- but it's hard to tell you've done anything until you get back under the car and find you have more 
slack!  And good luck getting the cable latched onto the ends of the levers without accidentally pushing the cable in a 
little bit again, and have to get back out from under the car and manipulate the handle again. 

 

HANDBRAKE CALIPER REMOVAL:  Both the ROM and the Haynes describe how to remove the handbrake 
calipers without dropping the rear subframe from the car.  Jan Wikström describes the work:  “It’s a fairly tinkery job, 
and definitely easier the second time... If you have a reasonable manual with a good picture of the system, patience is 
really all you need (you’ll be working by feel as you can’t see the upper side of the handbrake bits).” 

Note that the reinstallation is considerably trickier than the removal.  The pivot pins in the main caliper that the 
handbrake caliper attaches to also hold a bronze fork with tines that insert into holes in the top of each caliper half.  The 
purpose of this bronze fork is to act as a spring to pull the pads back off the disk a little bit -- but just a little bit.  As the 
handbrake pads wear and the caliper moves closer to the rotor, it pulls the bronze fork far enough to deform it -- which 
leaves it just the right shape to pull the pads back just a little bit again. 

So, to ensure proper operation, this means that prior to assembly the tines on the bronze fork should be positioned to 
hold the handbrake calipers away from the rotor a little bit.  Simultaneously, the caliper adjuster itself should be 
adjusted to hold the pads away from the rotor a little bit.  So, after the calipers are in with the fork properly installed, the 
lever on each handbrake caliper can be manually actuated a few times to allow the self-adjusters to bring the calipers 
back up near the rotor -- and properly “set” the bronze fork to be applying the correct amount of retraction.  Manually 
operating the levers also serves to confirm that both adjusters are working prior to connecting the cable. 

Several owners have reported errors in installing the pivot pins -- missing the entire inner boss on the main caliper, 
apparently.  Bob Gallivan says, “Not only will they thread in but they look to be correct while missing the lower hole 
completely.  Been there & have the crick in my neck to prove it...”  After Carlos Artal was told this might explain the 
problems he was having, he reported:  “I put the car on ramps again, and proceed to take the h/b calipers off.  Well, not 
1 or 2 of the fixing bolts were out of place, but 3 of them were, with just one poor guy left there to do all the work!” 

Another common problem is that the tines of the bronze fork end up on the disc side of the caliper -- against the disc 
side of the pad backing plate -- instead of in the holes in the caliper where they belong. 

Tip:  Use a pair of 1/4” rods about 3” long to assemble the calipers instead of the pivot pins.  This allows you to install 
the calipers with these substitute pivots first, then finagle the bronze fork into place (since there are no heads on the 
substitute pins), and finally to carefully remove the substitute pins one at a time and replace them with the actual pins.  
You can grind a tapered end on the substitute pins to make insertion easier; in fact, you could use 3/16” or 6mm rods 
just to make insertion really easy. 

If you have the main caliper out, by all means take advantage of the situation and trial-assemble the handbrake calipers 
on it before putting it in the car. 

 

HANDBRAKE PAD CHANGE:  Since the handbrake calipers on Jaguars with inboard rear brakes are separate from 
the main calipers, they also use dedicated pads.  Really, these pads should never need replacement -- what are you 
doing, using them to slow going downhill or something? 

The lining on new handbrake pads is about 7/16” thick, all the way across.  However, since the calipers pivot around 
the attachments on the main caliper, as they wear they become tapered.  This is normal, don’t panic.  If they get worn 
too far, though, the rear end of the caliper will hit the rotor.  The service limit of 1/8” on the main pads is probably a 
good number for these pads as well, but you need to be measuring the lining thickness at the thin end.