Goooooood morning.

Here is a brain teaser for all the smart members out there. I hope someone can help me.

2010 Jaguar XJ 5.0 litre Super-charged. Only 87000 kms (54000 miles).

​​​​​Shudder on braking - cannot find the problem!

Work done:
1. New brake disks and new brake pads front AND back.
2. New upper control arms front.
3. New bushes/bushings on both lower front control arms.
4. New link stabilizers rear.

Any guidance appreciated...

Regards,

Tim

 

Wheel bearings ?

 

Gummed up / stuck caliper slide pins?

 

Timothy, you are not the only one suffering from this. I have essentially ruled it down to a sticking piston in what I believe to be my right front caliper. What I am believing is happening is that at slow speeds, not enough pressure is being applied to make the caliper grab, which is causing the other wheel to get the braking and put the shutter in the steering wheel. I found that if you get on the brakes harder, the steering wheel does not shutter back and forth. Just under light braking. I am going to be rebuilding both of my calipers and doing new rotors and pads here shortly.

 

When you changed the rotors: Did you clean the surface of the hub what are against the surface of the rotor? If there are dirt/rust even 0.1mm on one spot, the effect are same that you have warped disk.
I use rotary wirebush on electric drill to clean hub surface. (Allways use safety eyeprotection!!)

 

I have been having front brake shudder for years! The shudder is while braking at all speeds.
It reduces a bit when I pump the brakes at idle but still comes back. This is why I am thinking it is the rotos.

The dealer had replaced the pads and rotors twice and the shudder came back soon after.
A few months ago, I had installed after market rebuilt calipers and the shudder went away for a few months but it now came back.
The after market calipers look rusted when viewed through the wheels.
I have replaced the rotors also with after market slotted rotors - along with the calipers and brake pads. I guess I can check if there is a rotor warp but seems unlikely. If I have the car opened for checking rotors, might as well replace parts, including calipers.
Should I replace the calipers again? If so, from whom?
Hesitant to spend $500/ea on new OEM. Are there any aftermarket new calipers?
Any suggestions for a good rebuilt calipers which wont show rust?
I guess I am going to try greasing caliper pins but I dont want to have to do that every few months, do I? Do OEM calipers work better? I hope there is a good after market or rebuilt caliper - did any of you find a good source?

2013 xjl 3.0l portfolio, 100k miles

 

jaguarxjl, you sound like you are handy. Look up a company called Centrix. They sell rebuild kits for the calipers. that is what I am planning on doing with my front calipers. Yes, it will add an hour or so to the brake job, but i am going to break the front calipers all the way down, look for any signs of rubbing and then the kit replaces all the rubber/wear components. That should give some nice surfaces for stuff to float across.

Below is a rebuild kit from a company called Carlson. $25 for both calipers to rebuild.

As for the rust issue. Since you will have the calipers broken down, now is a time to put a thin layer of high temp paint on the calipers. That will stop the rust and give you a look that you may have been wanting. Worst case, you hit them with some silver paint and the calipers will look new from now on. You just don't want to go crazy with many thick coats of paint. You can start insulating the calipers and this can start to lead to brake fade if you were to go out and really start hammering on the car and doing long, hard braking over and over. Most people would never do that to their car, hence why I don't worry about it too much.

 

On a previous thread, we talked about that brake shudder in the peddle. One conclusion was not a warped rotor as I was initially thinking but a build up of the break pad compound deposited the rotors from heat and hard breaking. The advice was go to a shop that will "skim" the disk and clean it off.
As far as making pretty calipers, I just bought the MGP caliper covers in red with silver embossed logos. Can't wait to see how they look installed.

 

As i have previously posted on other sections / model of this forum their is no such thing as Warped discs /rotor , It has been proved time and time again by very knowledgeable people such as USA racing drivers and Mechanics , Discs are made of cast iron /steel . my money is on sticky caliper as Kim says as OP has new discs so no heat transfer on the discs to cause shudder

 

I dont do the repairs myself - my employee does. I dont want to leave the car unusable, while the calipers are being painted, plus it is a lot of time/work, even if for my own employee.
I did buy rebuilt Centrix calipers from Rock auto and they rusted! There was one other company claiming that they clean the calipers for other cars to make sure they wont rust but I could not find rebuilt calipers for my car, from that company.

I bought new ATE ($360) calipers but they didnt come with the bracket (14 in pic) and the caliper guide pins (12). So, another $400 for these! Rebuilt caliper sets are only $100 net, and they come fully assembled but I am concerned that they too will rust within a year!

 

Strangely, over the past few days, the brake shudder went down by 70%, all by itself. Not sure what made this happen. I did try to do some hard braking both forward and reverse but there was no immediate improvement. One day (due to weather change from 80s to 60s?), I suddenly realized that the shudder went down a lot but it is still clearly perceptible. I am still going to replace the calipers.

 

I usually try some hard braking before anything else. A good beating and then keep driving to let things cool off. Don't come to a stand still with hot disc's!
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I changed the calipers again. The rotors looked fine. The shudder continues - mostly at highway speeds. I assume the shudder is from suspension issue. Anyone fixed the brake shudder by fixing a any particular suspension component or bushings?