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Unusual Situation


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This happens to be for the "new" 2001 XJ, but could as easily be for any MJ so I'll put it here:

 

Had a lot of clunking under the floorboards when driving over pavement cracks and washboard roads, so I cleverly diagnosed lower control arms. I could grab 'em by hand and move them around, so it seemed like a valid diagnosis. Changed them out with a set of new OEM style (Crown) LCAs over Thanksgiving. There's a lot less clunking, but I'm still getting some, and I can still feel things in the steering shift slightly when I hit a diagonal crack or a bridge joint. I've already replaced the ball joints and tie rod ends, and the track bar is good. Soooo ...

 

Has anyone encountered egged-out holes in the caster adjustment clevises that go in the rear (frame) LCA pockets? I didn't pay as close attention as I probably should have, but I have a sort of fuzzy recollection that the clevis holes seemed elongated -- and they're supposed to be round. Before I take things apart again to replaces the clevises ... is this something that anyone has seen? Does it sound like I'm on the right track?

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I haven't seen it personally with control arms, but it makes sense if your control arms are moving back and forth for a significant period of time, you're likely to see something ovaling out.

It's been a pretty common occurrence for it to happen in all sorts of places on the FSAE cars I've been working on for the last couple months. Mostly it happened with our a-arm bolts, because the half-shafts were broken are re-welded in the pit at last year's competition, so they're not balanced, and that lead to the a-arms wobbling around, which ovaled out their mounts, which made the wobble worse. No one thought anything of it until an a-arm sheared its bolts and the car hit the ground. Hard. We also had issues with the rear tie-rods and the aluminum sprocket.

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Has anyone encountered egged-out holes in the caster adjustment clevises that go in the rear (frame) LCA pockets? I didn't pay as close attention as I probably should have, but I have a sort of fuzzy recollection that the clevis holes seemed elongated -- and they're supposed to be round. Before I take things apart again to replaces the clevises ... is this something that anyone has seen? Does it sound like I'm on the right track?

 

Yes, they are supposed to be round where the two clevis bolts mount through the bucket holes. I really don't see how the rear LCA could move at that point, because the clevis' function in life is to keep pressure on the shims so they don't fall out. Were they elongated horizontally or vertically?

 

I'm also getting a bit of clunking that recently started when going over those little reflectors they embed in the middle of the road I'm trying to track down. Sounds like it's coming from the rear somewhere though. I hate when I can't find annoying stuff like that......

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The elongation I think I saw was horizontal.

 

Certainly, upper control arms are the other suspect. I initially discounted them as a prime suspect because I've never seen one go bad, but there have been so many things wrong with this 2001 XJ that I've never seen even on vehicles 15 years older and with three or four times as many miles, I probably should assume that they need to be replaced, since everything else in the front suspension has needed to be replaced.

 

Talk about "Just Empty Every Pocket" ...

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We had some clunking noises on the 89 and after going thru the majority of the front end discovered the upper track bar mounting bracket hole was slightly elongated, and no matter how tight we made it, shifting ocurred when going over large bumps. Replaced the bracket and still had a slight clunk - turned out the mounting pins for the DS caliper were worn and it was shifting slightly back and forth...

 

These things can be aggravating sometimes :dunno:

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