Death "bounce" on stock XJ

I'm looking at a clean 93 Country for one of the kids. I know the guy who has it, and he is very good about maintenance, it's been his primary driver.

It's a 4.0 auto with a NP231. About 175,000 on the odometer. Stock suspension but, it has one major problem - a death "bounce" that occurs around 45 mph that came up suddenly. It's not death "wobble", one of the front tires just starts bouncing up and down

The shocks are Monroe Sensa-tracks about 30K old, he rotated the tires and had it realigned with no improvement. He took it into a local shop which test drove it, inspected it and said there was some front-end wear but not enough to cause the problem or warrant spending the money to rebuild the front-end. They told him that his tires (a cheap off-brand and fairly old) have enough tread left to pass inspection, but they need to be replaced and that's where the problem is coming from. He's convinced the shocks have gone bad. . . Think this problem is as simple as tires?

The only other issue this XJ has is it uses about 1/2 qt of oil per tank of gas - no leaks, no blow-by. . . Emissions issues?

Probably the tires - could be the shocks. I've had this problem on several old vehicles (not Jeeps) that had very worn tires. To be sure, you could balance them and it might help but you would have to do that when replacing the tires anyway.

If I were looking to buy this Jeep, friend or not, I would tell him to replace the tires and fix the bounce before I would even consider buying it for my daughter. If he thinks it the Shocks - have him do those first but I still would not consider the purchase if the bounce is not fixed. Heck, you may get lucky and get a new set of tires and shocks on it before you even have to drop a penny on it.

I would have a mechanic put it on the lift and check the front end good. Hopefully it is just a blown shock or the crappy tires. In regards to the oil issue, I woud guess the engine is getting tired and burning it off, but someone else most likely knows better on this than me. good luck

I'm willing to bet that the front tires are out of round (broken belt(s))
Thats like trying to drive a car with eggs as wheels.

peeweexj said:

I'm willing to bet that the front tires are out of round (broken belt(s))

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I called and talked to the shop he took it into. . . Turns out the guy who looked at it, is a friend I wheel with. He says same thing, "broken belts". . . and it has been up on the lift - there's nothing wrong with the front-end.

Previous owner has spent a ton on it in the last year (brakes, steering, water pump, fuel pump, oil seals, tranny service) and just wants something newer. . .

Sooo. . . looks like I may be 4 XJ family soon . . .

peeweexj said:

I'm willing to bet that the front tires are out of round (broken belt(s))

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I tend to agree with this also. I had a van with a broken belt on a rear and the back end would hop at cetain speeds. When I took the tires off to try rotating them, I noticed the tread looked a little crooked on one tire. Since yours is on the front, maybe you can just jack up the front and spin the tire and watch the tread. If you see the lines in the tread pattern shift at one point that's probably a good indication of a belt problem. In my case, after I put my glasses on and took a closer look, I actually saw a thread of steel belt poking through. And these tires still had plenty of life left in them, just passed inspection in fact. But, they were also the cheapest ones offered at the time at Strauss.

3XJFamily said:

Think this problem is as simple as tires?

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Yes

sounds like tires to me as well. most likly a broken belt.

yeah dame thing with my xj replaced tires everery is good now

peeweexj said:

I'm willing to bet that the front tires are out of round (broken belt(s))

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My thoughts exactly, especially considering they're cheap off-brand tires, who knows what kind of crap they are.