Hey, I have an '84 XJS with a Chevy V8 motor, here in Oklahoma City. The drivers side tire wore out unevenly, with the inner half going bald much faster then normal. My question is, how can I get a reliable diagnosis of the problem? A major tire store said it needs outer tie rod ends and alignment, but a local Jag mechanic said it needs front lower control arms bushings. The tire shop wants $589, and the Jag shop wants $988! Obviously
one of them is misdiagnosing the problem, right? Is it a better strategy to do a full rebuild of the front end? All new parts? How much would that cost?

 

It probably needs both, certainly a suspension rebuild must be followed by an alighnment.
Can you post a photo of the bottom wishbone suspension bushes? If they have gone home it is pretty easy to spot the squeezed-out rubber bits.
If you have covered space, and enjoy this sort of thing, a suspension rebuild is not difficult to do yourself. The actual bits (top and bottom wishbone bushes, top and bottom ball joints, tie rod ends) will cost about 200 USD tops.

If the camber is off - and this can only happen if the subframe is bent - that is trickier to adjust, but quite possible even so. Take a look at this thread which shows what is involved (ignore the subframe change, that will not be needed!).
https://www.jaguarforums.com/forum/x...-c8673-242611/

The first thing to do, before spending any money on bits, is go to an alignment place and get them to give you the data, not try to chnage anything, just get a baseline on where the camber, castor and toe actually are, then post with those details here.

 

Front lower control arm bushings for $988 is the steal of a lifetime. They are an absolute pig to do.

 

But how do I know which one of the mechanics is giving me a proper solution? Don't they contradict each other?

 

Not necessarily. The toe setting could be off, and the lower wishbone bushes could be worn, which causes the toe to change as you drive.

 

I was quoted 8 hours labor for the front lower control arm bushings, it takes that long?

 

8 hours is a bare minimum. The lower fulcrum shaft rusts into place and has to be beaten out. On the V12 the bolt can’t come out with the subframe on the car because the engine is in the way. (Your Chevy might differ). It’s an awful awful job. Probably the hardest thing to do on the car. I’d rather do rear rotors abs calipers.

 

Just to show you how confusing things can be.

When I first bought my first XJS, that was the problem I inherited.

UPPER control arm bushings solved the problem. The shims needed to be corrected as well, so that might have been the problem too. You see, correcting the shims isn’t something most garages will fix.

Its not difficult to do (I don’t have a garage, did it in my driveway on a nice day) and you will get to know you’re car a lot better.

Let’s start with an alignment check. That will help us go in the right direction. If you’re lucky, you have a shop that will charge extra for unlimited alignments. You’ll likely make money on that offer.

 

Thanks everyone for your wisdom!

 

Since you didnt say, Do you have the inclination or ability to have a look? Sometimes a bad bushing in any location can be very easy to see (sometimes not). And tie rods can tested pretty easily too. Then at least you would have some amount of peace of mind. Just throwing it out there.... Good luck.

 

OK, reality, age is against ALL the rubber components of that car.

Wheel align outfits DO NOT want to touch it, they have no one there that has a clue about these cars, which is fair enough.
Jag dealers, likewise.
Independent Jag workshops, best bet.

One of mine did that, out of the blue, and the LH lower inner, rear bush, the one hidden by the rack, went home. 300kms from civilisation, so drove it home, and screwed that tyre.

My suggestion would be:

Lower inner bushes = 4.
Upper inner bushes =4
Cradle "V" mounts =2
Cradle front round mounts =2
Steering rack mounts = Poly Kit.
Engine mounts = 2.
Lower inner pins =2.
Ball Joints = 4

Do it all, do it properly, repeat in 30 years time.

Tie rod ends and inner rack ends, not a known issue in the big scheme of the car, the rubber stuff, as said, waaaaay past its use by date about 10 years ago.

When I picked up my X300 XJR, some 1600kms away, it needed front arm bushes etc when I arrived home, I knew this prior to the trip. $1500 all new rubber, 4 ball joints, alignment, drive in drive out. NOT worth me getting hands on with it.10 years now, still sweet as.

 

FORGOT, it happens a lot now.

Read and print that sticky I wrote on wheel alignment at the top of this section. Take it with you, and demand they read and understand what is needed.

It the alignment is NOT done to spec, as in procedure, those lower inner bushes will fail withing 12 months, fact.

I think??? I have a PDF on DIY those bushes, but cyber space is hiding it at the moment, I will drink beer and look later.

ALSO

Slip into the XJ6/12 Series 1,2,3 Section, one up from this one.
LnrB is doing her front cradle rebuild as I type. She has an excellent step by step. Same cradle etc as your car, and she also has a Chev in hers.

 

I think so. I agree with Grant. Do it all and forget about for a couple decades.

Upper control arm bushings are easier than most cars. Upper and lower ball joints easier (or at least no worse) than most cars. Outer tie rod ends no different than most cars. If you're paying to replace lower control arm bushings you might as well have 'em do all the rest if your budget allows.

The shop who quoted 8 hours for the lower bushings will probably end up regretting it. They probably don't know what they're getting into.

If I were quoting the job I'd go with 16 hours for the lower bushings (misery and aggravation surcharge) and toss in the labor for upper bushings, ball joints, and tie rods in for free....as it takes almost no time to replace those things when you have the suspension torn down for the lower bushings.

Cheers
DD

 

Most of the suspension items can be done by you, because they require no special tools.

If you’re interested in doing some of this yourself, please let us know. We can recommend parts and help you prepare. (Suspension rubber should almost always be OEM, ball joints are Lemforder)

The only item missing from the list are sway bar links. The rubber on them are probably gone. These are also rather easy to replace, especially when you’re already in there doing ball joints and upper control arms.

 

If your getting the lower inner bushes replaced, best bet is to have the shop just drop the front subframe/steering rack in its entirety & replace all the perishables, IMO.
My subframe rusted above the spring perches so I had to replace it & renewed all joints/bushes at the same time. I can't imagine how awful it would have been trying to do them all with the subframe still on the car!

 

AMEN!! Much easier to do out of the car, and you have to drop the rear of the subframe anyway on the V12 to get the lower bushing pin out. Bite the bullet and do every bushing, mount, and joint at once. I did it on the floor of my garage, and it was nice to be able to get to everything easily. Also gave me an opportunity to fix and replace lower gaskets and seals on the engine. The only special tools I had to get was an engine support cross bar (Harbor Freight), and threaded rods to remove the springs.
Removing the springs and the lower bushing pins were the only real hard part. And the springs weren't that hard, just time consuming.
Fortunately, my lower pins had zero rust and came right out.

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I replaced the lowers on my XJS (and my Series III) without lowering the subframe. I recall that the steering rack is the only thing preventing the pins from coming out. I just dropped the rack.

Cheers
DD

 

I don't know how. Clear interference without dropping the back of the subframe on the XJS. The ROM says to remove the whole subframe.

 

I have been wearing Firestone/Tires Plus out on Lifetime alignments for 14 years now.

 

The Jag mechanic replaced the front lower control arm bushings for me. The car handles beautifully now! Thanks for all of the advice guys!