1986 Jaguar XJS wondering steering help
#21
I've recently had the front and rear suspensions rebuilt in my XJS.
Front - new upper and lower bushings (OEM rubber), new ball joints (lemforder), new tie rod ends, GAZ shocks, new OEM springs to restore ride height, new subframe mounts
Rear - new fulcrum bearings, diff output shaft bearings, radius arm bushing (OEM rubber), Gaz shocks etc
The steering rack bushes were replaced around 12 months ago when the rack was rebuilt. They are poly.
Unfortunately the car doesn't drive as well as I'd hoped. Straight line stability could be better and the steering feels a bit vague/light at speed or under hard acceleration
The car runs 16 inch tyres from a later model XJS. 225/60 R16 rear and 225/55 R16 front.
Alignment is:
Front
Camber left and right is around -0.5deg
Caster is around 2.5deg left and right
Total Toe is +1.1mm
Rear
Camber, slightly negative but almost Nil
Total Toe +1.5mm
My first inclination is more caster is required and maybe some toe in rather than the current 1.1mm toe out. I've read comments where posters say to dial up the caster to the max spec. Can anyone advise how high this is? Any other suggestions? Thanks
Front - new upper and lower bushings (OEM rubber), new ball joints (lemforder), new tie rod ends, GAZ shocks, new OEM springs to restore ride height, new subframe mounts
Rear - new fulcrum bearings, diff output shaft bearings, radius arm bushing (OEM rubber), Gaz shocks etc
The steering rack bushes were replaced around 12 months ago when the rack was rebuilt. They are poly.
Unfortunately the car doesn't drive as well as I'd hoped. Straight line stability could be better and the steering feels a bit vague/light at speed or under hard acceleration
The car runs 16 inch tyres from a later model XJS. 225/60 R16 rear and 225/55 R16 front.
Alignment is:
Front
Camber left and right is around -0.5deg
Caster is around 2.5deg left and right
Total Toe is +1.1mm
Rear
Camber, slightly negative but almost Nil
Total Toe +1.5mm
My first inclination is more caster is required and maybe some toe in rather than the current 1.1mm toe out. I've read comments where posters say to dial up the caster to the max spec. Can anyone advise how high this is? Any other suggestions? Thanks
#22
Toe should be 0 to 1/2 a degree toe in (not sure what the + in "+1.1mm" means). Castor spec is 3.5 degrees positive + or - 0.25 of a degree, so you need about a degree more castor.
Also, some alignment places do not understand the correct procedure for toe in/out adjustment, which is:
Centre rack using the indentation
Adjust each side separately to the correct spec (I would suggest 1/2 a degree toe in).
Some places do all the adjustment on one side, whereupon the power steering is fighting the toe.
The rear toe (assuming + means toe in) is a bit more than spec which is parallel, but there is not much you can do about it, and it may go nearer to spec as the rubber beds in. However I would adjust the rear camber to 0.5 to 0.75 degrees negative, as this vastly improves the cornering grip and solid feel of the rear end. This is adjusted by removing shims from the drive shaft/brake disc/ differential flange join.
Also, some alignment places do not understand the correct procedure for toe in/out adjustment, which is:
Centre rack using the indentation
Adjust each side separately to the correct spec (I would suggest 1/2 a degree toe in).
Some places do all the adjustment on one side, whereupon the power steering is fighting the toe.
The rear toe (assuming + means toe in) is a bit more than spec which is parallel, but there is not much you can do about it, and it may go nearer to spec as the rubber beds in. However I would adjust the rear camber to 0.5 to 0.75 degrees negative, as this vastly improves the cornering grip and solid feel of the rear end. This is adjusted by removing shims from the drive shaft/brake disc/ differential flange join.
Last edited by Greg in France; 03-18-2019 at 02:06 AM.
#23
#24
Thanks for your responses. I had the toe back to front, I double checked and a positive toe reading is actually toe in, so I do have a small amount of toe-in front and rear. Converted to degrees for a 16inch wheel its about 0.17 deg toe-in on the front and 0.2 deg toe-in on the rear. Perhaps the front could do with a bit more.
I will also get more caster added
As for the rear camber, it's currently -0.18deg on the left and -0.37deg on the right. Your comments are noted Greg, although I might try and stick to the front adjustments (or should I say easier adjustments) first.
I will also get more caster added
As for the rear camber, it's currently -0.18deg on the left and -0.37deg on the right. Your comments are noted Greg, although I might try and stick to the front adjustments (or should I say easier adjustments) first.
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Greg in France (03-18-2019)
#27
Did you put full weight on the car and settle the front suspension before you tightened the lower fulcrum shaft? Failure to do this will distort the lower wishbone bushes and will cause premature failure.
Yep the stub axle is very common, both mine were like that. I fixed this by machining spacers that fit between the inner and outer bearing to prevent them from spinning. They also set end float both sides, all I need to do is tighten the nut and install the castle cap and split pin
BTW Greg I had the whole thing apart recently to replace the front disks and the spacers I made between the front and rear bearings are still good.
Yep the stub axle is very common, both mine were like that. I fixed this by machining spacers that fit between the inner and outer bearing to prevent them from spinning. They also set end float both sides, all I need to do is tighten the nut and install the castle cap and split pin
BTW Greg I had the whole thing apart recently to replace the front disks and the spacers I made between the front and rear bearings are still good.
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Greg in France (03-19-2019)
#28
#29
The drag brace elestormatic puck on the forward drag braces are cracked
order new elestricmeric pucks press them in and no more drifting when you step on it.
Asumming you have checked the rear wheel and with the car jacked up grab the wheel try to move it in and out.
If it is realy bad you can do it with out jacking it up.
order new elestricmeric pucks press them in and no more drifting when you step on it.
Asumming you have checked the rear wheel and with the car jacked up grab the wheel try to move it in and out.
If it is realy bad you can do it with out jacking it up.
#30
That is good news; I reckon, as you said previously, they need to be made of hard steel, mine were normal mild steel. But now, as I have rebuilt the entire front end including a new subframe and all new parts, and as I eventually found the real trouble was the front six shots which I hardened up, and as it is absolutely perfect to drive, I shall not be doing any more to it!
#31
Greg
#34
#35
Rear front subframe mounts are fine OEM, no poly ones as they are not needed.
#36
Ok, gotcha...I guess no way to stop the side to side motion of the stock ones if that is the major issue with them? I'd be more than happy to install the poly ones but don't want to get that stiff ride that many complain about. Perhaps you'd only feel that kind of stiffness when applied to control arm bushings and that sort.
#37
Ok, gotcha...I guess no way to stop the side to side motion of the stock ones if that is the major issue with them? I'd be more than happy to install the poly ones but don't want to get that stiff ride that many complain about. Perhaps you'd only feel that kind of stiffness when applied to control arm bushings and that sort.