Front end shimmy when > 60mph and slightly turn wheel to right

[BrettB]

1990 XJ 4.0 4x4 NP231 >241,000 miles

I have had a problem where when I am going straight faster than 60 MPH and I have to slightly turn the steering wheel to the right. The front end will start to shake violently and get out of control. I have to slow down and turn the wheel back to the left to gain control back.

This has been happening on a smaller level for a couple of months and was more of an annoyance than problem. Recently I have had new front brake pads put on and a front-end alignment and it got much worse afterwards.

Everything is stock. The shocks and steering stabilizer are three years old. Could it be caused by the shocks?

I had the tires rebalanced about a month ago (before it got real bad) and it did not seem to make a difference. The track bar does not seem to be loose.

Any suggestions on what to check?

Thanks

 

[BrettB]

I got underneath last night and could not find anything loose. I put the front end in the air had no play when grabbing the wheels and trying to move them.

Tonight I am going to rotate the tires to see if it makes any difference. Next step is new shocks.

 

[martin]

BrettB,

If I was to guess I would say you need new front hubs for your XJ. If you have not replaced then then you are way over due.

The biggest pain is to get the old hub off the kuckle. There is a write up on www.madxj.com about chaninge axle shaft u-joints and has good pictures on removal of the hubs.

When you make your turn you load one bearing more than the other and evidently there is something wrong with the race or the rollers.

The hubs are purchases as an assembly, and are prelubed.

I changed mine out last year and ended up paying the local shop to do the work since I could not get hubs out of the knuckle.

While you are chaning the hubs it smart money to also replace the axle shaft U-joints, I am not talking drive shaft u-joints. You can buy new u-joints or do the upgrade talked about on madxj. I just changed my U-joints and did not upgrade to the 5-290 U-joint.

The problem with this repair is the "while you're at its..." kicks in. Do you do an axle service, do you change axle seals, that stuff.

I got my hubs at hagars4wd, they had the best price at the time. Find the Jeep part number for the hub, then do a yahoo search, buy for the place that has the best price.

If your shocks are old I would change them first, they are easier to do. I really like the monroe reflex. I put on the blue monroes 3 years ago and that when I found out I had warped rotors. With the old shocks the steering wheel would move violently but not pulse in the pedal. After the new shocks the wheel would still moved much less but now I had a pulse in the brake pedal.

HTH

Martin

 

[Matthew Currie]

Another possibility, since it appears to happen when you turn only, is that one of the axle u-joints is stiffening up. Try jacking it up again, and cock a wheel a little, and see if it starts to fight when you turn it.

 

[HossHoffer]

You can just have new bearings pressed into the hubs at any good machine shop. Save a little scratch.

 

[BrettB]

I was testing it out yesterday and I can feel when it is about to start wobbling. At this moment I can slow down. But if I hit anything kind of bump it goes out of control. What is weird is that I don't really feel it in the steering wheel.

I got three of the shocks replaced last night before a thunderstorm force me inside.

Reading the other posts jogged my memory. The last couple of times I engaged the four wheel drive I can hear a clattering sound when I press the accelerator and turn to the right if the surface is not very slippery. Sounds I am going to have to redo the bearings and axle u-joints.

 

[BrettB]

Just put the last shock on and took it for a test drive. I am not able to make the wobbling happen anymore but it does do it some. The difference is that it doesn't shake the whole vehicle and I am able to get it to stop easier.

I plan to get the tires balanced on Monday to see if that is the initial reason behind the shake.

Thanks for the suggestions.