V8 XJR - very odd noises!
Discussion
Hi there gents,
Let me start by saying that although I love cars, I am no mechanic, so please don't laugh at me too much if the answer to this is blindingly obvious!
My XJR has developed a series of very odd noises. I'll try to describe them in my best non technical way: The most prominent noise sounds like a rotating part that should be round has become elliptical and is fouling aginst something for about a quarter of its cycle. It only happens when the car is moving and the frequency increases with the speed. The noise seems to be coming from below me - possibly from outside the car.
In fact it sounds a bit like a steam engine - you know, a slow 'chuff-chuff' at low speeds that speeds up as the car does. Initially it is worse at 40-60 mph. Below that it was less pronounced, although definitely there, and at 70 it seems to even itself out.
The only effect it has on the way the car drives is a wobble at the steering wheel. After about half an hour of driving the noise stopped for a couple of minutes, then came back again, but much more irregularly. It would 'chuff' or foul every 30 - 45 seconds or so, but when it did the wheel noticeably jerked to right. Then it stopped again for a minute or two then it went back to how it was before.
On arrival at my destination I had to make a few turns. On the right turns there was a horrible graunching sound, but none on the left turns.
Then there was a horrible sqealing as I drove onto site at about 10 mph.
My first thoughts were something to do with the propshaft and its UJs. Then I thought that possible I had a cracked brake disc - as I've had similar syptoms with an old XJS. Could it be something fouling the steering?
In essence, HELP!
Mant thanks for any advice you guys can offer.
Let me start by saying that although I love cars, I am no mechanic, so please don't laugh at me too much if the answer to this is blindingly obvious!
My XJR has developed a series of very odd noises. I'll try to describe them in my best non technical way: The most prominent noise sounds like a rotating part that should be round has become elliptical and is fouling aginst something for about a quarter of its cycle. It only happens when the car is moving and the frequency increases with the speed. The noise seems to be coming from below me - possibly from outside the car.
In fact it sounds a bit like a steam engine - you know, a slow 'chuff-chuff' at low speeds that speeds up as the car does. Initially it is worse at 40-60 mph. Below that it was less pronounced, although definitely there, and at 70 it seems to even itself out.
The only effect it has on the way the car drives is a wobble at the steering wheel. After about half an hour of driving the noise stopped for a couple of minutes, then came back again, but much more irregularly. It would 'chuff' or foul every 30 - 45 seconds or so, but when it did the wheel noticeably jerked to right. Then it stopped again for a minute or two then it went back to how it was before.
On arrival at my destination I had to make a few turns. On the right turns there was a horrible graunching sound, but none on the left turns.
Then there was a horrible sqealing as I drove onto site at about 10 mph.
My first thoughts were something to do with the propshaft and its UJs. Then I thought that possible I had a cracked brake disc - as I've had similar syptoms with an old XJS. Could it be something fouling the steering?
In essence, HELP!
Mant thanks for any advice you guys can offer.
Edited by BruceV8 on Monday 9th September 12:14
Random steering movements suggests something is seriously wrong with the front suspension. I suggest you stop driving it.
The noises you describe may be brake pads worn down to the metal, loose wheel nuts, a badly damaged tyre or possibily a disintigrating wheel bearing or maybe even partially collapsed suspension allowing a wheel to foul the bodywork. I doubt it's a prop or driveshaft problem
Either way it needs looking at urgently.
The noises you describe may be brake pads worn down to the metal, loose wheel nuts, a badly damaged tyre or possibily a disintigrating wheel bearing or maybe even partially collapsed suspension allowing a wheel to foul the bodywork. I doubt it's a prop or driveshaft problem
Either way it needs looking at urgently.
Ok slight update. I drove the car a short distance before I got to read Steve's post.
The 'chuff' was replaced by a constant grinding sound that would last for a few minutes then go silent. After a few minutes it would start again. There was also a squeaking sound. Just before I finsihed driving the 'chuff' came back. The constant grinding made me think that perhaps a wheel bearing had gone, but when I stopped a chap who was watching me said that the squeak was coming from the front left wheel and so was a horrible smell. So now I'm thinking along the lines of a binding brake caliper. Could that be right? The car was parked up for about a month before I drove it this morning.
The 'chuff' was replaced by a constant grinding sound that would last for a few minutes then go silent. After a few minutes it would start again. There was also a squeaking sound. Just before I finsihed driving the 'chuff' came back. The constant grinding made me think that perhaps a wheel bearing had gone, but when I stopped a chap who was watching me said that the squeak was coming from the front left wheel and so was a horrible smell. So now I'm thinking along the lines of a binding brake caliper. Could that be right? The car was parked up for about a month before I drove it this morning.
Yes it could be, especially if the car has been standing for a while prior to you driving it today. Feel all the wheels - if one is abnormally hot then that's almost certainly a binding caliper that you have and it's ground the pads down to the metal - that would explain the grinding noise on different steering locks too. If there's an excess of brake dust on one wheel and a bitter burning smell those are more clues too.
That may also account for the random steering movement too as you'll have an uneven braking effort causing the car to pull or self steer towards the side that's still working OK. But that really needs investigating to completely rule out any other problem.
I'd say the car is not safe to drive and ought to be recovered.
That may also account for the random steering movement too as you'll have an uneven braking effort causing the car to pull or self steer towards the side that's still working OK. But that really needs investigating to completely rule out any other problem.
I'd say the car is not safe to drive and ought to be recovered.
Edited by Jaguar steve on Monday 9th September 12:38
BruceV8 said:
Got it home (on the back of a recovery truck). I'm pretty sure the its the caliper carrier rubbing against the outer surface of the brake disc.
Thanks for your help, Steve.
You're welcome Thanks for your help, Steve.
I'd be surprised if it's the caliper bracket at fault - unless it's broken or the retaining bolts to the hub have come undone
. Chances are whatever you'll need new pads and discs. I'd suggest you avoid the pattern cheap ones and replace with either genuine Jaguar or a reputable O/E supplier. I've had nothing but grief over the years from cheap Jaguar discs.If the caliper has siezed it'll need replacing. If it's just the piston has come out too far due to seriously worn pads and then twisted in the caliper bore then it is usually OK to carefully ease it back in.
Suggest you have the brake fluid changed too if it's more than two/three years old.
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