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Discussion Starter · #1 ·
I have the dreaded brake judder on the XJR. the discs are only 1 year old and its only done a few thousand miles on them but now I am getting a lot of vibration. Also a slight and occasional squeak at low speeds. So it looks like I will be taking the brakes apart to check everything out very soon :( .
The list of jobs is growing so I feel a bit of pulling it apart is needed after 18 months of not a lot of maintenance since getting it on the road. so a Christmas holiday job along with the rear bumper off and digging into the engine to find the dreaded start up fault codes that once cleared don't come back until I start it again.
 

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I have it slightly on my current car, and had it on previous X350. It seems an intractable fault on these cars. I notice it a lot less now I'm on 235/55 R 17 tyres. I downsized from 19" about a month ago. However why this seems to reduce the severity of the judder, I don't know ! Current problem is not enough heater output now winter is here !
 

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I had this brake judder problem develop on my S type, it only evidenced itself at 50+ Mph..
I didn't believe my discs were at fault as I had changed them out less than a year earlier.
I bought a dial gauge set and checked both front discs very carefully......no problem.

After reading lots of suggestions from this forum decided to replace the caliper pistons. Not too bad a job, just have to be careful not to nip the rubber seals when re-assembling.

Judder free now.

Good luck..............................IP
 

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Yes, my thoughts were along those lines too. Either the caliper piston sticks or the whole caliper is reluctant to slide on its locating pins.
 

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My issues, well documented in my main thread were the same

I had everything checked and brakes replaced numerous times, turned out to b a sticky caliper on one side ( passenger I think it was for me )
I had the pistons replaced along with new seals etc etc and the problem was erased, thankfully

Jim
 

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I had already done a thorough strip, clean and grease of my calipers, sliders etc. and like you was really disappointed when there was no improvement.

When I got caliper refurb. kits and stripped my old ones down I thought I had wasted my money. The original pistons and seals looked good. I went ahead and replaced them anyway. That did the trick!

Result!..................................IP
 

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Discussion Starter · #8 ·
Mine has the Brembo calipers so no sticky slider pins but with 8 pistons I think a rebuild will be done anyway on all 4 calipers.
 

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There is a website that you can buy all new pistons and seals. I just bought all new seals and when I popped the pistons they were in pretty good shape. I can't for the life of me remember the website though.
 

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I've found just the same - and even with re-setting them using the DTI, the vibration still comes back eventually. Incidentally, there was a Jaguar service bulletin on the subject.

I'm currently changing the front discs every 6 months or so, which I'm not overly worried at
 

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I had already done a thorough strip, clean and grease of my calipers, sliders etc. and like you was really disappointed when there was no improvement.

When I got caliper refurb. kits and stripped my old ones down I thought I had wasted my money. The original pistons and seals looked good. I went ahead and replaced them anyway. That did the trick!

Result!..................................IP
Could have been some dirt between the disc and hub which fell out, or just the hub not seating properly.
Having gone through a lot of investigating when I had my judder on braking problem, I never could understand the logic of a sticking calliper causing brake judder. Can you explain IP?
 

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The sticking caliper means that the pads have not fully retracted away from the disc and the pads are rubbing causing friction and heat. It is the prolonged heating that warps the disc eventually .
 

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Could have been some dirt between the disc and hub which fell out, or just the hub not seating properly.
Having gone through a lot of investigating when I had my judder on braking problem, I never could understand the logic of a sticking calliper causing brake judder. Can you explain IP?
Sorry I can't..........................All I can say is that even though the discs and calipers were given a thorough clean with particular attention being paid to mating surfaces etc. It was only when the old pistons (these looked perfect) and new pistons were installed did the problem go away.

I removed the calipers from the vehicle completely and re furbished them on the bench. The slight lip on the discs was filed off, the surfaces of the discs were given a good rub with sandpaper (not emery) on a flat surface. I replaced all and re-checked disc runout.

Thankfully this did the trick. You could try just doing a full strip and clean. The piston kits are no too expensive and come complete new seals, and the correct greases.

Good luck with yours............................IP
 

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Can you recommend the best place to buy the piston and seal referb kits from please?
In direct answer to the question, A brake refurb parts stockist.

As an interpretation of the question try Ebay, Motor factors or somewhere like http://biggred.co.uk/
 

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I had the exact same problem on my XJR with Brembo brakes, never resolved it, I ended up replacing the entire brake system for an updated custom setup
 

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