Front axle vibration

I have an 01 XJ with 3 inches of lift. I recently joined after being a user for a few years and you all have helped me through EVERY problem on my Jeep. I am having issues with from end vibrations at about 50 mph and highway speeds. Last weekend I replaced the ball joints and U joints in the front axle. This help a lot with the response of my steering but i am still having the vibration up front. My front driveshaft has been removed for a few months due to this vibration. My ultimate goal is to get the driveshaft back in. With the DS in I experience more vibrations than without. I also have Rustys adjustable lower control arms and track bar/brace. The bolts holding my lower control arms on seem to be worn down. The holes in my LCA's are .575 and the bolts are .500. These bolts seem to be a special kind of bolt but then again I am very unsure. When bolted up I can grab my control arms and shake it a very little amount. I am thinking this is another big part of my problem. Does anyone have any knowledge about these bolts? Any help and advice would be greatly appreciated.

Thanks,
Elliott Jones

Stock LCAs or aftermarket? Stock LCAs take M14-2.0 120mm long bolts, ISO property class 10.9 hardness. If you've got 1/2" grade 8s in there, that would explain the looseness!

I'm not sure it'd explain the vibrations, but I guess it could, and it's probably not a good thing to have it like that. You can pick up OEM bolts as part number 3420 2118 and nuts as 1150 2814 from a variety of companies, my favorite (and the cheapest I can find so far) is zmjeeps.com. If you go to a Fastenal they probably can hook you up for cheaper, you just need to know how long the threaded portion of the bolt is and how long the unthreaded shank is before you order, and all my bolts are presently in my Jeep so I haven't had a chance to get this info.

I have the Rustys Adj LCA's. I do have a fastenal nearby. I also noticed that the bolts seem to have a larger section closer to the head. Thanks for the help

hmmm... are they already metric then? I seem to recall the stock bolts being like that, but I've never seen grade 8s with a step.

Maybe they are but on the micrometer they measure at .500 +/- and the holes in the control arms measure at .575 this is why i am confused and unsure.

I just tried Fastenal and they do not carry any metric flange bolts. Would this bolt have to be a flange or could I put a washer on both the bolt and nut? any ideas?

Just spoke with Rustys Offroad about the control arms and they informed me that they make there lower control arms for a 9/16" bolts and the uppers for 7/16". This answer my question about the LCA bolts. I am now on my way to the hardware store for some new bolts to hopefully some this problem


Thanks

Elliott

The front end still has a shimmy (slow vibe) to it over 50mph. the shake feels like it is coming from the front left but then again im not too sure b/c that is where i sit lol. The new control arm bolts really helped with the slop in the control arms but I am still getting that shake in the front end. Any more ideas on what it could be?

thanks

Check the ball joints. Anything else under there worn or sloppy?

I just replaced the ball joints last weekend. Yesterday I changed the TRE at the pitman arm which has some slop and that helped even more but i still feel that wobble/shimmy at highway speeds. When i replaced that TRE i thought that i could almost feel some slop in the steering gear box ill have to check that out again.