Clonky front end
Discussion
Have noticed that even the smallest pot-holes are producing clonks from my XJR-8 front suspension, any likely causes?
Am hoping it might be ARB drop-links as they are so easy to fit, are these a common problem part?
Or is it more likely wishbone bushes etc?
Any tips would be much appreciated, thanks.
Am hoping it might be ARB drop-links as they are so easy to fit, are these a common problem part?
Or is it more likely wishbone bushes etc?
Any tips would be much appreciated, thanks.
One of the likley causes are the shock absorbers or the top mounting bushes which are easy enough to change. Is it only on one side? Swap the shocks round - and while they are off have a good look at the mounting bushes.
If the shocks and bushes look OK then start looking further by very gently - using just finger and thumb pressure - rocking the steering wheel. If you can feel any slack or play then the chances are the lower column telescopic joint has worn. Start the engine and try again. If you can now feel some play when you couldn't before there may be some wear in the sterering rack. Pull the steering wheel up and down and in and out to check for play. Make sure the two torx bolts on the back of the streering wheel retaining the airbag and horn pad are really tight. These can work loose and cause a sharp rattle over bumps when the steering wheel is even slightly off the straight ahead position.
Jack the front of the car up and see if you can feel any lift on the road wheel by placing a big lever - length of 4x2 is ideal - between the bottom of the tyre and the ground. This will show if there is any slack in the ball joints. Hold the tyre at 12 and 6 o clock and see if there is any play when you try to move it. This checks wheel bearings. Then hold the tyre at 9 and 3 o clock and check for play. This shows any slack in the steering arm ball joints or rack.
Take the wheel off. Have a really good look round all the bushes and joints - you're looking for traces of rust and shiny patches on the bushes or components that indicate excessive movement. Go through all the bushes and ball joints with a tyre lever to see if you can get any movement or slack.
Finally, check the 'bleedin obvious. Are the wheel nuts all tight? Some Scumbag may have tried to help himself to your wheels. There's nothing rattling about in the glovebox or under the bonnet is there?
British Car Parts have an excellent site where you can see and buy all the individual bushes and joints for the XJ's suspension.
Locating random rattles can be a bit of a PITA and takes paitence and time. If you're really stuck for either or both, why not book the car in for an MOT (cheapest way of getting the car checked) and let a experienced mechanic give the front suspension the once over. If there's anythig amiss chances are he'll find it.
There, that's your weekend spoilt
HTH
If the shocks and bushes look OK then start looking further by very gently - using just finger and thumb pressure - rocking the steering wheel. If you can feel any slack or play then the chances are the lower column telescopic joint has worn. Start the engine and try again. If you can now feel some play when you couldn't before there may be some wear in the sterering rack. Pull the steering wheel up and down and in and out to check for play. Make sure the two torx bolts on the back of the streering wheel retaining the airbag and horn pad are really tight. These can work loose and cause a sharp rattle over bumps when the steering wheel is even slightly off the straight ahead position.
Jack the front of the car up and see if you can feel any lift on the road wheel by placing a big lever - length of 4x2 is ideal - between the bottom of the tyre and the ground. This will show if there is any slack in the ball joints. Hold the tyre at 12 and 6 o clock and see if there is any play when you try to move it. This checks wheel bearings. Then hold the tyre at 9 and 3 o clock and check for play. This shows any slack in the steering arm ball joints or rack.
Take the wheel off. Have a really good look round all the bushes and joints - you're looking for traces of rust and shiny patches on the bushes or components that indicate excessive movement. Go through all the bushes and ball joints with a tyre lever to see if you can get any movement or slack.
Finally, check the 'bleedin obvious. Are the wheel nuts all tight? Some Scumbag may have tried to help himself to your wheels. There's nothing rattling about in the glovebox or under the bonnet is there?
British Car Parts have an excellent site where you can see and buy all the individual bushes and joints for the XJ's suspension.
Locating random rattles can be a bit of a PITA and takes paitence and time. If you're really stuck for either or both, why not book the car in for an MOT (cheapest way of getting the car checked) and let a experienced mechanic give the front suspension the once over. If there's anythig amiss chances are he'll find it.
There, that's your weekend spoilt
HTHThanks Steve, just passed MOT last week, so nothing with too much play. Just seems clonky compared to my previous XJR. Am running on the low side of tyre pressure recommendations for max comfort, doesnt seem to glide over the holes quite as well.
Will do some investigation at the weekend, cheers.
Will do some investigation at the weekend, cheers.
Jaguar steve said:
Hmmm 
Very strange things Jaguar recommended tyre pressures IMO.
Like you, I've tried the comfort pressures and found that it seems to make little difference to the ride quality - but go just 1 or 2 psi below and the car feels absolutely terible.
I'm convinced the whole dynaminc of my XJ on sports suspension and 17" Celtics is at it's best with the fronts a couple of psi below the full load pressure and the rears at the full pressure. Strangely enough this actually improves the overall ride quality and I suspect the tyres at the higher pressure are actually feeding enough movement and energy into the suspension to allow it to damp effectively over smaller bumps rather than just dissapating small bumps by flexing the tyre sidewall with no input to the suspension.
There are instances where poor quality tyres or faulty geometry can cause road noise and bumps to feed through the suspension. There's nothing actually wrong with any of the components, but change the tyres, or set the geometry correctly and the noise disappears. Problem is with such a smooth and refined car as an XJ - and everybody's very high expections of it given Jaguars reputation for ride and refinement - when this happens it's easy to get convinced there's a problem somewhere in the suspension when actually there is not.
Have a play with tyre pressures and check the shocks and bushes first. Best of all that's the easiest thing to do as well.
Very strange things Jaguar recommended tyre pressures IMO.Like you, I've tried the comfort pressures and found that it seems to make little difference to the ride quality - but go just 1 or 2 psi below and the car feels absolutely terible.
I'm convinced the whole dynaminc of my XJ on sports suspension and 17" Celtics is at it's best with the fronts a couple of psi below the full load pressure and the rears at the full pressure. Strangely enough this actually improves the overall ride quality and I suspect the tyres at the higher pressure are actually feeding enough movement and energy into the suspension to allow it to damp effectively over smaller bumps rather than just dissapating small bumps by flexing the tyre sidewall with no input to the suspension.
There are instances where poor quality tyres or faulty geometry can cause road noise and bumps to feed through the suspension. There's nothing actually wrong with any of the components, but change the tyres, or set the geometry correctly and the noise disappears. Problem is with such a smooth and refined car as an XJ - and everybody's very high expections of it given Jaguars reputation for ride and refinement - when this happens it's easy to get convinced there's a problem somewhere in the suspension when actually there is not.
Have a play with tyre pressures and check the shocks and bushes first. Best of all that's the easiest thing to do as well.
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