Hey guys,
I have an 04 XJ8. I just recently replaced the rotors and pads on the car all the way around. I used centric rotors all around and rear pads while using akenebono pads on the front of the car. I removed the calipers from the car to paint them and at that time drained the entire system of brake fluid. I refilled the car with Valvoline or Castrol universal dot 3/4.

I used to have 22's on the car before the brake job and other than a little bit of a rough ride, the car was vibration and shimmy free.

I noticed after the brake job, the car seems to shimmy/vibrate at all speeds to some degree. Its not all that noticeable at 50 mph but pretty noticeable at 70 while disappearing a little at 80.

I thought it might be that the 22's front tires where starting to split so I replaced them with the xk8 setena wheels and new tires from the ebay seller. Both the wheels and tires are brand new. I had my local indy tire guy road force all the new stuff before installing on the car (I looked at the print out, and they are balanced perfectly). The car still has the same shimmys and vibrations as when the 22's where on there after the brake job.

Can any one help me find a solution for this problem? Has this happened to any of you? Please help! I just want my car to be smooth again.

 

I'm not clear. Is the shimmy occurring when you hit the brakes or general driving?

 

Is the Shimmy only during braking or does it shimmy while cruising too?
Did you check the rear tires?
You need to check for any damage to the wheel and tire for all 4.
Check the mounting surface of the wheels to the rotors. Make sure it all sits flush.
Since you are using aftermarket wheels I assume, make sure you are using the correct lug nuts for those wheels and that wheel hubs fit the hub on the car. Aftermarket wheels will ofter have a ring to make sure the wheel is centered on the hub.
If you shimmy is only during braking then you need to have you brand new rotors resurfaced. This is comon when ordering new rotors. They don't always come perfect. I seen this many times. Just cause its a new rotor doesn't mean it was cut perfectly true.
You can also try rotating your tires around and see if the shimmy changes. Then you might me able to diagnose it better

 

Actually the car does not shimmy or vibrate while braking. It only occurs while crusing. Under 50 ehhh you can tell but just barely. 60 seemed to be the worst speed while fading the faster I go but it is still noticeable at 80. The wheels and tires are brand new. They where just shipped here. We inspected every wheel and tire before they where mounted and road forced to perfection. So I dont think this is a wheel or tire problem. Like I said this vibration through the steering wheel, and the chairs and shimmying all occurred right after the brake job.

Was I not supposed to let the whole brake system drain and be empty? Is the valvoline universal dot 3/4 that I used ok and would that have any effect?

 

Unless you have a badly out of balance rotor (virtually unheard of) the problem is not with the braking system or the work you did on it. It's something to do with the wheels and tires.

BTW- you should not drain all the old fluid out and leave the system empty. Pushing the old fluid out by adding new fluid to the reservoir is the usual way of doing it.

 

Not sure if it will help but it is worth reviewing.

tsb-TireBalance-12803.pdf

 

Since you have had the tires RF balanced - my vote goes to 1 or more crooked or out of round wheels. Less likely but a possibility is a crooked tread on the tires.

I doubt the brakes are an issue (as others have pointed out) because the shimmy is present during cruse.

Shame on your tire tech/provider. They can check for a bad wheel if they know how. If you have a satisfaction guarantee, now is the time to exercise it on both the wheels and tires. It's not that you can't sort it all out. The issue is how much time and money you want to put into it.

 

I think some are getting a little off base on this one. If you noticed the vibration after the brake job and before, as well as after, you changed the tires and wheels I would lean towards something in what you took off of the car during the brake job that was not reinstalled correctly. It may not be in the actual movement of the brake pad under braking. Thus the reason you do not notice under braking. I would focus on the rotor installation itself and look at anything else you touched during the brake job.

 

Like I said in the opening post, the car with the old wheels before the brake job had no shimmy or vibration. Right after the brake job was done (by me and my first time), the vibration/shimmy was present. Then I ordered the new wheels and tires and had them installed after they where road forced. This leads me to think I did something incorrect on the brake job. Maybe the rotors where installed incorrectly? I had the calipers off the car so when I put the caliper mounting bracket I then slid the rotor on ( is anything supposed to hold the rotor on?) then slid the caliper over the rotor.

Remember, there is no shimmy when stopping, only when cruising. Any suggestions on what I might have done wrong during the brake job?

 

I did not read this part correctly earlier. Maybe find a shop that can balance them after they are mounted on the car so that the rotors are included in the spin.

I am curious about the manufacturer of the parts you used. Who makes them? Wondering about the quality of the balance on the rotors themselves.

 

Rotate the fronts to back and vice-versa. Or maybe put the old wheels back on and take a drive.

 

check the runout on all the rotors with a dial gauge.

 

From the sound of it, you have a rotor or rotors out of balance. Centric are the cheap end of the rotor spectrum, if there are going to be problems, it usually is at the inexpensive parts end.

 

No one has mentioned the lug nut torque.... That can have an effect on the rotors too.

Tom

 

Some work is especially not recommended as DIY/shadetree work despite common writeups posted here and elsewhere that "anyone can do it". I can think of at least a half dozen typical errors/mistakes DIYers often make when home brewing their own drake jobs that would lead to vibration and or shimmeys. Rather than trying to reverse analyze what might have been missed, this car should be examined by a competent tech....before someone gets hurt.

 

Amen to Steve11's post.

Hopefully you can find a brake tech who can diagnose the brake job without throwing out all your new components and starting over.

 

Well, now I have a similar problem. I just installed new tires and new rotors and slightly used pads.

The car drove perfectly before on Michelin Pilot Sport A/S Plus tires I have always sworn by, but I did not feel like spending almost $2000 this time around and took advantage of a good deal at Tire Kingdom on some Pirelli P-Zero Nero 98W 19 inch tires Tire Rack rated as a top grade tire. Needless to say, the tire company did a crappy job of balancing making the car almost undrivable and so I took it to the Jag dealer for road force balancing. The balancing eliminated 99% of the vibration and wobble in the steering at any speed, but it is not perfect. The tech made 2 observations, he said the tires all had flat spots and the rims were slightly out of round. Is it normal for Jaguar rims to not be perfectly round, I have never encountered this before?

The other part of the issue is when braking. If I brake with light to medium peddle pressure, the steering wobbles, mostly at city speeds, if I brake hard, no wobble, In either case I feel nothing unusual in the peddle.

Thoughts? I miss my smooth ride and perfect braking!!!

 

Check the run out on those new rotors. It's not uncommon for new rotors to be bad out of the box. I always check for run out on new rotors and don't allow them to turn them down if they are out of spec.
Bent wheels can be fixed reletively cheeply by a mobile service in Tampa.

 

@jahummer, I would check all the rest of your suspension to make sure no other parts are worn or lose as this can also cause a slight shimmy during braking. Also carefully inspect all brake components for slight worn parts. If the pads are too lose, it might also create a vibration.

 

As for the original problem, Is there any update? Has the problem been corrected yet?

An quick check for the rotors would be to jack up the car so the wheels are off the ground and slowly turn the wheels by hand and try to feel if there are high and low spots on the rotor. If they're really bad, the wheel will have uneven drag as you turn it.

This is not a deffinative test for the rotors, but a quick easy check that might point you in the right direction.