• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

LCA bolt tightness

Timber

NAXJA Forum User
Location
Slohio
All right, first a bit of history.
I previously added some WJ LCAs and consequently spread the axle-end and frame-end brackets a bit wider (per Gojeeps's writeup). The bushings went bad in those control arms, and I bought new standard XJ arms. Putting those in involved pulling the brackets back together a bit to fit stock XJ arms. I know I'm now over the factory torque spec., and when the rear bolts are out I can "bounce" the arms when the axle-end bolts are in. In other words, with the rear bolts out, I can push down on the arms and they will spring back up. Should they do that, or does that mean I've overtorqued the front bolts?
I can't remember what they were like before I started fiddling with them.
 
When the bolt is torqued correctly, the metal bushing in the center will not turn, but the rubber bushing surrounding it will flex, so it should bounce when disconnected at the other end. If they don't spring back, the bolts aren't tight enough. It's a rubber spring, not a rotating joint. Because the bushings are tight, and the rubber flexes when the axle moves up and down, make sure that you tighten the bolts only after the axle is on the ground, bearing weight, so that the default position of the rubber bushings is unflexed.
 
I imagine the recommended torque for the bolts should crush the sleeves back tight enough.

The metal center sleeve of the bushing, not turning with the arm, that is CORRECT. Except, the force and speed the suspension arm are going to move is far greater than what you'll do by hand. So, just because you pulling on the arm a bit, might NOT move that center sleeve on the bushing, DOES NOT mean its tight enough that it won't turn when going over big bumps in the vehicle. I'd use a torque wrench and torque them to spec.

I just did it last night on my '95 XJ, 133ft-lbs LCA (all bolts)
66ft-lbs UCA (at body), 55ft-lbs UCA (at axle), 62ft-lbs Track Bar (at body) and 74ft-lbs Track Bar (at axle).

And like Matt said, do it with the vehicle at rest on the tires on level ground, you have to pin down the bushings at their default position, i.e. the bushing has zero deflection with the suspension is at its normal position, so the bushing equally fight the suspension up and down with increasing resistance as the bushing deflects greater in a given direction.

If you have to tighten down a bushing to improvise and jocking the bolt holes to line up, then after getting all the bolts in, loosen up the bolts again put the vehicle on the ground with tires to tighten them down.
 
Thanks for the info., guys. To date, I've always worked on the arms with the full vehicle weight on them, so that's not an issue. I'm sure they're torqued past 133 ft. lbs. (though I didn't bother with a proper torque wrench due to having to pull the sides back together), so tonight after work I'll loosen them and then torque to the proper specs. Thanks again.
 
Back
Top