Wheelspin On Slow Corners Have I Overcooked The Suspension? XJS V12
 

Hi Guys

Having Custom made some 'Shock Absorber Bushes' out of a harder but same material as the OEM.

They have Transformed the handling of my Car

All the Rattles,Bangs and Squeaks, have totally disappeared and She no longer Wallows around like a drunken Sailor!

In fact I would go as far as to say She doesn't Roll at all!

Which in one way is brilliant as for once She handles like a proper Sports Car and I can drive her really Hard and Fast!

In some ways She reminds me of the Lotus Elan I used to have, obviously not exactly the same, as handling wise the Lotus was in a Class of it own.

But yesterday I took her for a proper full on Test Drive through the Essex Countryside, down some really amazing Country Lanes.

She was blasting through Corners just like a Rocket on wheels!

But once on proper Tarmac, I was getting Tyre Squeal on Roundabouts even at very slow speeds.

Is that Supposed to happen?

I'm tempted to make another Set of Shock Absorber Bushes, which are a little bit Closer to the OEM but I have to admit I'm addicted to the way She handles now!

The only problem being, I cannot see that my Tyres will last very long, even though the Car is now an absolute 'Joy' to drive.

Not sure which way to jump guys, so I would welcome some advice

I would guess the alignment is knackered. Have you checked this? Haven't had mine done, but I hear its "touchy".
Pete

OB
Are we talking rear wheel spin, or front wheel tyre squeal? If front tyre squeal, the bushes are nothing to do with the squeal. You are just driving the car faster and cornering more energetically now that the car's damping is working as intended. Your tyres are doing more and they are squealing about it!

There are technical reasons for low speed front wheel squeal on bone dry surfaces, as in a multi-storey car park, if you were going really slowly. Getting the toe set up could not hurt, but finding someone who can do it properly on an XJS is another story. If she tracks though long fast corners well at speed, and does not wander or pull, leave well alone...

If it is an inside rear tyre spinning, get ready to change the diff as the LSD is not LS-ing, or if both are spinning on dry tarmac, the tyres are hardened off and cannot deal with the traction now that you are nailing it! If the diff, Ward Engineering in Colchester will rebuild one for you!

Greg

OB,

My first thought would be the tyres. How old are they? That type of squeal is something I recently had on some Pirellis which had great tread but had become somewhat block hardened and, when removed, the cracking that was only now visible at the tread joint was positively worrying!

I think you would be quite unlucky if it's the LSD that has packed up.

Good luck with sorting it.

Paul

OMG! I might be a bit of a 'Chancer' Paul but even I would not even drive a 100 yards on those!

As for the LSD it's not that, the tyre squeal is on the front, something is wrong somewhere and think that 'Greg' has sussed it with the 'Tracking'

So I am going to check the Tyres and put up a Photo if I notice anything wrong.

Hi Greg

The Squeal is coming from the Front Tyres.

Looks like you were right about the 'Tracking' Take a look at the Tyre Pic and you can see a lot of wear on the inside edge and this was on a nearly new Pirelli.

Finding a good garage who can do the job could be a problem.

Maybe it wouldn't do any harm if I had a go myself? (Trial & Error)

If so what should I do?

http://i1290.photobucket.com/albums/...ps97ed6953.jpg

Hi Pete

I think you might be right!

I had a similar problem with my previous '96.

I replaced the ball joints and upper control arm bushings. Unfortunately, the car only lasted a few months before it was rear ended and scrapped, so I never did find out if I had solved the problem.

I did have to move the shims around on the ball joints because the alignment was off.

The ball joints and control arm bushings will take you a day to do, but it's a job that can be done with relatively little skill.

Front tyre squeal is nothing too much to worry about imo. If anything check the alignment, have you been messing with the brakes at all? Those caliper shims in the front end are essential, finickittity and will knackered your alignment in the blink of an eye.

Hi Vee

That is interesting!

All the ball joints etc have been replaced on mine.

As you may have gathered, I don't have much faith in Garages!

After all when you take your Car for an MOT and then they totally fail to spot that all the Shock Absorber Bushes are missing! that kind of tells you everything that you need to know.

The new Shock Absorber Bushes that I made myself, have totally transformed my Car, way beyond my own expectations.

She used to rattle and bang so much, I thought She was falling to bits but now (apart from the front wheel squeal) She drives as smooth as Silk and handles like a really proper Sports Car.

So as 'Greg' said the squealing was not to do with the Bushes, I am going to make some more, for my other XJS that I am restoring.

While I love the Pirelli's because they have excellent grip, the only downside I've noticed is they do tend to wear on the edges, or in this case the edge.

Just wondering what make of Tyre you are using yourself?

Hi Tyran

I did have a Caliper problem, when one of the pistons got stuck and I lost all the brakes.

So I replaced the pair of them with New Calipers and I did put the Shims back, which as you say are a fiddly job to do, so I may just take a fresh look at them and see if I did something wrong.

Hi OB
Been away a bit so just picked up this post but I think that I have spotted your problem.
There are no such things as slow corners in an XJS ergo your problem is just in your head. Or ears.
Or maybe your front tyre pressures are way too low.

Paul, you definitely SHOULD be worried about your tires!!!
The one in the attached photos had fewer than 5000 miles on it from "new" when I shredded in. Only after that was it discovered that all 4 were TEN YEARS OLD!!

They came with my car and still had rubber whiskers when we took possession.

Everyone should be aware of the number of 'new' old tires making their way to the consumer market. Everyone should find a decoder for the build date of any tire that's being mounted in their car.

ONE MUST NOT DRIVE ON OLD TIRES!!! People have died because of this!
(';')

OB, maybe this is what happened:
Someone in the past did a full alignment on the car while that bushing was in the condition you found it; missing.

After you "replaced" that bushing the true adjustment of the alignment came to light, and it is now Way Off!!

Normally, front alignment isn't a DIY affair as it requires specialized tools, turn tables, leveling gauges and that sort of stuff, none of which is cheap.

Ask around for a reputable shop that your friends like and take your car there for a complete front end tune-up.

If you're reluctant, ask yourself how many tires can you afford to shred in this manner before you bite the bullet and have it done right?
(';')

Maybe you fitted American tyres?
I've seen (heard) them in the movies; even in the desert thay squeal when going round corners.
Don't fret, let the tyres wear in a bit and get rid of all the sticky out bits from the manufacturing process and they will be fine. Mine did exactly the same on the 8 feet of good tarmac between the potholes/ruts/trenches/drains/road kill etc that litter our highways over here.
And check the pressures!

Hi Elinor

I think 'Greg' may have nailed it and as you say, She probably needs to have a full re alignment but I'm taking her off the road at the end of September when the Tax runs out.

To Concentrate on restoring my other XJS 'Cherry Blossom' which would and should have been finished by now!

Except we keep getting unusually hot and sunny weather, for this time of the year, which just makes me want to go out 'Because.....'

Hi Steve

I was wondering what happened to you, not heard from you lately, I actually quite like the sound but its going to cost me a fortune in New Tyres!

Hi Steve

They are Pirelli's and they are not wearing in, they are wearing out!

Why is that 'Christmas Tree Smiley' not Cheering me up! it's Still only September don't yer know! :icon_tree:

OB
DIY alignment just about impossible. Ask around and find a garage with a laser tracker with the reputation of knowing how to use it. Then ask them to set it up at 1/4° toe IN. The track rods on BOTH sides of the rack need to be independently adjusted, rack always centred, to give the correct reading on each tyre. Not all operatives understand this, and some just wind one side in or out to give the required overall toe - leaving the rack uncentred and the steering arm angles each side different = DISASTER.

Centering the rack is the most important thing. My car has been fitted with the later ZF rack which has a rubber bung in the rack, just to the left of the steering connection, hiding a hole into which a 4mm rod goes, and goes in further when the rack is centred. If your rack is an earlier type, I do not know if it has this feature or not. If not, usually the laser trackers turn from one full lock to the other and calculate the central position from those two extremes.

Overall, I agree with Steve's analysis, but an alignment is a good idea in any circs. You can forget about all the BS (I bravely disagree with the Great Palm over this) about special tools, suspension height setting etc etc, never done it, never needed to, never met anyone who has or any garage that does. The only thing you can set easily on an XJS is the toe. Camber is a major job and cannot be changed easily, so no need to worry about that at the garage.

As I mentioned before, if the thing rolls straight and tracks well on long corners without constant sterring corrections, the alignment is not far out. As for the tyre wear, if they are brand new, not old brand new, tyres then the track only needs to be 1/2° out, I have found, to produce this sort of wear.

Greg

I drive on Comtinentals. Extreme DWS or something like that.

Before that I had Bridgestones and I loved them, unfortunately they didn't last...I don't think I got to 30,000 miles on them.

Anyways, I was referring to your Upper Control Arm bushings. If you did the ball joints, I'm kinda stunned you didn't get those either. With the upper ball joint off, I can't image how it would add 30 minutes to the job.

Failing bushings can make it hard for an alignment to be consistent. Not saying it's your problem, but they're not expensive and it's a straightforward project to tackle.