Got around to replacing my pads tonight and despite what the dealer claims I still think they are not releasing all the way which is the cause of more the excessive brake dust. So after removing the allen pins and the front holder I gently wiggled the caliper to loosen things up. Zero movement. Needed to spend about 10 minutes prying both sides off. For anyone else who has done 'em was this your experience? I have a feeling that the e brake isn't fully releasing and when my wife took it in the lazy service department simply spun the hub and called it good. My guess is that any bind was burned off in the hour drive to get there and they didn't bother to apply the e brake and do it again. When I say excessive, I washed the wheels completely on Saturday. She might have driven 50 miles since then and the entire inside of the wheels were black again with the outside maybe 1/4 completely covered. Is this strike 3 for Jaguar West Chester? Strike one was not "finding" the TSB for the faulty door locks that freeze in the winter. Strike two was at the last service not putting a load test on the battery which promply died 3 weeks later which I am sure a load test would have shown it was no longer up to the minium CCA.

 

I replaced the rear pads on both my XFS and XFR and never had a problem with getting the calipers off, on the contrary the calipers almost fell off the caliper brackets.
So it does sound like you have (or had) an e brake problem.

 

Thanks for the confirmation. Only other time I had this kind of problem were when I had a caliper seize but wanted to be sure I wasn't missing something. Guess it is time to find a new place to take the darn thing since West Chester Jaguar doesn't seem to actually want to do warranty work

 

Once you take the caliper slide bolts out, the caliper should move around quite a bit. It shouldn't be a mission or need to be pryed off.

 

That is not nessissarly true.

As pads and disc wear, the pads wear a large grove/path into the disc and that leave a ridge on both sides of the rotor that you have to slide the caliper with the pads still in the pad seats past those lips to remove the caliper.


This can be very difficult to do.

The best way is with a large screw driver or small pry bar. This will most likely damage the old pads as they get drug across the lip on the rotor, but you are going to replace them anyway.

Disc braking systems operate with the pads always in contact with the rotor. The piston in the caliper only moves very little in and out during a normal braking motion. This is why the pads get stuck on the rotor "lip". And because the Jaguar rear caliper requires a tool to not only press the piston back into the bore, but also turn into it, you cannot move the piston back into the bore even a little bit before you remove the pads completely.

Our cars use the back brakes more than the fronts. Not only to stop the car but also for the traction control system. And when normal braking, the rears are applied harder and quicker than the fronts to keep the nose of the car from diving. Most owners only get 15,000 to 20,000 miles before the rear pads need to be replaced. That causes a LOT of dust, all the time.

If your caliper pins are clean, the rubber boots are good, and the piston "screws" back into the bore, you should just have to clean, relube and reassemble with new pads/rotors you will be good to go.

If the pins are dirty or rusty, I use a wire wheel on a bench grinder and clean them and relube with caliper grease.

Good luck.

 

Yep, the explanation about the pads having to clear the lip on the edge of the rotor makes sense to me. It's just that both times I replaced the rear pads the rotors hadn't worn much and didn't have any noticeable lip.

 

I have done mine and yes you need the tool that turns them in while it compresses the pistons. Trying to force them in may damage the calipers. You can buy the tool at most places or borrow one at many nationally franchised parts stores.

 

Do the park brake reset procedure. It's in the manual. If not done when the battery or rear pads are changed the brakes can bind.

 

These cars have a sliding caliper design. They move laterally on a set of pins. A wear ridge on the outside edge of a rotor should not cause the caliper to hang up unless the pins are stuck.

 

Yes, Mikey, it will. The caliper is one solid "clamp" that holds the pads tight against the rotor. The pins only let the caliper float to center on the rotor.


Once the caliper piston tightens up the pads against the rotor, it only allows the pads to release very little. Otherwise, you would experience a long brake pedal travel to engage the brakes.


Once the rotor has worn down from many miles of use, a very noticeable lip is present on both sides of the rotor and that causes the pads to become stuck in the groove made thinner by normal braking when you attempt to remove the caliper off the rotor and caliper bracket.


Now, what you do need to look for after you remove the caliper is "are the pads and rotors worn evenly between the inboard and outboard pads and rotor surface?"


If you have a pad that has thicker material on either the leading or trailing edge of a pad or the inboard surface is thicker/thinner than the outboard pad, then you do have issues with sliding pins not allowing the caliper to float to center on the rotor or a piston not releasing properly.

 

False. The caliper must be free enough on the pins that it can easily be forced in the opposite direction moving the non-piston side pad away from the rotor. This is probably why the OP had so much trouble.

 

Stupid question, did you release the parking brake first and leave the keys in the car so it would not reset?
A large lip on the edge of the rotors always leaves me prying the damn calipers off the rotors as the edge of the pad catches it. Also are you aware of 2 facts. Light nonaggressive braking(dare i say female braking) activates the rear brakes more than the front to reduce nose dive. And this creats alot of brake dust on the rear. Volvos and others are the same.
2, if brakes drag at all this generates alot of heat quickly expanding the pads without touching the brakes and causes the rear brakes to lock up. Cars that ive had over the years with dragging rear brakes from a parking brake fault i can barely get in the shop on my lift from the parking lot before the rear pads lockup tight on the rotors. Just food for thought

 

Yup but good question. Parking brake was released and keys were in the house a 100 yards away. There is so much dust and the pads are about 1/2 in 5-6 thousand miles. There is something going on that isn't right. Even my motorcycle has 3x the brake life and those pads are thin as can be.

As for the lip, the lip doesn't come into play on this set up as the pads stay in the caliper bracket so you're not trying to pull old pads over it. Pins were just fine, no issues with sliding and all 4 pads were worn pretty much even.

 

As soon as the car sees the smart key leave the car it sets the parking brake again so that may be why you cannot get the caliper up.

 

If it does that the light doesn't come on but again this doesn't explain rear pads with a life of at best 12k or so much dust in 50 miles you can't see the wheel. I've had race cars where pads lasted longer than that. Also would explain the crappy mileage that she gets, it is only a tick or two better then our XJR gets.

 

The EPB will release with the transmission in gear with th engin running and your foot on the gas. Are you sure your EPB is releasing and applying properly? My left rear caliper EPB mechanism was seized and it ate the pads very quickly.

 

Well it went in to the West Chester Jaguar for excessive brake dust suggesting that the e brake wasn't releasing properly. My guess from their inability to even find a TSB in the past they looked at their magic 8 ball which said all was good. Gotta love warranties that you can't get anything out of. It is getting as bad as health insurance.

 

Not true. Certainly on UK cars. Maybe US are programmed differently but i doubt it.
The only time I've had problems with dragging resr brakes was when i changed the battery and forgot to do the park brake reset procedure.

 

Yep, say here with both my Oz-spec XFs, no "auto" EPB application when removing the fob from the car.

 

Well it is back at the dealer. Gave my wife a 17 or 18 diesel. Interesting car. Can't stand the blind spots from the pillars, the steering wheel looks and feels like it would be happier in a Kia Rio and the tranny and drive by wire don't seem to be happy with the engine. You can't seem to start out without it going to full throttle. It does seem to get decent mileage. Says 31.8 over its 3k of life, for a car that has likely spent its life in Philly traffic that is pretty darn good imho.