I was also tracking down a similar vibration on my XK8 and had been down the bushes/shocks/changing wheels/tyres route with limited success. On the advice of another XK8 owner in the UK I went to a shop who do on-car balancing and that almost totally eliminated the problem.

The technician there said that XK8/XKRs were the commonest car they got through the doors, and they are one of very, very few places left in the UK who do on-car balancing. Both sides (front) were about 10-15g out, and the technician reckoned it was probably the brake discs. Interestingly, the discs had been replaced by the PO shortly before I bought the car.

So for definite, wheel wobble can be due to unbalanced rotating mass in the front hub assemblies, and the most likely culprit would be the discs....and this is a car with regular brakes, not the huge Brembo discs.

I've just switched to an XKR with Brembos and if/when the discs need changing I will be getting them balanced first.

 

HUNTER Checking Drum or Rotor Balance

 

Wanted to give an update: King Balancing fixed my rotors and my problem, and they painted the rotor hubs again for me (I didn't request it, they just did it).

 

Interesting. I have had wheel wobble at around 70 mph ever since I bought my car 2 1/2 years ago. Despite trying everything I could think of (wheel balancing, new bushes, wheel bearing, etc.), the problem is still there. The rotors were pretty rusty when I got the car (I have cleaned them up since), so maybe I need to get them checked.

 

My Land Rover does the same thing! Can't seem to resolve the issue no matter what.. until now. Thanks, Kev

 

I just got my 2000 XK8 with 52700 on the odometer. I drove it home last night and mine shakes around 70 also. Feels worse during acceleration and a little better coasting. Seams to be coming from the rear or drive train. I also noticed that when I hit expansion joints and bumps my front end bangs on the bump and has a short duration wobble. any Ideas? David.

 

Noise in the front over bumps, commonly sway bar bushings, search the forum, lots of info, fairly easy to replace. However, check all rubber in suspension, as it deteriorates not only with mileage but also with age. Upper wishbone bushings, upper shock mounts, lower shock bushings, are all common. As far as your vibration on the highway, also a lot of info on the forum. I would start with a good inspection of the tires, then if ok try a Hunter Road Force Balance. Again, search the forum for Hunter road force. These cars are sensitive to balance issues. In my opinion, last resort would be an out of balance rotor. I had new tires and several road force balances done to correct vibration, none really helped. Put new rotors on and had them balance checked first, they were all ok...with new rotors my vibration was better but not gone. Did another road force at a different garage, all smooth now. My vibration was caused by rotors out of balance and bad road force machine. I went back to the original garage and complained about their road force machine and they said they had other complaints so Hunter came out and had to replace the "transmission" on their machine, it was either worn or defective I guess. They gave me store credit for what I paid at the other garage.

 

I've recently changed my rotors and pads. Put about 2K miles since then. Everything was great until about a few weeks ago, when I started noticing vibration in the steering column when slowing down from high speed. Slowing down from 50 mph is smooth. The car drives extremely smooth even at 100+ mph. No shakes, no vibrations - just pure enjoyment. Slowing it down is another story. Could it be the new rotors? They're not Brembos. Any ideas or suggestions?

 

A 2005 XKR without Brembo brakes - unusual.

If it's driving smoothly then it's not suspension or steering. Vibration on braking could be:

1. uneven wear on pads
2. excessive disc run out
3. sticking caliper piston(s)

In the absence of any mechanical issues like the above, a fluid flush often dramatically improves braking quality.

Graham

 

Clarification - original equipment is Brembo. When I changed the pads (2K miles ago), I changed the front rotors as well. The rotors are not Brembo - that's what I meant.
[URL="https://www.jaguarforums.com/forum/attachments/north-east-us-me-nh-vt-ma-ri-ct-nj-ny-pa-35/40249d1366428815-jagpro-bellmore-long-island-photo-2-jpg"]

 

Also check your discs for corroded spots. I had mine standing around for a long time, just after putting new discs on. The pads then caused some corrosion spots on the discs, which caused heavy vibrations when braking from high speeds (70-100mph). Braking in city traffic felt pretty normal.

To fix it, find a place with a ProCut on-car lathe, or get new discs. I tried braking like a race driver on drugs, but the corrosion didn't come off. In fact, it can cause discs to become even more warped.

 

So you have OE Brembo Calipers. A flush could improve the brakes as the bleeding technique is slightly different from standard with the twin bleed screw Calipers and a little more difficult to expel any air.

1. fill fluid reservoir to the 'MAX' (maximum) mark.

2. prepare the left-hand front, brake-caliper for bleeding.
Connect bleed pipes and fluid containers to bleed nipples.



3. bleed the brake.
Apply pressure to brake pedal.
Open caliper's outer bleed nipple.
Fully depress brake pedal.
Close bleed nipple.
Release brake pedal.
Wait two seconds to allow system to prime.Repeat procedure until air-free brake fluid is expelled from the bleed nipple.
Repeat procedure to caliper's inner bleed nipple.

3. tighten bleed nipples to 12-16 Nm.

4. following the procedure above, bleed the brakes in the order shown:
Left-Hand Front
Right-Hand Front
Left- Hand Rear
Right-Hand Rear

I've never been convinced the order the brakes are bled makes any difference but this is the order given in JTIS.

The URL in your post #30 isn't linking so I've added the pic here.



Graham

 

Steve, thank you. David

 

Thank you Graham for taking your time to educate me on the brake bleeding process. Although there's no way that I am going to tinker with it with my two left hands , I will take the car to the dealer, so that it can be done properly. But it is definitely a good idea to be familiar with the process. I did speak to a mechanic about the issue at hand, who explained to me that the vibrations are most likely due to warped rotors. Being that the rotors have less than 2K miles on them, I believe that they should still be covered by the warranty and eligible for an exchange, since drilled rotors, according to the same mechanic may not be "cut".

 

An old proverbial goes - If it ain't broke, don't fix it. Or something to that effect. The service records on my XKR suggest that the car needs break bleed and brake fluid replacement. Since I am not a DYI when it comes to tinkering with cars, I decided to take my Jag to an authorized Jaguar dealer. Today was my appointment at Heritage Jaguar of Freeport (NY). I was told that the process is a one to one and a half hour procedure, so I decided to wait around and look at some new Jags, including the new jet black F-Type that appeals to me, oh, so greatly.
After the service was performed, the bill was paid and my car parked for me - to be picked up at the front yard, I got in and started the ignition. Before placing the J-Gate lever into drive, I gently pressed my right foot on the shiny aluminum break pedal, only to alarmingly finding it sunken all the way to the floor - OY VEY!
Back to the front desk I went, barely holding my contempt. The service man (Bill) verified my observation, then drove the car back to the shop and up on the lift it went again.

After 15 minutes Bill calls me inside the shop and says that he really does not want me to leave the dealership in the condition that the car is currently in, as if I would be suicidal enough to take that chance without him telling me that. He then proceeds to tell me that he is going to give me a rental car (free) and he wants to have his "team" inspect the car to see why the "one half (whatever that means) of the master break cylinder is not working". At this point I am concerned, because I brought the car to him in perfectly working condition, needing preventive service only.
Leaving the car at the dealership, on my way to my office, I was pondering on why many mechanics oppose the idea that changing fluids (break, steering, transmission oil, supercharger oil, etc) is a bad idea. The mechanic who recommended me not to change the break fluid, gave me an example of late model BMWs, saying that if Bimmers require transmission work, the drained oil gets saved, only to be reintroduced back into the system upon the completion of service. As a matter of fact (his "fact", not mine), only antifreeze needs to be changed every 3 years. He also said that the engine oil should be changed every 3000 miles on regular oil and 5000 miles on synthetic.
In the end of the day, one's opinion is nothing but an opinion and could be looked upon from different perspective(s). At this point I am wondering if I should have left things as they were and use the car until something would eventually break, rather than voluntarily expediting that process. I am awaiting for the call from Bill - let's see what happens.

 

While off topic to the thread in general: All that happened here is incompetence on the part of the "mechanic" that flushed your fluid. It is totally their fault, as a properly done flush will not do anything that will damage your brake system. I have flushed brake systems several times and it really isn't hard, just don't let the Master run out of fluid and it is quite simple.. If you don't keep the Master full of new fluid as you are flushing it, you will get exactly the problem that happened to you. Just because someone has "Jaguar Mechanic" written on their pajama's doesn't mean they actually know how to work on cars.

 

I won't go into a long tirade here except to say that your mechanic is under recommending the fluid changes and over recommending the oil change interval. Current wisdom on oil changes are more like 5/10K regular/synthetic though there has been significant debate on this forum about that.

You can drive a car without changing any fluids, but it is going to be very hard on the vehicle. Regular service of automotive fluids removes contaminants from the system and renews the active chemicals that allow the product to do its job.
Vector

 

Heritage Jaguar stood behind their work and, without fuss, fixed the issue, which turned out to be a non-issue after all.
It turned out that it has been a while since their mechanic has done any work on an XKR100 model. He bled the brake lines 3 times and finally got all of the air out of the system. What surprises me the most, however, is that the bothersome steering wheel column vibration is gone and the my car stops on the dime - vibration and drama free - amazing.
Graham is right, when he said that after replacement of brake fluid, the braking improves for some. It did for me.
Iam still puzzled though as to why the vibration went away. No work has been done to the pads or rotors and yet, it feels as if the Jag got an upgrade for both - solid stopping power from fluid change. Perhaps someone may offer an explanation for this.

 

Simple, the old fluid was either bad enough, or there was a small air bubble in the line such that one of the calipers never fully released, causing the vibration.

 

Calipers 'release' due to the square-cut seal inside them. As pressure forces the piston out the seal slightly twists as the piston 'drags' through it. When the pressure drops the seal relaxes to it's normal position thereby slightly retracting the piston.

You were lucky, sometimes when brakes are bled by depressing the pedal the master cylinder pistons are forced through a range of travel greater than they normally would be. This can sometimes force the piston seals to travel over accumulated detritus in the master cylinder bore and damage the seals causing an inability of the master to build pressure. The only cure for that scenario is rebuilding or replacing the master cylinder. Obviously the mechanic allowed the master to run dry while bleeding and introduced air into the system which he hadn't fully expelled before returning it to you. He should have caught that and never returned the car to you in that condition.

In regard to the vibration, quite possibly the wheels, having been removed, were returned to different positions and/or the nuts torqued properly...