I have done alignments on my car, and I bougth the tools to do it. They are magnetic, so stick to the hub. The problem I could see with Greg's method is it is measuring across the rim, rather then the hub. If the wheel is bent or not perfectly true then that bend is measured, rather than the setting of the hub.

I have a ramp type hoist than I ensured was perfectly level when I installed it. I then put 2 pieces of plexiglas with grease inbetween to act as turntables to allow the wheels to move as I adjust them. Then I can get under the car without disturbing it and adjust the tie rods and watch the angle change.

All that being said, setting toe is something of a black art, and very much an iterative process. I can get much more repeatable results setting camber and castor.

 

Wow, way above my pay grade. I do get the idea, sorta.
The math, not so much!!!


I used to check and set toe on my 4x4's with a rule, cord and tacks.
Fat tires on wide wheels.


101 in alignment is equal wheel base, side to side.


Tack a cord on the center of a rear tire Vertical and horizontal. Stretch it to the same point on the front. 0 toe is seen as no cord deflection. Measure the toe by the deflection of the cord.


Old alignment guy's rough and ready. actually a scuff measure.
Smooth and reasonably level patch of concrete. Add water, drive front tires across the we. Tread imprints will remain. Measure center to center. Atad "rough".


Bars and pointers with yard sticks found their way into old racer's stuff.


Way back when, I visited a friend's collision shop. CRA cars were in town to race at the Fair grounds. shop pace was offered. One venerable old scarred Offy powered racer was there. A clearly bent
tubular front axle. The race pit crew and the shop frame man designed a fix. Nestled the straight part against a shop post. Used
a BFH and knocked it straight!!! Tape ruler defined it.


Oddly, it won the main the following day, outrunning far prettier cars.


Carl

 

I bought this set-up three years ago and use it on all my cars, works great. (No affiliation with seller)

http://www.ebay.com/itm/Toe-Plates-M...-/281932528463

 

That looks a great idea, and definitely doable and repeatable at home. The only problem left to solve on an XJS is how to equally accurately measure each wheel's toe, independently from a dead accurate reference point centreline. Unlike on many vehicles, the combined toe can be correct but the alignment still be off individually. Any ideas anyone?
Greg

 

I use that technique with two 1m aluminium rulers, two identical measuring tapes some spacers and a bit of careful balancing with paint pots and weights

The steering wheel on any car should be correctly centred (e.g. the badge or the spokes should look right) when driving straight. If the overall toe is correct but the steering wheel is squint, increase the toe on one side and decrease it by the same amount on the other. It is a bit trial and error, but easy enough if you have a little time.

 

I've tried a couple of the "drive-over" tools in the past and had what seemed to be reasonable results. I love the maths side of Greg's approach but can see the challenges in raising the car, adjusting the rods and then trying to get the car back in exactly the same position.

I admit that I've always thought it's cutting corners to align the wheel by readjusting the track rods. The XJS has the means to centre the rack which should always be the first step, then align the wheel, then adjust the rods. Sadly, there are very few garages out there who even know how to centre an XJS rack.

Depsite all of the great advice, if I change any of the steering or suspension elements, I now take my cars to a reputable garage who use a very expensive Hunter alignment bed. This is a relatively inexpensive way of getting very accurate measurement of my toe-in, caster and camber, front and back. When I refitted my rear cage and rebuilt my front and rear suspension, it was a great way to get my toe-in exactly as I wanted and also find out that my rear axle was exactly in line with the front of the car! (More by luck than judgement, I'm sure.) I do admire those who do it themselves but you do get a very nice colour printout and lots of nice measurements if you use a modern alignment bed.

Paul

 

The main issue I see with using this method is that you are not lining up with the center line of the vehicle. It is possible to set toe so the wheels are not pointed straight ahead.

I use string lines down the side of the car and a metal ruler. This way the wheels are lined up with the center line of the car. Takes longer as you need to center the car in the box.

I have 2 poles that attach to the front and rear with a small chamfer for the fishing line. Remove the hub covers from the wheels and measure from the hub to the line.

 

Paul, who do you use, please?
Greg

 

Greg,

For my XJS, I use MTMC in Tonbridge. The pics below are from my last XJS visit there. The software is very comprehensive. It even advises the operator to use Jaguar tools to tie down front and rear subframes at correct height as part of the procedure. The bed itself is so sensitive that for some cars such as Lambos they've had to close the bay doors, turn off the compressors and all stand still whilst they take the readings! I guess that's what you get if you spend £50,000+ on a Hunter alignment bed!

For my x350, I used ProTyre in Fareham as I was having my rear lower wishbones fitted in that area and my mate had "trained" their technician exactly how to set up an x350 (which is critical to setting wheelbase length correctly first). They use similar software and printouts.

Paul

 

Yes ... that was partie deux of the explanation by the original
author of the method I regurgitated a couple of days ago.

Front toe is always combined because the front wheels have
freedom of movement unlike the rear.

Once the front and rear toe are set, center the steering wheel,
then measure the thrust angle (relative side to side difference
of rear to to center axis of vehicle) by again projecting the
lasers from the front wheels to the target board and marking.

Project the lasers from the rear wheels and again mark on the
target board. The distances from the left front and left rear
marks must be the same as that for the right front and right
rear marks.

If they are not equal, shift the rear toe on each side as
appropriate to move the marks.

There is also another method that involves lining up two laser
pointers so that they point direct at each other forming one
line. Then the vehicle is driven between the two pointers
such that the lasers fire at the hubs. Mount a mirror on
the wheel, measure the offset of the reflected point from
the laser source and do some more maths. This method can
be used to measure both toe and camber.

One shortcut for all the raising/lowering is that a laser mounted
on the wheel being adjusted can be projected at a target and
the change made can be measured before lowering the vehicle.
When done correctly, it will be dead on.

 

While looking around for vintage alignment equipment, which can actually be
very, very good ... I discovered that perfectly serviceable FMC, Bear and Hunter
units in working order can be had for under $1000 locally.

One unit was recently calibrated and had all vehicle updates through 2010.

$750.

Space for setup is the problem

 

It's no good Plums, I need a diagram to get your penultimate post!
Greg