DIY wheel alignment a success 420G

Saloons
1

After an overhaul of my IFS and steering components, I thought it wise to get a pro alignment shop to set toe-in up, (and cause they give you a printout of camber, castor and toe)…wrong!

I had to give them the specs myself, out of FSM, and INSIST they used the steering box centralisation keyway (which is whats its there for)…NOT the steering wheel (which I told them had been off its splines unknown times), they reset toe-in and give me a printout which shows everything is near enough to spec
(laser alignment equipment)

So my steering wheel is then ~3 splines off centre when maintaining straight ahead driving, even with steering box centralised and wheels dead ahead at ground, stopped

I decide to use the method described in FSM, using a 5metre channel section of aluminium as a straight edge…I also use calipers to check equal tie rod length, and a 600mm steel rule

it is immediately apparent that instead of toe-in, I have 10mm gap at rear of DS front tyre,meaning toe-out
and 23mm!! of gap on PS

the procedure is there should be a 16mm gap at front of REAR tyre, when straight edge touches front tyre both edges

ajust till I have this gap, but found tie-rods to be unequal length, so compromised a little for the moment, but it is MUCH better than before, steering wheel is now centralised, and slight to-in on each wheel

dont know how come the paid-for laser printout job was so badly out, but this is to recommend ye old skool ways to those who want to set up, or check the alignment

2

It’s not exactly rocket science, is it?

Does your G have steel or wire wheels? Some of the camber gauges are constructed so that they haven’t got enough “throat” to get around the K/O. It’s not a big deal… you just need to make or buy some equal length spacers to get more space between the rim and the gauge.

You can buy all the kit you want, but if you don’t calibrate it, or understand how it works more than putting a new roll of paper in and pushing the button…

Was the guy operating the machine old enough to have learned geometry and trig, or did they learn math via Excel at trade school?

There is a generational difference: whereas an older guy might measure twice, scratch his head and mutter “Can’t be!”, the younger might just be listening for the computer to beep, the vehicle to go “Bang!”, or the CC reader to display “Payment complete”.

Did you ask for your money back?

3

He was just a young sleeve-tattooed fella, and he was battling to get the rear wheel devices fitted because they have the S3 XJ SS trim fitted to the steel wheels, but if he wasnt certain he should have told me to go away and do it. Mirrors and lasers are attached to each rim

his older colleague had worked as a Jaguar mechanic for several years, but had never worked upon a 420G, and new nothing of the steering centralisation procedure

I wont be asking for my money, as the proprietor is a mate who has looked after me for years.

can only assume the fitment of rear mirror equipment caused the issue

next up is the castor, as when I assembled the IFS, I put all the shims the same as they came out, but they were different each side, clearly I cant trust the shop mechanics to get it right at $100ph

4

I take it you mean camber.

If possible it pays to check camber before you take the IRS out. Then while disassembling mic the discs, camber shims, hub spacer, and the end float shims under the output shaft flanges and record that info. Once you’ve dialed the diff in, changed the hub spacer, and mic’ed the new discs you can do the arithmetic to end up with the right camber.

You can also set the IRS on the bench with the tie plate dead level and do the camber on the bench. If your rear chassis arms aren’t bent then the tie plate/bottom of the diff housing is level when the IRS is in the car.

I think this is the case for all Jag IRS’s, but I’m not certain. It stands to reason: the IRS was originally assembled as a unit ready to fit, and they would probably have used a jig which fit all IRS variants. Checking that a jig datum is dead level is easier than checking an angle.

5

my apologies, went back and edited one letter, meant IFS Castor of course, hopefully doesnt negate the value of yr post

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