Lincoln/Jaguar fun with vibrations

[artie ziff]

Ok here is my problem. The car in question is a 2002 Jaguar S type which shares the exact same suspension as a Lincoln LS. I own both a LS and the S Type so I have lots of practice working on both of them. The car has a shimmy in the steering wheel. Starts at 40 mph as a slow side to side wobble of the steering wheel and increases to a sharp vibration the faster you go. It never really disappears no matter how fast you go. First and most obvious thought would be wheel balance or rim. The rims have been verified straight on a road force machine and the tires are brand new and have been balanced multiple times. The funny thing is that the cars feels real tight and firm. It does not wander and does not clunk or grind.

Here is what has been replaced. All the work was done by me so I know it was done right and the parts are of good quality.

Both front wheel bearings/hubs
Both front lower ball joints
Both outer tie rod ends
Both front rotors
Both front upper control arms and ball joints
Alignment done twice. Cars is with in spec for all tolerances.
I put two different sets of wheel on the car and still have the problem so it does not appear to be wheel/tire related

All that leaves is the steering rack / inner tie rods, struts, and lower control arms. There is not anything else to replace. The lower control arms seem to have some play in them. The front bushings look cracked and may even be missing some material. I don't mind changing the rack which will eliminate two suspects, but I feel like I am guessing at this point. Struts don't seem like they would cause this problem. Drove it down perfectly smooth new asphalt road and still had the vibration so road surface does not seem to have much to do with it.

I am stuck at this point. Any body have any experience, suggestion or resolution to this problem? A search of the forum did not really seem to dig up anything.

Thanks

 

[2000sport]

I am having the exact same problem, have replaced the same items, with the same result...

Any input would be great.

I'm really leaning towards the inner tie rods.

OP, does your steering have a slight clunk when stopped going from right to left (and vice-versa) with the steering wheel?

The steering is the only bit that feels loose on the entire car. and because of this, I can feel the vibrations in the pedals as well.

So frustrating!

 

[Mechanicboy]

I don't mean to sound like an a$$ hole but are either of you overweight? If you are then have the car aligned with your approximate weight in the drivers seat.

EDIT: also, to be clear you are both using 4 wheel alignments right?

 

[2000sport]

At 5'7 182lbs i doubt my weight is the issue.

I have had four 4 wheel alignments done over the past 3 months trying to figure this out.

I did find a TSB regarding the intermediate shaft and im going to look into that first.

Back when the motor was put in last october, the shop failed to put the set screw in the intermediate (steering) shaft after putting the car back together and I had a huge dead zone on center.

I'm thinking the steering shaft is having some play in it, and it's vibrations are being magnified as input to the variable power steering system, causing the steering wheel shake.

 

[HRLNKN]

Does it kind of clunk if you hit a bump or pothole? And if so, does it sort of clear up when you make a turn?

 

[artie ziff]

I don't have a dead spot in the center of the wheel. Every once and a while when backing up with the wheel cut hard to the right it will make a small pop. The alignment was a 4 wheel alignment and was done someone in the business for many years. Right rear was out half a degree everything else was perfect.

I am 6"8 and 250 pounds and have been that way since the car was new so I don't imagine that would be a problem.

No clunks going over bumps. At slower speeds the vibration does seem to still be there when turning.

It has to be a wear item. I have put 90k on the car with no problems and now this vibration appears. I don't mind changing the rack which will also change the inner tie rods. I have already done it in the LS so it should go quick. All the symptoms keep leading me back to the rack.

 

[HRLNKN]

Yeah, your probably right. I'd check the end link bushings anyway, if you haven't already. Cheaper than replacing the rack.

 

[tireman]

tires

many people who have out of round and/or separations in the internal tire structure have the same problems as you. You can balance them until the sun stops shining, but once moving you will get the vibration. I inspect tires for a living and find many with tons of weights trying to solve the shimmy problem. Try listening closely to the tires as you drive down the road, any swish, swish, swish noises or thumping, if so then you got a tire problem. Then there are times when the tire and vehicle designs create their very own vibrations. A different size and tread design can make all the difference.

 

[dreigen]

I have had this problem and found out it was a bad yoke spring in the steering rack assembly. The TSB about this issue is TSB: 01-15-1.

 

[rwurst918]

I have had this problem and found out it was a bad yoke spring in the steering rack assembly. The TSB about this issue is TSB: 01-15-1.

This actually makes sense even though I have an 04 that does this. Only problem is I cant find where this yoke goes or how to install it.

 

[2000LS6]

a bad drive shaft center bearing can cause vibration. it will be a high frequency vibration when compared to a tire vibration and, in general, should not be felt in steering wheel.

a competent shop will have vibration analysis equipment which is mounted on the car. this equipment helps pinpoint the location and cause on the vibration.

i would think a bad steering rack would be evident when grabbing the tire a pulling left and right when the car is on a lift.

 

[Fla02LS]

many people who have out of round and/or separations in the internal tire structure have the same problems as you. You can balance them until the sun stops shining, but once moving you will get the vibration. I inspect tires for a living and find many with tons of weights trying to solve the shimmy problem. Try listening closely to the tires as you drive down the road, any swish, swish, swish noises or thumping, if so then you got a tire problem. Then there are times when the tire and vehicle designs create their very own vibrations. A different size and tread design can make all the difference.

I'm going with this answer. If any recall i had some horrible issues with some Bridgestones, had five of six tires separate, and i had the exact same vibration. Irritated me forever. After installing four new tires.... vibration gone.