Hi All,

I have the big Alcon brakes on my 2008 XKR Coupe. Recently it has developed a steering wheel shake that my mechanic doesn't think is coming from the brakes being warped but the front lower forward control arms bushings going bad.

My car only has 6k miles.. but I do get rubber degrades over time. Has anyone else experienced this?

Thanks!!

 

My brakes shook a little bit when I first got it (72K miles) but after I used them for a bit, that went away. I think I had some debris or rust specs on the rotors. An 08 with 6k... does it sit for long periods? Could be rust spots.

 

You should have the disks resurfaced a very slight amount, and maybe scuff the pads also. Me, I had this and replaced rotors and pads. The shake went away totally. Now the rears are starting to do it also, but those are all old parts and I already purchased new rotors for that end also, no pads yet though.

 

Crumbs you defo arent driving your car enough!

Some questions:

1) Has it had an annual service regardless of mileage.
2) Is it sitting on original tyres
3) Does it have 12yr old brakes and discs/rotors fitted?
4) Have you checked your bushes?
5) Is your mechanic any good?

 

Rotors don't warp that is an excuse that a poor mechanic will use . Hot spots can build up on the rotor it is this that causes the shaking

 

Has your mechanic actually got under the car and put a crowbar/pry bar on the bushes? If so, I'd consider taking their advice, but I'd also get them to put a dial gauge on the brake disks/rotors to see if they are warped or not.
It should be a simple process of elimination, and might even show you have two problems at the same time as either problem could cause the other.
Good luck

 

Some mechanics will tell you that your rotors are warped and need to be replaced. Although extreme heat can cause a rotor to warp, in most cases vibration is more likely to be caused by an uneven build-up of brake pad material on the rotor. That causes the pad and caliper to move up and down as they grip the uneven disk surface, which you feel in the steering wheel as vibration, shimmy, or judder.

I suggest that you have your rotors checked for build-up and run-out (wobble in and out while spinning) and determine if they need to be resurfaced. Even if your rotors have sufficient thickness remaining to be machined (also called "turned"), my experience is that you're better off to buy brand new rotors, as resurfacing leaves them thinner and less effective.

I don't understand why some people buy cheap aftermarket brake pads and rotors. There's a reason why they're cheap. Brakes are critical to safety, so don't skimp out and risk your life and the lives of others. Top quality aftermarket brakes are usually OK, but I trust Jaguar engineers and prefer using OEM brake parts.

 

With 6k miles I suspect the brakes have never even been warmed up.

 

Exactly! Would you wear a Motley Crue t-shirt with your tux?

 

If discs are warped or whatever, it can usually be verified by jacking up the wheel and turning by hand while a friend gently presses the brake.
And yes, if the mechanic says it's a bushing, show be with a crow bar that it moves more than the other.

The rest of this post is not relevant for this problem, but I'll still mention it, to show how far some mechanics will go to get your $:
I had bought a new car, not Jag, and it had a special 3 year warranty, but had to serviced every 6 months to live up to that. Found a local shop that said they specialized in this type of car. Second time I picked it up from service, with only about 10k miles on it, the mechanic showed me some "high performance" discs that I would soon need. Why would I need them, car was fine and discs totally straight still. Some months later I bought new wheels and wanted to put them on. I noticed that on the front wheels, 2 wheel nuts were very very tight, and 3 were almost not tightened. In the same pattern on both wheels. How do you warp a disc? Uneven wheel nut torque...
My firm conclusion was and is that he had done that on purpose to warp my discs and sell me "better" discs at next visit. He tried to cheat me, and if unlucky, he could have caused a crash, making my brakes not working properly, or a wheel come off, break a wheel bolt.
I never visited his shop again.
Not as serious, but he also charged me 4 hours work even though there were only 2½ hours from when I delivered the car to when I picked up. When I called and asked about that, he said there had been two guys on it all the time... I'm sure the service was just to change the oil and mess with wheel nuts.

 

Appalling!
I always check the wheel torque a few miles after a service (including my own work) where the wheels are off. 1) I want to ensure I can loosen the lug nuts off for a flat tire and 2) verify the proper torque.

 

Try a few hard 60-0 braking routines and see if that makes a difference.

 

No self-respecting guy who wears a Motley Crue t-shirt would own a tux!

 

Amen to that.

 

My local Jaguar indy is very adamant on using Jaguar OEM parts especially on the braking system. He said he's seen it too many times where the aftermarket brakes just end up costing their customers in the long run. They've been a Jaguar specialist 30+ years.

 

Check your control arms and ball joints. Worn suspension has free play that shows up as shaking or wobbling when braking.

 

I had this problem with a previous jaguar sedan with relatively new brakes, the mechanic wanted to turn the rotors which is not recommended. I tried heating them up by breaking while still accelerating. After doing it a couple times the problem went away and did not come back. I don't think anything was warped but more likely what someone suggested that it was material build up on the rotors and my action must have removed it.

 

I am fussy too about parts where safety is concerned - steering, brakes etc. Aftermarket parts can be a good solution sometimes though, provided they are reputable. TBH my XKR isn't costing me much in maintenance so OEM parts are my first port of call. Just drove 2,000 mile round trip from England tp South of France and back, for vacation. Perfect car for it!

 

Looks like nobody is actually reading your post since they are accusing your mechanic of misdiagnosing warped rotors when you specifically wrote that he says it is NOT the rotors but actually the control arm bushings. I have found this (and any alignment issues) can cause the pulsation. Follow his recommendation and do the bushings if needed and get an alignment...issue should be solved.

 

yes, this ^