ok, I'm beyond myself. Short of bug nuts.

I've replaced just about everything but the steering rack in the front of my '04 XJR. And I still have this rattle in the front suspension. I've replaced the lower control arms, the upper control arms, the sway bar end links, the transmission support mount and the shocks. The hubs check out as do the sway bar bushings. WTF!!!

I just measured the hub to fender, and I'm coming up with (16 inches) 406mm in the front and (15.5 inches) 394mm in the rear. Could this be causing a rattle? I think that's about 25mm above spec all the way around.

I'm tempted to drain the air suspension and drain the battery and let everything reset, but I have a feeling it won't do anything. I might need to head to the dealer and have them reset the ride height.

Mark
'04 XJR

 

[QUOTE=hunter34;731069]ok, I'm beyond myself. Short of bug nuts.

I've replaced just about everything but the steering rack in the front of my '04 XJR. And I still have this rattle in the front suspension. I've replaced the lower control arms, the upper control arms, the sway bar end links, the transmission support mount and the shocks. The hubs check out as do the sway bar bushings. WTF!!!



Have you or anyone else checked the anti-rattle fittings in the front & rear calipers? If missing or damaged the pads will rattle like crazy when not otherwise engaged trying to stop you.

 

What do they look like? I've recently replaced the pads with new Akebonos all the way around. The rattling was there before I replaced the pads, which were about 2 1/2 years old. the rattling just started about 6 months ago. I replaced the pads about 3 months ago.

It's actually more of a clunking than a rattling and I can just barely detect it in my right toes when it happens. Usually between 5 and 40 mph on backroads.

 

The suspension units on each corner are essentially a shock absorber with an

air bag around it and it is possible for the shock absorber to fail and cause a

noise while the air bag is still ok.

I suggest you search this forum for info on how to track this down as a

possible cause of the noise.

 

A clunk is different then a rattle and missing anti-rattle clips usually create a noticeable rattling sound from the effected caliper that you can really hear when you are passing a building or wall that will bounce the sound back to you. At higher speeds it might be unnoticeable due to the rapidity of the movement of the brake pads. When you installed the new pads (if you did it yourself) do you remember installing a thin metal bridge (?) that would have acted as a retainer for the loose fitting pads? They might have looked similar to the misc. parts shown in this Jaguar replacement caliper kit.

A badly installed set could work loose I guess but I don't recall ever seeing that happen.

 

I cut the power at the battery and drained the system of all air and let it sit overnight. I probably didn't need to leave it off that long, but I wanted to make sure I got a proper re-set if one was to be had.

Next morning, I re-connected the battery, and the car rose to 384mm in the front, which I think is the stock setting.

We drove to Chattanooga, TN from Atlanta and back, and I haven't heard the clonking. At all speeds, it's the same buttery smooth steering I remember from when the car only had 42K miles on her.

I'll update later in the week if this remains the case.

 

How do you go about draining the air from the system?

 

Make sure the car is on a perfectly level part of pavement.

Disconnect the battery.

Grab a 10mm open-ended wrench. On the front passenger side of the engine compartment, you will see 5 hard, black hoses terminating into a manifold. One of the hoses will go from the manifold to the top of the passenger side air shock. Pick one of the hoses and disconnect it using the wrench. You'll start to hear a hissing sound as air is released. You don't need to unbolt the hose all the way, just make sure you unbolt it until you get a nice hissing noise.

Sometime after the hissing noise has diminished and the car is sitting down on top of the tires, reconnect the air hose.

Reconnect the battery. Immediately start the car so that the compressor can recharge the system.

Note: This has worked for re-leveling a car that had a "high-side/low-side" kind of problem. It turned out to not be a long term fix for the "clonking". That turned out to be yet another lower-control arm bushing (the ones that mount near the center of the car under the engine nearest the steering rack).

Mark
'04 XJR