Unstable at high speed
#21
I have been following this thread with interest, and on the one hand can see that you have been offered much well intentioned and good advice, but on the receiving end it might all be a bit confusing and depressing!
Before throwing in the towel and handing the car off to someone else to "fix' i wonder whether it might be worth another attempt to more accurately diagnose the problem.
You say that everything is fine up to 60mph, which I would take to mean no knocks, rattles, vibrations or waywardness in the steering. You have not mentioned any knocking or rattling over bumps. At face value, this is good, and starts to point the finger away from the dreaded topic of bushes!
You mention that an upper ball joint is worn. I would replace it without delay, as it is cheap and fairly straightforward to do. If it isnt causing a problem up to 60, I doubt that it is the culprit, but it needs fixed, and is a distraction.
You mention that by 100mph, the problem is fully apparent. Do you have any recollection of how it was at 70? 80? 90?. I am not advocating that you drive it at these speeds again, as it all sounds rather dangerous, but if the problem came on progressively, I would start to think of the variable assistance aspect of the steering rack. In short, the amount of assistance is intended to vary with speed, the faster you go, the less assistance you get. If there was something sticking in your steering, you might be able to turn the wheel through it with power assistance, but not without. So when you reach a high enough speed for the power assistance to diminish sufficiently, the steering becomes sticky to turn. If you can jack the car up with both front wheels off the ground, you could try moving the steering from lock to lock with the engine off, to establish whether there is full range of movement and it is smooth.
Another thought might be to put the car in for whatever for of government inspection you have. I sometimes put a car in for an MoT test here, as it is a cheap way to get the brakes, ball joints and bushes etc checked over by an expert
Before throwing in the towel and handing the car off to someone else to "fix' i wonder whether it might be worth another attempt to more accurately diagnose the problem.
You say that everything is fine up to 60mph, which I would take to mean no knocks, rattles, vibrations or waywardness in the steering. You have not mentioned any knocking or rattling over bumps. At face value, this is good, and starts to point the finger away from the dreaded topic of bushes!
You mention that an upper ball joint is worn. I would replace it without delay, as it is cheap and fairly straightforward to do. If it isnt causing a problem up to 60, I doubt that it is the culprit, but it needs fixed, and is a distraction.
You mention that by 100mph, the problem is fully apparent. Do you have any recollection of how it was at 70? 80? 90?. I am not advocating that you drive it at these speeds again, as it all sounds rather dangerous, but if the problem came on progressively, I would start to think of the variable assistance aspect of the steering rack. In short, the amount of assistance is intended to vary with speed, the faster you go, the less assistance you get. If there was something sticking in your steering, you might be able to turn the wheel through it with power assistance, but not without. So when you reach a high enough speed for the power assistance to diminish sufficiently, the steering becomes sticky to turn. If you can jack the car up with both front wheels off the ground, you could try moving the steering from lock to lock with the engine off, to establish whether there is full range of movement and it is smooth.
Another thought might be to put the car in for whatever for of government inspection you have. I sometimes put a car in for an MoT test here, as it is a cheap way to get the brakes, ball joints and bushes etc checked over by an expert
The car already passed it's MOT some months ago and they didn't comment on any of this even though they were thourogh. Had some issues with high Co reading but that is fixed and another story.
A friend of mine has some experience and I'll probably try to sort this with his help. Hopefully soon.
I did btw notice that the famous edd China from the BBC program wheeler dealers has now married a girl from Norway, so maybe I can lure him here to come and restore this British icon, now rolling through the streets of norway😂😅😊.
#22
We just changed the ball joint and the upper wishbone bushes . It definitely helped and totally removed a clunking sensation at the steering wheel. Do I need a new alignment now? We did rearrange the shims to match the illustration from the technical drawing though as they were placed in different order.
One new in position here..It feels better now but the steering is still vague at high speeds. It does not drift as easily but small corrections on the steering wheel aren't always noticed until it suddenly changes direction just a bit too much.
I think I will once again try and fit that nylon shims kit I purchased for the steering rack..
Drove it to work and tried to race the train as well.. I lost 😅
One new in position here..It feels better now but the steering is still vague at high speeds. It does not drift as easily but small corrections on the steering wheel aren't always noticed until it suddenly changes direction just a bit too much.
I think I will once again try and fit that nylon shims kit I purchased for the steering rack..
Drove it to work and tried to race the train as well.. I lost 😅
#23
Good job! If you were careful to replace the shims as you found them, I wouldn't be rushing to get the alignment checked just yet.
Did you try turning the steering from lock to lock with both wheels off the ground and the engine off ( i.e. No power assistance)?
It would be useful to establish that your steering has free and smooth operation from lock to lock without assistance from the pump.
Did you try turning the steering from lock to lock with both wheels off the ground and the engine off ( i.e. No power assistance)?
It would be useful to establish that your steering has free and smooth operation from lock to lock without assistance from the pump.
#24
#25
#26
I would definitely do both sides of the car with any suspension items! Even if the bush appears in ok condition, the rubber will have deteriorated since new and will behave differently to the replacement part.
On my XJR, have three shims in front of and one behind the top ball joint. I have a slight vagueness in the steering despite having replaced all the bushes and ball joints and correctly adjusting the wheel bearings. I plan to fit the steering rack shims this weekend in the hope of sorting it.
I know that my rear toe needs setting, does anyone know what it should be?
On my XJR, have three shims in front of and one behind the top ball joint. I have a slight vagueness in the steering despite having replaced all the bushes and ball joints and correctly adjusting the wheel bearings. I plan to fit the steering rack shims this weekend in the hope of sorting it.
I know that my rear toe needs setting, does anyone know what it should be?
#27
Please be aware that these shims you are discussing are of different thicknesses, namely 0.8mm, 1.2mm & 1.6mm. Castor adjustment is obtained by swapping them around appropriately back & front to get required total thickness back or front & thus obtain required castor adjustment.
The Toe adjustment for the rear is +4.36mm to -0.6mm.
I have successfully carried out my own front wheel alignment using a "Longacre" camber/castor tool & "Trackace" laser toe alignment tool & consider my steering to be spot on with no issues at all.
John Herbert
(1996 Jaguar XJR)
The Toe adjustment for the rear is +4.36mm to -0.6mm.
I have successfully carried out my own front wheel alignment using a "Longacre" camber/castor tool & "Trackace" laser toe alignment tool & consider my steering to be spot on with no issues at all.
John Herbert
(1996 Jaguar XJR)
#28
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#31
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At least three thicknesses were offered...all show NLA from Jaguar at the moment. I suspect there are other suppliers
https://www.jaguarclassicparts.com/u...pper-and-lower
The shims serve two purposes-- to allow caster adjustment and to maintain correct spacing between the ball joint and the control arms.
Seems to me that the total thickness of the shim stack should be measured and maintained. You can use shims of different thickness and place them on either side of the BJ, obviously, but the overall thickness of the stack should be maintained.
Cheers
DD
https://www.jaguarclassicparts.com/u...pper-and-lower
The shims serve two purposes-- to allow caster adjustment and to maintain correct spacing between the ball joint and the control arms.
Seems to me that the total thickness of the shim stack should be measured and maintained. You can use shims of different thickness and place them on either side of the BJ, obviously, but the overall thickness of the stack should be maintained.
Cheers
DD
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JohnXJR6 (06-23-2017)
#32
John XJR6 yes the mm refers to the total difference (Total toe) between the rear & front of the wheel measurement, not each individual wheel. Plus refers to Toe In & Minus refers to Toe Out.
Doug I have attached details on shims & adjusting Caster.
I did fail to mention earlier that you will also require (most important & essential actually) a pair of turntables, rather expensive unfortunately.
I have made a pair myself from suitable ply using the largest lazy Suzanne turntable I could purchase & marked them with the required angles etc.
They work fine & material cost very cheap. ( Photo attached)
My own car originally pulled slightly to the left & to correct I eventually ended up with the following adjustment which gave me approx. 5 degree positive caster each side (with in specs & giving good straightline stability)
LEFT WHEEL Total shim thickness
Front of Ball joint 4mm
Rear of Ball joint 0.8mm
RIGHT WHEEL
Front of Ball joint 0.0mm
Rear of Ball joint 4.8mm
Yes, right wheel required no shims at the front at all, you have to juggle the 4 shims to obtain appropriate thickness, and cannot use more or less than the 4 shims as indicated in the extract from a Technical bulletin.
Caster is the main adjustment that effects vehicle pulling either left or right & has a big impact on straightline stability, especially if it is biased towards the positive.
Also Dough I did take the plunge & fitted 225/55R17 Bridgestone tyres to my XJR with great results, absolutely no tramlining, slightly better ground clearance & tyre fitters commented they looked fine on vehicle. Much better suited to our Aussie roads overall.
John Herbert
(1996 Jaguar XJR)
John Herbert
Doug I have attached details on shims & adjusting Caster.
I did fail to mention earlier that you will also require (most important & essential actually) a pair of turntables, rather expensive unfortunately.
I have made a pair myself from suitable ply using the largest lazy Suzanne turntable I could purchase & marked them with the required angles etc.
They work fine & material cost very cheap. ( Photo attached)
My own car originally pulled slightly to the left & to correct I eventually ended up with the following adjustment which gave me approx. 5 degree positive caster each side (with in specs & giving good straightline stability)
LEFT WHEEL Total shim thickness
Front of Ball joint 4mm
Rear of Ball joint 0.8mm
RIGHT WHEEL
Front of Ball joint 0.0mm
Rear of Ball joint 4.8mm
Yes, right wheel required no shims at the front at all, you have to juggle the 4 shims to obtain appropriate thickness, and cannot use more or less than the 4 shims as indicated in the extract from a Technical bulletin.
Caster is the main adjustment that effects vehicle pulling either left or right & has a big impact on straightline stability, especially if it is biased towards the positive.
Also Dough I did take the plunge & fitted 225/55R17 Bridgestone tyres to my XJR with great results, absolutely no tramlining, slightly better ground clearance & tyre fitters commented they looked fine on vehicle. Much better suited to our Aussie roads overall.
John Herbert
(1996 Jaguar XJR)
John Herbert
#33
I'm baffled and utterly surprised now.
Returned to the garage and rented it for an hour. The steering turned smooth from lock to lock without any issues so that's all good. I brought with me the steering rack stiffening bushes again and decided to give it another go.
These nylon shims were quite flexible.. fortunately.
i thought to myself again that these could not possibly fit. And when I turned the wheel there wasn't any change in the gap.
Anyway, I decided to go for it, so I cursed and wrestled them into position more or less with some force and determination. I could not believe they would possibly do any difference at all so I just didn't care if they broke or didn't fit perfectly.
30 minutes later they were both in place, but they sat so damn tight I didn't even bother trying to attach the steel wire that came with the shims.
Not my photo but it looked a bit like this, minus the steel wire.
So, I left the garage, headed for the highway to get home, and MY God there was actually a big difference now in the responsiveness in the steering. More precise, sharper and less of that tramlining sensation. I almost believe now that I've cured this issue. I still haven't gotten a new alignment after I changed the ball joint and the upper wishbone bushes, but I guess after that it will be 100%
Very happy about this.
Returned to the garage and rented it for an hour. The steering turned smooth from lock to lock without any issues so that's all good. I brought with me the steering rack stiffening bushes again and decided to give it another go.
These nylon shims were quite flexible.. fortunately.
i thought to myself again that these could not possibly fit. And when I turned the wheel there wasn't any change in the gap.
Anyway, I decided to go for it, so I cursed and wrestled them into position more or less with some force and determination. I could not believe they would possibly do any difference at all so I just didn't care if they broke or didn't fit perfectly.
30 minutes later they were both in place, but they sat so damn tight I didn't even bother trying to attach the steel wire that came with the shims.
Not my photo but it looked a bit like this, minus the steel wire.
So, I left the garage, headed for the highway to get home, and MY God there was actually a big difference now in the responsiveness in the steering. More precise, sharper and less of that tramlining sensation. I almost believe now that I've cured this issue. I still haven't gotten a new alignment after I changed the ball joint and the upper wishbone bushes, but I guess after that it will be 100%
Very happy about this.
Last edited by Tcasmarcus; 07-10-2017 at 03:49 PM.
#34
#35
I'm baffled and utterly surprised now.
Returned to the garage and rented it for an hour. The steering turned smooth from lock to lock without any issues so that's all good. I brought with me the steering rack stiffening bushes again and decided to give it another go.
These nylon shims were quite flexible.. fortunately.
i thought to myself again that these could not possibly fit. And when I turned the wheel there wasn't any change in the gap.
Anyway, I decided to go for it, so I cursed and wrestled them into position more or less with some force and determination. I could not believe they would possibly do any difference at all so I just didn't care if they broke or didn't fit perfectly.
30 minutes later they were both in place, but they sat so damn tight I didn't even bother trying to attach the steel wire that came with the shims.
Not my photo but it looked a bit like this, minus the steel wire.
So, I left the garage, headed for the highway to get home, and MY God there was actually a big difference now in the responsiveness in the steering. More precise, sharper and less of that tramlining sensation. I almost believe now that I've cured this issue. I still haven't gotten a new alignment after I changed the ball joint and the upper wishbone bushes, but I guess after that it will be 100%
Very happy about this.
Returned to the garage and rented it for an hour. The steering turned smooth from lock to lock without any issues so that's all good. I brought with me the steering rack stiffening bushes again and decided to give it another go.
These nylon shims were quite flexible.. fortunately.
i thought to myself again that these could not possibly fit. And when I turned the wheel there wasn't any change in the gap.
Anyway, I decided to go for it, so I cursed and wrestled them into position more or less with some force and determination. I could not believe they would possibly do any difference at all so I just didn't care if they broke or didn't fit perfectly.
30 minutes later they were both in place, but they sat so damn tight I didn't even bother trying to attach the steel wire that came with the shims.
Not my photo but it looked a bit like this, minus the steel wire.
So, I left the garage, headed for the highway to get home, and MY God there was actually a big difference now in the responsiveness in the steering. More precise, sharper and less of that tramlining sensation. I almost believe now that I've cured this issue. I still haven't gotten a new alignment after I changed the ball joint and the upper wishbone bushes, but I guess after that it will be 100%
Very happy about this.
#37
.
I thought I had mentioned the 1059 spacers but looking back it must have been someone else . Thanks for the source for Lady P has quite the gap and I knew it had to be an issue with mine . I was going to make them myself . The trick is to turn the wheel so the assembly walks from side to side in the mounts ?
Working on the Stereo LED messed up digits now
I thought I had mentioned the 1059 spacers but looking back it must have been someone else . Thanks for the source for Lady P has quite the gap and I knew it had to be an issue with mine . I was going to make them myself . The trick is to turn the wheel so the assembly walks from side to side in the mounts ?
Working on the Stereo LED messed up digits now
Last edited by Lady Penelope; 09-09-2017 at 04:36 PM.
#38
just an update. the nylon shims greatly improved the ride. I still have a bit of a vague steering sensation because i guess the rack is worn. I now have also changed all 4 shocks and the rear spring isolators and that completely removed the feeling of an unstable car at high speeds. I guess some speeding tickets are now coming up..
Next up are all the front suspension bushings and the balljoints etc.
Next up are all the front suspension bushings and the balljoints etc.
#39
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Lady Penelope (09-22-2018)
#40
Quick and dirty steering rack spacer. Jack up one side of the front. Put a stand under the car. Key on but dont start. have someone crank the wheel one direction and one side will open up. (You might see if your spacers fit at this point!) I used a few plastic wire ties in the gap. Crank the wheel the other day....more wire ties. (or your spacer).
Makes a big difference.
Also check your tie rods. (Shop probably did when they did alignment but who knows?)
Look at you upper front wishbones...you will see spacer between the ball joints and the arms. Moving the spacers forward moves the ball joint aft and increases caster. Caster increases self centering feel. Usually you will find one side has all the spacers up front and the other side set to match the one that is out of adjustment. but if you find one spacer on each side the same thickness that is in the back position and you can move it to front postion and add camber easy.
Me too... (95 VDP) New rear soft bilsteins still seem way to soft in rebound. I may just swap rears.
I have a set of XJR sways I have yet to install too.
Makes a big difference.
Also check your tie rods. (Shop probably did when they did alignment but who knows?)
Look at you upper front wishbones...you will see spacer between the ball joints and the arms. Moving the spacers forward moves the ball joint aft and increases caster. Caster increases self centering feel. Usually you will find one side has all the spacers up front and the other side set to match the one that is out of adjustment. but if you find one spacer on each side the same thickness that is in the back position and you can move it to front postion and add camber easy.
I have a set of XJR sways I have yet to install too.
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Scotlad (09-23-2018)