Disbalanced parking brakes

Hello all,

yesterday the big biennal event about keeping cars on the road took place for the Jag: it was checked for roadworthiness - MoT in some regions of this planet, MFK in others and TÜV in this neck of the woods.

The examiner was pretty enthousiastic about the car, the undercarriage and the suspension. The brake test bench yielded 320 vs. 310 daN front and 260 vs. 240 daN rear, but for the parking brake a devastating 60 vs. 260 daN. Two years ago the car passed with 100 vs. 190 daN at the parking brake. While a parking brake is not required to work as evenly as the operating brakes, the present difference is excessive.

Now my question - without even having looked at the system: Given that there obviously is a longer trend to disbalanced operation, is there any major suspect? Given the time it took and the fact that the rh brake is even stronger than two years ago I’d tend to assume that the lever mechanism distributing the pulling power from the main wire to the two brakes is seized. Of course, there might also be oil or grease in the brake itself - but then it should contaminate the rotor and, consequently, affect the functioning of the rear operating brake, shouldn’t it?

Any ideas welcome - I have to fix this thing after my vacation!

Thank you all


75 XJ6L 4.2 auto (UK spec)

I think you are on the right path with the equalising mechanism being compromised and probably rusted. Time to get underneath :frowning:

Could be many things, including a gummed up self adjuster.

If it were oil contamination then I’d expect the retarding force values on the normal brakes to be similarly disbalanced.

At least you have something to look forward to after your vacation.

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Most probably one of your handbrake pads is de-laminated or completely worn.
Whatever the story is, if you want to fix it, the handbrake mechanism has to come out.


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The first step is certainly to check the brake pads, Jochen - as Aristides suggests…

…then watch the movement of the operating levers’ movement as handbrake is operated. Being a Bowden arrangement the levers should move equally, but in opposite directions and basically exert equal pressures on the pads. It is a sometimes occurrence that pad material is dislodged if the car is moving with the handbrake on…

The self adjusting mechanism, if failing, would basically affect handbrake lever travel…

xj6 85 Sov Europe (UK/NZ)

There are only two fixes that I know of for the unevenness of the handbrake function and they both involve some modification.

Thanks to the one sided pull of the cable on the parallelogram mechanism, one side of the handbrake tends to come on before the other. The second side only comes into play when the free play taken up by the force acting on the first side equals the force needed to move the second side, then they move together. Sadly, so much free play is taken up getting to this point that the braking strength is very uneven.

The first (and best) fix is to let the parallelogram mechanism float. This can be done by cutting the steel rod it is mounted on with to the cage roughly half way along its length and enclosing it in a sheath (i.e. a steel tube) which is then welded to the stub of the part which attaches to the cage. This means that when the handbrake is applied, the entire mechanism is pulled forward, pulling both sides equally. Because the whole mechanism floats, any unevenness in force from side to side has to be taken up by the springs in the mechanism. Obviously you’ll need to remove the IRS to effect this fix.

The second fix which works is to alter the end fitting on the handbrake cable such that the clevis pin hole at the IRS end makes the cable end shorter. This has the effect of leveraging up the pull of the handbrake cable before the parallelogram runs out of movement and thus upping the braking power on both sides. The lack of balance still remains, in that one side only provides braking power once the other has been pulled tight, but as you don’t run out of cable to pull, it evens up once the first brake binds.

Method #1 is the most elegant. Think of it as converting a side pull brake on a bicycle into a centre pull brake, whereas #2 is effectively making a stronger side pull brake.

kind regards

Marek, are you describing the E Type arrangement? Maybe the SII XJ is different, but the last version was the cable coming in from the drivers‘ side, outer sheath connecting to the first lever, inner wire to the second.
The pads can be inspected with a mirror. 260 for a handbrake is a lot! My main brakes yielded 360, 350, 290, 280. Handbrake was assumed 120, 120 but this time it wasn’t even able to hold the car in gear. Much better just a few weeks ago. Something to attend to, hopefully next week.

Good luck, Jochen.

Yes I am and yes, the mechanism did change. The ratchet mechanism inside the levers remained the same and this also may need looking at.

kind regards

This would be the modified E Type arrangement. I agree that the pads and travel should be inspected on a lift and if unsatisfactory, so should the adjustment mechanism which means ‚irs out‘.


Hello Jochen,
As allready advised first check that there is “meat” on the pads,
To enable the self adjusters to operate the levers must return to the fully off position,
99 times out of a 100 the main cable inhibits this, so, if the pad material is OK proceed thus-
Disconnect the main cable then push the levers to the off position then place a bar to operate
the levers to the on position, repeat this off/on sequence several times on each caliper.
If your workshop is quiet you should hear the self adjusters “click” resuting in minimal
movement of the levers, If this works the main cable will require adjustementt,
Sometimes the grease used in the handbrake calipers goes hard stopping function
of the self adjusters, more work then required.
Peter B.

You are right David and the two actuating mechanisms are totally different, although the ‘pincer principle’ is the same. Thankfully, the XJ system is much simpler. I had a Series 2 Daimler XJ around the time I met Jochen and it failed MoT for exactly the same reason, even though the brake held the car on quite a steep hill.

Being a Daimler it had an LSD and I could have insisted it was not tested on normal floor rollers. By reading each wheel individually, they can give inaccurate results and damage the clutches that link the wheels together. MoT stations carry an inertia-type meter for brake testing by road test in such cases, which the car would have passed.

I had two retests before it passed and simply had to tighten and clean everything progressively until the difference was small enough to pass (it never disappeared completely). From memory I think I had to tighten the weak side so it was lightly dragging an then backed it off when I got home.

Mine might not return to fully off and I’ll back off the cable which is at the adjustment limit, then move the arms to their outer and inner limits and hope for clicking noises as I know the pads have lining. I want the brake to work when the engine runs again.
If it holds up on a steepish hill (as in the short road to the remote parking area at the Uni coming from Litzelstetten) it will definitely pass as long as it’s not one side doing all the work…
The brake test stands I know consist of to electric motors that turn the wheels at the same speed, left and right. A load sensor (like in a scale) measures the deflection due to the torque of the motor against the braking force on each side respectively. The motors keep the same speed left and right, there shouldn’t be any use of the LSD clutches.

Thank you all for the quick and detailed info!

So after two weeks of beach volley, hiking and sufficient good food and wine for compensation a lift and another person should be enough to take the first step. Then I’ll either have to refit new pads or just get the whole assembly going again.

Thanks, Marek, for the details about the upgrade, but for the moment I’d be happy to simply restore the stock functioning brakes. If I read the ROM correctly I should be set with taking off the tie plate and am not looking at a full-IRS-out scenario …

BTW, upon returning to a parking garage recently I was struck by the looks of the car and amazed again how Sir William got the lines right - even on the extended version of his design. And some graphical elements like straight lines add to to effect of the curves.

Thanks again


75 XJ6L 4.2 auto (UK spec)

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Open to be corrected here but I think you can remove the callipers by rolling them over the rotor and removing them from the rear of the cage?

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I haven’t been there or done it yet, but the ROM says to “slide caliper around brake disc and withdraw through gap exposed by removal of tie plate” (70.55.04). Now “withdraw through gap” sounds pretty much like “manouvre fridge through trunk lid opening of Austin Mini”, which makes me suspect that there isn’t really any other way of getting access easier.

But thanks! - I’m grateful for any attempt of getting through this as painless as possible and will keep eyes open where I find chances to avoid bigger problems


75 XJ6L 4.2 auto (UK spec)

It’s quite doable. I’ve done it. Not too difficult, really. You can almost whistle as you go.

Reinstalling them is where foul language is likely to arise.


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So would - provided there was a lift so the whole affair can just be rolled out or a gearbox jack - disconnecting the brake line, driveshaft, exhaust, four mounts and two metalastics be easier?
I know my exhaust would come loose and the rest doesn’t seem like a big deal to me.
Also, if needed, I could lend a hand from the 11th onwards if needed and IRS out would be needed.

IMO, since it’s only the handbrake calipers needing repair, and in consideration total time/effort involved, I would say ‘no’.


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Thanks again! That was pretty much what I hoped to hear, Doug, and thanks, David, for the kind offer, but for the moment I’d be more than happy with a small solution. I seriously hope I won’t have to get back to you …

Best wishes


75 XJ6L 4.2 auto (UK spec)

Hello everybody,

having just returned from summer vacation I’ll tackle the hand brake job tomorrow. In the meantime I’ve got new brake pads, installation kits, the “forks” (9750) and holding brackets (9751).

The first parts of the job don’t seem to be overly challenging. Detaching the hand brake cable is easy to be done as the levers protrude from the IRS cage.

The next step is trickier: the ROM invites to “turn down locking tabs” and then to “remove mounting bolts, tab washer and retraction lever”. Looking at 1J 15 R, which part is the locking tab and which part is the mounting bolt? I’d assume that the “turn down the locking tab” relates to the clips 3752 while the mounting bolts are 8845. Am I right? Then I’d guess that the lever part can be taken out and the rest of the caliper manouvered around the disk backwards and out through the bottom.

The other thing I can’t really make a picture of yet is the position and installation of the forks. It is neither clear to me where they are mounted to the handbrake calipers nor how and whether they have to come out and be replaced - I hope this becomes clear once the calipers are out and on the work bench.

Any info welcome! In particular pics with the handbrake calipers installed would be very helpful.

Best regards and thanks in advance


75 XJ6L 4.2 auto (UK spec)