Understanding alignment figures on xj6 series 3

Can anyone help me understand these figures
I am worried most about rear Toe
-1.7 left + 1.6 right
Does this suggest something bent or damaged or could it be worn bushes?

Camber angle is most important, who ever did the wheel alignment check would have or at least should have checked all suspension components, if they didn’t report bushing problems then it should be ok & by those readings it appears ok, incorrect amber angle causing wear on the inner edge could be mistaken for a toe problem, bushing wear would give a bad camber reading…so how are tires wearing?

Hi Graham and welcome,

First of all, tha shop did nothing but adjust front Toe.
Both front Camber and Caster need attention.

As for the rear, Camber is ok, but Toe is indeed not very good.
What it means is that your left wheel is pointing out and the right wheel is pointing in, so the Thrust Angle is not parallel to the car, pulling the car in one direction when you accelerate, and in the opposite direction when you brake.
It is not very much, you could compensate this by tweaking the front and the car will drive 90% straight, but will eventually wear the tires unevenly.

As Toe is even on both sides, but in opposite directions, it indicates that either there is a problem with the IRS bushings and the IRS gage is out of alignment, either that the car had a serious accident in the past and the frame is bent, or that the swingarms are bent.
Unfortunately, there is no easy/simple fix for any of the above.
Measure the Track and see if it’s different between left and right.

Having said all that, it is not certain at all that these are the true angles. It all depends on the competence of the alignment shop and on how much the settle the suspension before taking the measurements.
I took mine four times and everytime the measures were different… in the end I did it myself and for the first time the car was driving straight.

Another very important factor is the Ride Height Setting Tools. Did you use them?
As the factory values are given for a specific ride height, measurements without the tools are just approximations, especially for the rear.

What year is your car?
Is the ride height equal on both sides?

The rear toe is not adjustable, Graham, and specs are ‘0’ +/- 0,08 mm - with reference to the car axis/direction of travel. Ie, the rear wheels then travels in the tracks of the front wheels…

The rear wheels are indeed parallel to each other, but not to the axis - the car is ‘crabbing’ sideways. Basically, a steering wheel input is required to make the front wheels parallel to the rear wheels for straight travel. It’s almost imperceptible - but it is there.

Since the fault is symmetric, a possible cause is rear cage misalignment, may be worn cage mounting rubbers? However, other fault cannot be excluded - and it is very important that there is no play in any component related to alignments, like bushes, joints, bearings etc. And as Tom says; a reputable shop will not carry out adjustments if there are play…

All other adjustments are adjustable, but camber angles are particularly sensitive to ride height/ symmetry side to side. As Aristides says; using setting tools ensures such symmetry and ensures greater precision. However, within reason; ride height if even, will give adequate precision for reasonable results…

And welcome on board…

xj6 85 Sov Europe (UK/NZ)

Thank you Aristides for your comprehensive reply.
My car is 1986. No indication of an accident, it all looks very original.
I don’t know about ride height, and certainly this wasn’t checked.
I too am on my third alignment shop, bad pulling to one side ended up with me changing all tyres.
Tha car now feels much better but too soon to know about the wear.
The wet tyre tracks don’t show serious crabbing.
Should I just drive it and stop worrying?

Thank you for the reply.
I am in New Zealand, and even though I have travelled the length of the country it is hard to find a good classic car mechanic and standards here are very low in the industry.
Can you suggest how I check and adjust ride height?
Thanks again

Hi Tom
I have just changed all tyres to try and solve steering problem so I can’t gauge yet.
The old tyres were unbranded, very old and indicated that the car had stood still for a very long time with flat spots but tread was very good so difficult to tell.
This is a complicated topic!
Thank you for your reply

What the shop did was basically straighten your steering wheel, according to the measurements it must have been of-center.
Your front Camber is ok, but Caster being uneven and the Thrust Angle not straight, the car will need a constant input from the steering wheel to go straight causing uneven tire ware, mostly at the outer edges in the front.
It’s not much, but keep a close eye at your new tires.

You really need a workshop manual, Graham…

At the front you measure the ride height from the centre of the outer headlamps to ground. Press front end down on the bumper at the headlights - then lift and slowly release. Correct height is 611m (24 5/8") - even on both sides is important.

The setting tool mentioned earlier sets this height, but only for ‘proper’ suspension alignment - not to be used when checking ride height, of course. The front can be adjusted by adding or removing packing rings - which requires removing the front springs. And springs may have sagged to an extent that they need replacement…

However, within reason and with even heights on both sides, doesn’t really affect car steering and roadholding - and has marginal effects on alignment…

At the rear; the preparatory procedure involves rolling the car three length back or forth - and ride height should be measured with full tanks or similar weight in the boot.

Height is measured from the tie plate to ground, both sides; 189 +/- 6,4 mm (7,45 +/- 1/4"). The rear height is not adjustable; ‘too low’ generally means sagging springs which must be changed to restore ride height,…

However, again ‘within reason’ and even, you may live with it as is; it affects camber, but not toe. Which is likely the main reason for your ‘directional’ problem. The adjustment made by the shop likely reset an offset done by a PO - but no front end alignment can counter your rear toe fault. Steering inputs will be required to keep the car straight…

xj6 85 Sov Europe (UK/NZ)