This is the 4 set of front disks and pads on my XJ. They last for about 3-4 month and then bend ( vibration on the wheel when braking ). Did anyone experience the same problem? How to fix it? I tried different brands including Brembo to no avail.

 

See this thread from the XK/XKR (X150) Forum.
https://www.jaguarforums.com/forum/x...raking-209622/

Rotors don't warp; they accumulate residue from rust and brake pads that builds high spots that cause the brake pedal to pulsate or shudder that's particularly noticeable during slow stops. Before having the rotors replaced or resurfaced, try the Italian brake job: on a clear highway, accelerate to 70 mph and then hit the brakes hard and slow down to around 30mph. Accelerate and repeat the process 5 or 6 times or more. That might get the rotors hot enough for the calipers and pads to remove the accumulated high spots and eliminate the shudder.

 

Another possibility is a caliper with a sticking piston. This can cause a lot of vibration. I've experienced this myself.

How many pistons do the X351 front calipers have?

How would you describe your braking technique?

 

I think they have 3 pistons, but I might be mistaken.
I am a patient driver. I rarely turn the engine to 3-4k rpm or hard brake it.

 

Thanks a lot for your help, I will try it today.

 

3 pistons is impossible. They are either 1,2, or 4. Maybe 6 or 8 is possible, but never heard of it.

 

As Stuart has said , No such thing as Warped discs (rotors ) That is a poor excuse from a poor mechanic

 

Jaguar 6-piston front caliper on my 2009 XKR.

 

I have a 2013 XJL 3.0 v6. 80,000 miles

Over the past 2 years, I have had steering vibration both at low speed braking and much more at 70 mph.
1. I had an independent mechanic replace front brakes and rotors. He said he used only original Jaguar parts. The vibration came back within a few months.
2. I sent it to the dealer and had them replace the rotors and pads. 8 months later, vibration was bad enough that I sent it back to the dealer. They replaced the rotors (and pads? I dont recall) under warranty.
3. 1 year later, the vibration has gotten very bad.
a. If this were the calipers not moving, I assume the vibration would have persisted on new rotor/pads (which it did not).
b. I am guessing that Jaguar is not buying their rotors from India or China..

Would I be correct in assuming that this is a rotor issue? I have a mechanic who can replace the rotors.

Question.
q1. would I need to replace pads also when I replace rotors?
q2. where is a good aftermarket place for buying rotors? Clearly, OEM seem no good. I had good experience from http://www.placeforbrakes.com/ with pads/rotors for my Lexus Ls600Hl

Thank you.

 

If you have continous problem with warping rotors, it might be that the surfaces on hubs, where rotors are against, are not straight or there are dirt / rust on the surface.
Hub warping can be caused exsample wrong method or too tight wheel nuts.

 

seems like a good point. Thanks. What do I do? Change the Hub?
I would have liked to think that the dealer would have cleaned the rust off the hubs..

 

Why don't you try having the rotors turned by a machine shop? That has been SOP when doing a brake pad replacement. I have always heard that the brake rotors do warp (side to side run out) from the heat cycles of use. Also they develop wear patterns that need to be machined out. You could check the rotors while they are mounted with a dial gauge.

 

For various reasons, that is not a option for me.

 

Hi,
It depends the dealer / mechanic working on the car. Some want to do it quick and ignore surface cleaning, some just simply don´t have a clue.
I use hand drill with wire brush for the lose dirt / rust and then flathead screw driver until all above surface level things are away.
By been lot of in racing last 15 years i have also seen that if your brake caliber slide pins sticks time to time, the rotor heats up more on other side than other. On cooled rotor, where air ducts in middle makes rotor to be two sides, one side expands more by heat than other. This can also make rotor warping. It is good practice time to time push pedal very hard when standing on traffic lights, to keep parts moving.
Brake pads should be fit in their braket, but stii be able to move by hand. If one side is sticking and drags, again one side of rotor gets hot.
However: I would newer get rotors to be machined straight. This can leave uneven material thikness what can cause even more problems when rotors get hot. (0.1mm (0.0039370in) don´t sound much, but when that thin layer are taken away from 1/4 of rotor surface, it start matter)

You can remove your wheel, then caliber by it´s slide pins (9mm allen key front, 7mm rear) and take rotors out and replace them again. Before install new, clean hub surface and also clean and grease caliber slide pins and clean brakepad steel guides and also under the guides by remowing them.
There are youtube videos and Repair & Service manual on Sticky section on this XJ Forum. Brake job is not master level job, but need focus and carefull mind.
Or, go to your garage and explain that your car have un-normal habit to warp disks and you want to pay bit extra that they do the job by "long way method" descripted above, not just quick swap, because that have now ended numerous unnessesary rotor changes.
Normally rotors are good up to their mimum thickess.

 

I like using a dial indicator on both the hub and rotor to determine if both are true (no runout). Harbor freight sells a clamping one for $35.

Another thought is that my braking felt significantly smoother after I fixed a bent rim. So you may want to check that your rims/ wheels are balanced/ straight.

All the best.

 

It is possible that the lugnuts are not being tightened evenly. This will cause a stress to build up in the rotor that after some heat cycles will cause the rotor to go out of true, resulting in a wobble when braking. I would also take a wire brush to the area on the hub to ensure that all chunks, rust, etc are removed so the rotor has a smooth surface to sit on. May even be of interest to run a straight edge over the hub to see if there is a high spot as you seem to have had this since the car was new. Do you know if it is always the same wheel that goes out of true? If so, may be worth a little bit of money to have a new hub put in to see if that corrects your problem.

 

Before I'd get wrapped up in changing rotors, I'd "clean off" the existing rotors by going out and doing 3-4 hard stops, 50 to 30, then drive directly home, SLOWLY rolling into your driveway, and as the car comes to a slow stop, ON IT'S OWN, without touching the brakes, place the shifter in "park", then walk away, and let the brakes THOROUGHLY cool....

 

A more detailed explanation than my Post #2.

 

I had significant runout on one of my rotors. It was measured by dial indicator to be an average of ~4.5 thousandths if I remember correctly. I believe the service manual lists 0.003 as the limit under spec. It happened about 6 months after I installed a new rotor. I got a new one sent to me under warranty and have had no problem since.

When I installed the new one I noticed that trying the rotor in different positions (ie testing each hole of the rotor on each stud) changed the runout a little (I think ~2 thousandths). I saw that trick on YouTube. So this may have helped with the new rotor.

All the best.

 

I had the same problem with my 2012 XJ 5.0 Sc, 56.000 km, vibrating while braking, very annoying.
I had the front discs resurfaced and the vibration was gone for about 25-30%.
While the mechanic was resurfacing, he already told me he thought this was not the problem because the correction was very little.
They also looked very new.

Two weeks later I went back for the rear discs and they needed a lot more correction. They were older also.
That was begin august, no problems anymore whatsoever. A happy driver now.