The car has had a shimmy at highway speeds since I bought it in Aug, so I took it in for it's first alignment a couple of weeks ago. After he was finished the Jag tech said the front suspension camber was still out by .38 degrees on the right and .26 on the left so it would need camber bolts on both lower rear control arms. After the bolts were put in, the camber was still out by .18 on the right and .07 on the left, though the shimmy has been reduced to a decent level on the highway.

His suggestion to try to further help the camber issue was to replace both lower control arm bushings on both sides, since they look a little worn. They quoted me $200 a side to do the job, and I went home.

At the time I thought I understood what he was talking about, but now I'm not sure I understand the relationship between replacing the lower control arm bushings to help camber issues. Any thoughts? Does it sound like the proper approach?

 

A few years ago I replaced the lower control at the rt front corner of my 05 XJ.. Part of the process was to carefully mark the position of the camber adjust bolts, which are eccentric, before removing any components. That's so you can get the alignment back in the ball park after the work and before driving in for alignment.
At that time I noticed that adjusting this bolt acted on the lower control arm. It therefore follows that changing the position of the control arm has an effect similar to adjusting the camber bolt. A worn control arm bush, they are quite large, changes the position/stability of the camber adjustment.
I'm assuming the XK suspension set up is similar to an XJ. I think your mechanic is on to something. One could argue why he didn't go for the control arms first but in fact both adj bolt and control arm bushings are high wear items.

 

Yes, great point! I was wondering how the new bushing would affect the eccentric adjustment of the bolt. That could be it. I'm thinking I'll try it on the side that's farthest out of alignment, and see how far back it brings it. Thanks!

 

Don't forget the spring pads at the top of the front shocks. Take a close look if you haven't already ruled that out

This is something I've been needing to get done. As these squish down over the years and miles it allows the front to sag putting the ride height "deeper" into the suspension travel. This by geometry of the suspension will increase the camber. I can see it just standing next to my car.

 

Worn lower bushings would allow the bottom of your tire to extend further out; hence increase the camber. Your mechanic's logic is that a new bushing would pull the bottom of the tire more upright and decrease negative camber.

IMO most the negative camber you are seeing is caused by worn springs.

 

I showed him the shock mounts, they look pretty healthy. One is a little off center, but it's on the least affected side. When I get new front shocks I'll definatly get new mounts, but that's a ways off.

I hope my springs aren't gone already, only have 83K on them. I'm going to have the lower bushings done on the right side. That may get rid of the problem.

 

new shock mounts and shocks will bring your ride height up and improve your camber dramatically, I gained 0.5 inches and brought my camber from out of spec into the proper range. I've found its allowing me more miles on my front tires too, probably 50% longer life due to more even distribution of the weight. True that springs will slowly weaken, but not reach a point that is unsafe before you get many more miles and years on the car.

 

Do you think I should skip the bushings and go right to the shocks and mounts?

 

Before you do a bunch of suspension work for a shimmy, have you had a Roadforce balance?

 

I know we've been through this before, but I don't see how a shock absorber could change the ride height. It simply dampens the movement of the springs. It doesn't put any upward pressure on the suspension. Shock MOUNTS on the other hand can definitely affect ride height. If that rubbery stuff breaks down the metal bits on the mount get closer together and that would lower the height.

 

shocks cannot raise ride height. Spring cushions can and do. But not shocks per se.

 

Yes, and on both sets of wheels. The shimmy with the 17's is much less than with the 18's, probably due to the different profile of the tires.

I was thinking that too, my focus is on the shock mounts, especially since both studs are off center in the mounts. With 83K on the car though, I'm figuring that may as well change out the shocks if we're changing the mounts.

By spring cushions do you mean where the springs attach to the outer part of the shock mount frame?

 

When you say shimmy, do you mean almost like scuttle shake, a bit like the convertibles suffer from?

The amount your camber is out would not necessarily cause this issue entirely, in my experience when a coupe suffers from shake/shimmy the V mounts are gone on the front suspension bed, it is these that hold your engine and steering/front suspension to the main tub of the car, easy to check

This is what happens to them and it is very common

 

Yes I mean the rubber biscuit on top of the spring perch... the uppermost rubber on the spring/shock assy. It dries out and crumbles, but it is difficult to observe because of its location under the shock tower and its cap.

The front suspension rubber on these cars is notoriously poor. Mine was shot at 53k. Expecially the upper A arm bushings. A long bolt runs through the front and rear A-arm at the inside subassy pickup points. These bushings oval out and cause vibrations, etc. Check them out first. There are a couple of good writeups to search, so I will not explain the complete task.

The metal parts, tie rod ends, ball joints, etc., seemed to wear much better; although realtive to the poor rubber, it doesnt say much. Also, you can buy and press out/in lower shock rubber. It is a pain and sometimes guys simply replace the whole shock assy. For $90 each, the Bilsteins are a pretty good bargin. But remember, the shocks will not be the source of your shimmy... but poor ones, will allow more of the shimmy to be felt.

On mine, I did it piecemeal, although in hindsight, I should have just bought the entire kit and done it once. The car was apart three or four times, and I still have to do the sway bar bushing. I do mine own work, so its not a matter of money for labor... just that it got to be tiresome pulling jacking up the front and pulling off the wheels.

PS. In my vert, a '97, there is always going to be a little shimmy over a washboard road because of cowl shake, especially when the top is down. However, this does not excuse wheel shimmy on a smooth road surface; or when braking hard. g.

 

I think this is a decades-old Jaguar thing.

My observation and opinion is that Jags have much less road noise in the cabin than other comparable cars...or *any* other cars, for that matter. I'm pretty well convinced this is a result of the rubber composition. IMHO it must be softer than what others use.

Cheers
DD

 

An 02 will definitly need upper shock mounts in frt if original. Regardless of mileage. Forget the stud being centered. Look up into the wheel well at the bottom of the mounts. Theyre collasped alittle or alot. It is the number 1 reason for camber being out in front due to dropped ride height and youll yes, need it relaigned. He should know better. Were you at a dealer or......???

 

It's when the steering wheel jiggles up and down at certian speeds. I'll have the V mounts checked when we do the shock mounts. I'll take a copy of those pics with me when I take the car in.

I had an XK8 that had the crumbling upper shock mounts, what's funny is it rode and drove like a dream. My current car has fresh looking mounts, but the studs are both off center and I got a shimmy! Go figure...

Yes, it was at a dealer, and I talked to him today and I've decided I'm going to have him do it all at once. New bilsteen shocks from partsgeek, new upper shock mounts from motorcars, lower shock bushings from brittishparts, and front and rear lower control arm bushings from xks. I'm saving the upper control arms for me later on lol.

Thanks for all the input guys, it was a big help today! I read your posts earlier and would have gotten back sooner but I was researching/ordering parts to get the ball rolling.

 

Hi Skid Mark Sounds as if you are close to getting your "Shimmey" sorted it's been a long road.
My shimmey is at about 70mph the steering wheel goes side to side, under 70 or over 70 all smooth again.Its so slight that I am tempted to leave well alone The 20" wheels probably need balancing but am worried that might make things worse if they don't get it spot on.what do you think?

Thanks Al

 

Hey Skid,

Do let us know how it "shakes out". Sorry, couldn't resist.

 

You need to make sure they check the upper control arms when theyre loose for bad bushings. Or you can check for rust staining. If theres rust staining theyre bad. Otherwise make sure they check for looseness. Personally i would replace them notw while you have it apart because its overlapping labor and youll pay full pop later plus another alignment