Don't laugh... ...I think I have torque steer.
Discussion
I've had the alignment done twice and both time there's been a noticeable improvement, however...
...There's a distinct feeling of change in direction from the rear of the car, especially noticable when backing off the throttle after an overtake for instance. Also, if I change direction at speed, like to change lanes or enter a bend on a motorway, the rear of the car feels a little dislocated from the road.
Now, I'm not expecting it to go like it's on rails like my Zed, but it's a little disquietening to say the least as it doesn't instill confidence when cornering either.
The experience I feel when changing throttle position is, to all intents and purposes, like the feeling of torque steer on a FWD car. It pulls to the right on hard acceleration and dives to the left when backing off.
Any ideas?
Thanks in advance.
...There's a distinct feeling of change in direction from the rear of the car, especially noticable when backing off the throttle after an overtake for instance. Also, if I change direction at speed, like to change lanes or enter a bend on a motorway, the rear of the car feels a little dislocated from the road.
Now, I'm not expecting it to go like it's on rails like my Zed, but it's a little disquietening to say the least as it doesn't instill confidence when cornering either.
The experience I feel when changing throttle position is, to all intents and purposes, like the feeling of torque steer on a FWD car. It pulls to the right on hard acceleration and dives to the left when backing off.
Any ideas?
Thanks in advance.
Tyres and suapension location and control needs looking at. You may have suspension geometry absolutely perfect but this is a static reading and if you have a faulty bush for example will not reflect what's happening under dynamic load. Other thing you can try is swapping tyres front to rear and experimenting with tyre pressures to see what effect this has
Big Rod said:
I've had the alignment done twice and both time there's been a noticeable improvement, however...
...There's a distinct feeling of change in direction from the rear of the car, especially noticable when backing off the throttle after an overtake for instance. Also, if I change direction at speed, like to change lanes or enter a bend on a motorway, the rear of the car feels a little dislocated from the road.
Now, I'm not expecting it to go like it's on rails like my Zed, but it's a little disquietening to say the least as it doesn't instill confidence when cornering either.
The experience I feel when changing throttle position is, to all intents and purposes, like the feeling of torque steer on a FWD car. It pulls to the right on hard acceleration and dives to the left when backing off.
Any ideas?
Thanks in advance.
Rod, you have wear in either your driveshaft U/Js or the rear lower pivot bearings on the hub carrier. This allows the car to steer with the throttle. The driveshaft U/Js also act as the upper track control arms on the rear suspension, so any wear in them will result in constantly changing camber angle: not good!!...There's a distinct feeling of change in direction from the rear of the car, especially noticable when backing off the throttle after an overtake for instance. Also, if I change direction at speed, like to change lanes or enter a bend on a motorway, the rear of the car feels a little dislocated from the road.
Now, I'm not expecting it to go like it's on rails like my Zed, but it's a little disquietening to say the least as it doesn't instill confidence when cornering either.
The experience I feel when changing throttle position is, to all intents and purposes, like the feeling of torque steer on a FWD car. It pulls to the right on hard acceleration and dives to the left when backing off.
Any ideas?
Thanks in advance.
J
jith said:
Rod, you have wear in either your driveshaft U/Js or the rear lower pivot bearings on the hub carrier. This allows the car to steer with the throttle. The driveshaft U/Js also act as the upper track control arms on the rear suspension, so any wear in them will result in constantly changing camber angle: not good!!
J
Well, that makes sense!J
There's visible camber play in the NS rear assembly which the bloke said was the UJ but I couldn't for the life of me think why that would make so much difference and I didn't think would be too much to worry about, but there you go.
So is it a big/expensive job?
Thank you!!
NormanD said:
ALWAYS before having any wheel alignment done have the suspension components checked and replace if required
No point in spending good £££ if there is ANY wear apparent
Like taking a car on a Rolling road with points / plugs etc. nackered and expecting to break all power records
Oh, this I know hence why it's had two new lower arms and a track rod end.No point in spending good £££ if there is ANY wear apparent
Like taking a car on a Rolling road with points / plugs etc. nackered and expecting to break all power records
The worn UJ was a bit of a curveball for me though.
Big Rod said:
jith said:
Rod, you have wear in either your driveshaft U/Js or the rear lower pivot bearings on the hub carrier. This allows the car to steer with the throttle. The driveshaft U/Js also act as the upper track control arms on the rear suspension, so any wear in them will result in constantly changing camber angle: not good!!
J
Well, that makes sense!J
There's visible camber play in the NS rear assembly which the bloke said was the UJ but I couldn't for the life of me think why that would make so much difference and I didn't think would be too much to worry about, but there you go.
So is it a big/expensive job?
Thank you!!
The U/Js are not too bad, but should always be changed in pairs and always mark the shafts before you split them so that you don't alter the balance.
If the car is high mileage, the ideal answer is to replace the hub and swivel bearings both sides and rebuild both driveshafts; but you're talking a few bob to do all that.
J
jith said:
The lower swivels are almost always a pig! You find water gets in and damages everything. The outer bearing track seizes into the alloy housing.
The U/Js are not too bad, but should always be changed in pairs and always mark the shafts before you split them so that you don't alter the balance.
If the car is high mileage, the ideal answer is to replace the hub and swivel bearings both sides and rebuild both driveshafts; but you're talking a few bob to do all that.
J
133k on it. I'll speak to Prestige Jaguar in Paisley and see what they say.The U/Js are not too bad, but should always be changed in pairs and always mark the shafts before you split them so that you don't alter the balance.
If the car is high mileage, the ideal answer is to replace the hub and swivel bearings both sides and rebuild both driveshafts; but you're talking a few bob to do all that.
J
You're quite sure that this will cause the car to steer from the rear yes?
Big Rod said:
jith said:
The lower swivels are almost always a pig! You find water gets in and damages everything. The outer bearing track seizes into the alloy housing.
The U/Js are not too bad, but should always be changed in pairs and always mark the shafts before you split them so that you don't alter the balance.
If the car is high mileage, the ideal answer is to replace the hub and swivel bearings both sides and rebuild both driveshafts; but you're talking a few bob to do all that.
J
133k on it. I'll speak to Prestige Jaguar in Paisley and see what they say.The U/Js are not too bad, but should always be changed in pairs and always mark the shafts before you split them so that you don't alter the balance.
If the car is high mileage, the ideal answer is to replace the hub and swivel bearings both sides and rebuild both driveshafts; but you're talking a few bob to do all that.
J
You're quite sure that this will cause the car to steer from the rear yes?
J
Hi Jith,
I hadn't realised you were a mecahnic. I assume you're familiar with Prestige then too.
In all fairness, I took it for it's first long drive today and it seems much more settled now, but it's still prone to un-nerving squirming on camber changes.
So what do you suggest as a course of action?
TIA.
I hadn't realised you were a mecahnic. I assume you're familiar with Prestige then too.
In all fairness, I took it for it's first long drive today and it seems much more settled now, but it's still prone to un-nerving squirming on camber changes.
So what do you suggest as a course of action?
TIA.
Big Rod said:
Hi Jith,
I hadn't realised you were a mecahnic. I assume you're familiar with Prestige then too.
In all fairness, I took it for it's first long drive today and it seems much more settled now, but it's still prone to un-nerving squirming on camber changes.
So what do you suggest as a course of action?
TIA.
Check out my profile Rod and give me a bell.I hadn't realised you were a mecahnic. I assume you're familiar with Prestige then too.
In all fairness, I took it for it's first long drive today and it seems much more settled now, but it's still prone to un-nerving squirming on camber changes.
So what do you suggest as a course of action?
TIA.
J
Jith could be right about the swivle bearings having play, I too have seen this before. But is easily detectable and pay can be felt not so much side to side but at 4 oclock and 10 oclock.
Part 16 in this pic.
Also as Jith points out the Jag rear end is a bit odd and uses the drive shaft as an upper wishbone, while I have never seen any problem with these, and I worked for jag for 6 years from 1998 to 2006, so I worked on X300 and X308's from new to old, there are so many people that dont bother to grease the nippples which would cause the UJ's to wear out.
The A frame bushes are not always visably faulty, we just learned to do them based on the feel of the car, usually arround 60,000 miles. But sometimes they are so bad you can see the rubber separating from the metal, any movement in these bushes causes the hole rear subframe to move and can give unwanted rear wheel steer.
Parts are only arround £30 each and it take about an hour to remove the A frame and about the same to fanny about getting it into the press and change the bushes. Its been a long time since I have done any but I think we had to glue them in with epoxy resine (Technical bulleting advise to stop them coming out)
No idea if you can poly ones, be carefull poly bushes remove "Jaguarness" from the car.
Part 16 in this pic.
Also as Jith points out the Jag rear end is a bit odd and uses the drive shaft as an upper wishbone, while I have never seen any problem with these, and I worked for jag for 6 years from 1998 to 2006, so I worked on X300 and X308's from new to old, there are so many people that dont bother to grease the nippples which would cause the UJ's to wear out.
The A frame bushes are not always visably faulty, we just learned to do them based on the feel of the car, usually arround 60,000 miles. But sometimes they are so bad you can see the rubber separating from the metal, any movement in these bushes causes the hole rear subframe to move and can give unwanted rear wheel steer.
Parts are only arround £30 each and it take about an hour to remove the A frame and about the same to fanny about getting it into the press and change the bushes. Its been a long time since I have done any but I think we had to glue them in with epoxy resine (Technical bulleting advise to stop them coming out)
No idea if you can poly ones, be carefull poly bushes remove "Jaguarness" from the car.
jith said:
Either you phone me Rod or I'm giving up!
J
I've been up and down the country like a yoyo since Monday Jith and am driving to France tomorrow then down to Italy by Monday.J
I appreciate your offer of help mate, but I've been up to my eyes in it.
Don't worry, I'm not having anything done on the car just yet. The symptoms TT mentioned are spot on mind you.
I'll give you a shout later next week the first chance I get.
Thanks.
Tame Technician said:
Jith could be right about the swivle bearings having play, I too have seen this before. But is easily detectable and pay can be felt not so much side to side but at 4 oclock and 10 oclock.
Part 16 in this pic.
Also as Jith points out the Jag rear end is a bit odd and uses the drive shaft as an upper wishbone, while I have never seen any problem with these, and I worked for jag for 6 years from 1998 to 2006, so I worked on X300 and X308's from new to old, there are so many people that dont bother to grease the nippples which would cause the UJ's to wear out.
The A frame bushes are not always visably faulty, we just learned to do them based on the feel of the car, usually arround 60,000 miles. But sometimes they are so bad you can see the rubber separating from the metal, any movement in these bushes causes the hole rear subframe to move and can give unwanted rear wheel steer.
Parts are only arround £30 each and it take about an hour to remove the A frame and about the same to fanny about getting it into the press and change the bushes. Its been a long time since I have done any but I think we had to glue them in with epoxy resine (Technical bulleting advise to stop them coming out)
No idea if you can poly ones, be carefull poly bushes remove "Jaguarness" from the car.
Very helpful pics TT. Part 16 in this pic.
Also as Jith points out the Jag rear end is a bit odd and uses the drive shaft as an upper wishbone, while I have never seen any problem with these, and I worked for jag for 6 years from 1998 to 2006, so I worked on X300 and X308's from new to old, there are so many people that dont bother to grease the nippples which would cause the UJ's to wear out.
The A frame bushes are not always visably faulty, we just learned to do them based on the feel of the car, usually arround 60,000 miles. But sometimes they are so bad you can see the rubber separating from the metal, any movement in these bushes causes the hole rear subframe to move and can give unwanted rear wheel steer.
Parts are only arround £30 each and it take about an hour to remove the A frame and about the same to fanny about getting it into the press and change the bushes. Its been a long time since I have done any but I think we had to glue them in with epoxy resine (Technical bulleting advise to stop them coming out)
No idea if you can poly ones, be carefull poly bushes remove "Jaguarness" from the car.
I hate to have to admit it, but I've been working on Jags from 1968 until... well, this morning!
The fully independent rear subframe design that utilises the driveshaft as the upper track control arm started life in the MK X in 1960 believe it or not. It has always been an issue for torque steer. The slightest play in any of the U/Js can result in awful handling. On the early system the brakes were inboard on the diff output shafts and there were shims inserted between the discs and the inner joint to set the camber angle.
I remember doing an E Type where the needles had all fallen out of the inner joint and the crosspiece was machining itself through the yoke!! Utterly lethal handling!!
More common than that however is the failure of the bearings and spacer tube, (parts 14-16 in the diagram), in the hub carrier. The seal fails and water gets in very quickly. The inner half of the bearing race then seizes on to the tube and you can't get them out. If you are lucky the bearing will have started to collapse and you can destroy the cage and get the assembly out one way. I have seen these so bad that there are radial cracks around the bearing housing due to the constant hammering when coming on and off the throttle!
The final problem in the later cars when pulling them apart is the utterly, utterly stupid hub nut, (part 8 in the diagram) which has a helicoil insert from new! This means when you remove it the insert falls to bits and it won't go back on.
I have phoned, e mailed, written and badgered Jaguar over the years to get an answer to this ludicrous design, but never received one. Nobody seems to know why you would put an insert into a brand new nut, but they do! If you are reading this Jaguar, how about a proper technical explanation.
Had an XF in for a service yesterday and I see they have completely changed the suspension design. Rear is now canted double wishbone. Back to the good old days, eh!
I look forward to talking to you Rod. Don't work too hard!
J
Gassing Station | Jaguar | Top of Page | What's New | My Stuff