I recently had a new set of tires installed on my Dayton wires along with a good balance and alignment of the wheels in the hope that that would address a marked "shake" when driving over 65 mph. I also had the wheel bearing repacked on the rear passenger side.

All that the new tires, balance, and alignment have a achieved is to move the speed where the shake starts up to about 70 mph.

Where should I look now to find the source of the "shake"?

 

How old are your control arm bushings...

 

That's what I would look at...

 

As far as I can tell, they have never been replaced (Unless they are the same as "front suspension subframe mounts" - those were replaced in 2007).

Are there any other bushings I should replace while I'm at it?

 

I'd replace the upper and lower ball joints and tie rods while you're in there.

After you're all said an done, you'll have to get the car aligned again.

If you have a full day to spend, you should be able to handle this yourself.

 

Rods, ball joints and don't forget those nasty little shims in between the front callipers / arm - they quickly knacker alignment if they have walked.

 

As well as the above, a new set of front shock absorbers would be a good idea. New tyres are often more resistant and less supple, and they find out weakened shockers as a result.

Greg

 

Make sure you buy Lemforder bushings and ball joints. Apparently it's OEM, but you'll pay somewhere between dealer and low end aftermarket for them.

I'm not sure the Lemforder tie rods are worth it though. I think I bought those in the past and the Moog looked every bit as good at half the price.

 

Well all of the above are certainly areas that could cause vibration issues and are parts that will wear out and need to be replaced at some point. But they may not be what is causing your problem.

Before undertaking (and the cost of) all that work, you might want to do a little investigating. With the car up on a ramp, carefully examine all the bushings, ball joints etc. Quite often it is obvious when they are worn. After your visual inspection grab each wheel at the 12 and 6 o'clock positions and give them a vigorous push and pull top and bottom and together. Any excessive movement may indicate your problem. Also do this at the 3 and 9 o'clock positions.

Next, using a pry bar, see if you can move any of the joints/bushings.

Again don't be surprised, even if you find bushings that need replacing, that it does not solve your problem.

Another test if you have the car in the air is to remove the rear wheels and run it up to speed and see if the vibration occurs. If it does then the front suspension will not be the issue.

If the vibration is still there, then you can disconnect the half shafts from the diff and try again. If the vibration is still there then you will have eliminated the halfshaft u-joints and the rear wheel bearings from the equation.

Finally you can disconnect the front of the propshaft from the gearbox and try again. If the problem disappears the the issue could be the propshaft u-joints, propshaft balance or the diff itself. The only way to check these would be to remove the propshaft (already halfway there ) and test the joints for any stiffness. You would have to take the shaft to a shop to rebalance it. If the propshaft is fine then measure the run out of the pinion shaft of the diff and measure the end float of the output shafts. Excessive movement will mean a re-build or a new diff.

If disconnecting the propshaft did not make the vibration go away then perhaps look at the engine mounts but I think this is unlikely.

You can do all of this in a morning without any cost if doing it yourself, just be very careful running the car while it's up in the air. If you cannot keep the car rock solid stable, DON"T do it!!.

The reason I mention all this, is that I just went through this procedure with my XJ6 after being confounded with a vibration issue

 

I would take the car back to the tire dealer to recheck balalnce. The smartest tools in the shed don't work at tire dealers. Easy to add the wrong wheel weights also. Wire wheels are a PITA! But always look great!

 

I have had the alignment checked as well as the wheel bearings all checked out ok.

So here's my plan I'm going to have my mechanic replace the following.

Ball Joint Upper & Lower (Lemforder)
Tie Rod Ends Outer (Lemforder)
Control Arm Bushings Rubber
Steering Rack Mount Bushings Poly
Bushings on the top of the front shocks Rubber

I'll wait to see if I need/can afford new Bilstien shocks up front.