Rear Shackle Angle Symptoms???

1995 XJ 2 Door
4.5" RC LA suspension lift
AA SYE
TW Cardian DS
32x11.5R15 Mud Claw radials

Installed suspension lift and got driveshaft for the rear. Odd thing is that there is sometimes a loud thump or bang coming from the rear suspension when making turns at slow speed where the ground isn't level.

It seems to be a suspension cycling issue as it had the same issue without the rear driveshaft installed. I retightened the sping bolts and the u-bolts and drove it for about an hour today without the thump occuring. Ran it up to 60 mph and no vibrations issues what so ever. Then on way home tonight, made slow left hand turn crossing a rut and "Thump" showed back up again. I can't get it to repeat and its just a single thump. It's loud.
No signs of damage or interference issues under the jeep. Cycled suspension with jack and no issues.

I am thinking it has something to do with the shackle angle (but the shackle is not vertical, about 5 degrees past vertical). I have google searched and found the posts regarding the shackle angles and one mentioned sounds yet didn't describe them. Like I said, its not a regular occuring sound and I can't get it to repeat at will. Really ran it hard for an hour under varying conditions without any issues.

Any thoughts?

5 degrees past vertical going what way. A pic would help. Regardless 5 degrees in the correct way is no where near enough angle. That along will make it a harsh ride suspension wise. The suspension will bind up alot befor it actually let's the shackle do what it is suppose to do.

magimerlin said:

. Regardless 5 degrees in the correct way is no where near enough angle. That along will make it a harsh ride suspension wise. The suspension will bind up alot befor it actually let's the shackle do what it is suppose to do.

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/\ This. Are you running RC full leaf packs? One thing i noticed about there pack when i first got there kit a few yrs ago, is that there leafs have a sh** ton of arc and no length to them. Causing the shackle angle to be what you discribe. Eventually they will settle and flatten out giving you a better shackle angle but begin to sag quickly. As for the noise...I would also check the torque on the leaf spring u bolts and main eye bolts. I chased a banging for almost a yr with there kit. Found out it was the POS 2.2 shocks. Running BDS leafs and bistein 5100 now. Wish i had done it sooner.

Yes, I am running the full leaf pack in the rear.
I torqued the u-bolts down yesterday thinking that was the issue but the noise still popped up. I was thinking overnight that maybe I didn't grind enough off at the lower shock mounts and the shock bumpstop plate was striking the oem shock mount on the diff housing. Could be striking the oem mount when the lower shock bushing compresses. Will look at tonight when I get home from work.

Also was wondeing if I have the spring hanger bolts too tight and the shackles are binding up. Plan to try and look that over as well tonight.

Rear springs are stiff yet it rides decently at 50 mph. Even ran it over a local RR crossing that is in terible shape at speed and it handled well. I saw a post were they recommended putting bags of sand in the back to load up the springs and get them to settle in.

any idea if there is a way to check the shocks without replacement? Not sure why it wouldn't be more frequent if I had a bad shock in the kit.

I'll post a photo tonight with the shackle angle. google search seemed to show an issue if shackle was vertical.

I think i stuck a couple hundred pounds in the rear of mine for a few weeks to soften up the ride. When my 2.2s crapped out, they were banging all the time. Best way to check though is with them removed. Cycle the shock by hand. If there is any latteral play in it before the valving kicks in. There done.

Do you have a locker? Also check your trans mount.

Think I found it. I retorqued the springer hanger bolts then took it out and beat on it to see if I could get the noise to occur. Drove 40 over a bunch of speed bumps and no issues. Think the sring was binding in the mount and then letting loose sideways since the hanger bolts loosened up. No noise since.

It actually rides decent for a lifted truck and handles pretty good. I know a lot of guys bash RC yet the kit seems like decent quality for the price, everything was in there, and no real issues installing it. Biggest headache I ran into was dealing with the old brake lines. I have about 75 miles on it (all road) at this point.

As for rear springs, they are really stiff. I jacked up the passenger side rear tire at the lower shock mount. The springs compress yet there is still about 3 inches of travel left in the shock before the driver side tire starts coming off the ground. Tire doesn't even come close to contacting wheel well.
Thanks