The left rear brake caliper is dragging causing extensive brake dust and heat. The right rear caliper also appears to be dragging, but not as severe.

I completed a four-wheel rotor and brake pad replacement 20 days ago along with brake fluid replacement and bleeding the entire system. The parking brake was released when replaceing the rear rotors and pads. Everything appeared great when completed.

Today I found a procedure for resetting the electric parking brake, which was for an XS, however it did not correct condition. It would appear that the electric parking brake is not releasing completely. Are there mechanical parts that may become corroded which inhibit the parking brake from completely releasing? Is the parking brake reset proceedure the same for an XJ.

What could be other causes for this? My next suspicion was that the caliper was needs to be rebuilt. Has anyone experienced anything similar this condition.

 

Removed rear wheels. Checked emergency brake cables which were open to stop on both calipers and cables free. Ruled out electric emergency brake.

Removed left caliper and found inside left brake pad worn on an angle and showed signs of excessive heat. The piston notch was not orientated to pin on brake pad. It was about 90 degrees off.

Right rear was not badly worn, but notch on piston alignment to inside pad pin was was slightly off.

Ruled out electric parking brake since both calipers opened to stop when emergency brake disengaged.

Retracted pistons and orientated notch, with retractor tool, to pins on a new set of pads. Reset parking brake and test drove and found left rear wheel still excessively hot. Obviously still dragging.

Whats left? The left rear caliper seemed to retract normally? Help

 

First check that all of your guide pins and sliding interfaces between the caliper and caliper mount are free, clean and lubricated with the proper lubricant. This is a must in any brake service. You must have done this before the rest of this post might be applicable.

If that does not work ...

Sometimes the piston gets sticky.

The following is not sanctioned in any text book, but it has worked in the past on stubborn cases of a sticking brake piston. Use at your own risk.

Use the old pads, or one of the new pads to keep the piston from popping out of the bore. Apply pedal pressure to move the piston *partially* out of the bore. Fully seat the piston. Repeat several times. You should be able to feel that the retraction operation is taking less effort.

The operation lets some brake fluid seep out to the piston seal for lubrication and cleans up the seal to bore interface.

 

plums, that does sound like a good procedure. Otherwise, replacing a caliper is probably pretty expensive on a Jag.

 

Well it works and pistons have been known to be trouble free for years afterwards. But every user is on his own because it is definitely not sanctioned by any auto repair text book.

Other than new calipers, self rebuilding is next best for those who can do it properly. The store bought rebuilts might be prettier, but you know the self rebuild condition better.

 

Update... removed caliper and disasssembled. All the slide pins were lubed firest time around. Took piston out of the bore, cleaned it thoruoghly and reasseembled. Really nothing obvoious found. There is an assembly in the piston that is released with a clip. Found nothing. In the bore there's another assembly which I didn't remove just cleaned it. Bleed the caliper with no improvement. Its obvoiusly dragging. Biizzare! It must be the assembly in the bore, which appeares to be part of the parking brake. I looked up rebuild kits for $52.00 that is basically looks like the boot seal. Unless there is something else it looks like a new caliper. I need help from the brain trust. I'm just a simple fireman. I've spent less time treating a heart attack, back in the day.

 

JTIS time if you are dealing with a parking brake mechanism that needs to be released when pushing back the piston.

 

Parking brake released fine. Piston retraacted fine with tool, Re-bled caliperand still not releasing. Ordered replacement.

 

I have done many brake jobs over the years, but are the rears on this a complicated pain to do?

 

Ordered rebuilt caliper, I installed it and re-bled the entire system and reset the emergency brake system. It was obvious when I installed the new unit that there was something binding the emergency brake lever on the back of the old caliper. Brakes are now better than new.

Replacement of brakes and rotors on the XJ is easy, if you have the tools and the instructions unique to the Jaguars. While this took longer than I would have preferred the results were great. I will post the entire procedure with PDF's to save someone else a lot of time.

 

Thanks for the feedback , good to read you fixed the problem

 

Bless you Ed,

So many of our thread starters just take the info and run and we never find out how things turned out.
Kudos to those like yourself who share with us what worked and what didn't.

 

+1