I put on G2 LCA's and Adj. Hotchkis PHR-both poly/poly

Now I have this thumping/banging form the rear
or possibly coming from the SFC's-Hotchkis which
share the bracket with the LCAs

It doesn't happen over bumps or when accelerating
but mostly when I'm decel. It kind of feels like something
is shiftly around but everything is tight.

Do these need to break in?

help is appreciated

 

I believe BMR talks about this with their boxed SFC's that weld to the LCA bracket. They say you can get a clunk if you don't tighten the bolts enough after the SFC's are welded on. Maybe that's your problem.

Dan

 

Did you check to make sure that the rear G2 LCA mounts were tight in the frame mounts? If there is any play, you would need to add washers or the mount is going to slide back-&-forth over the bolt.

I installed G2s aluminum rear LCAs and panhard rod (rod-end versions) last month and had to adjust with washers for a tight fit.

Or worse yet, maybe the poly bushings are binding the rear suspension and suddenly unloading on de-celeration. I learned the hard way 5 years ago, that poly bushing rear LCAs were only for drag racing, not corner burners.

Rick R

 

It's tight. I'm starting hear it less so
that's good. The thing is that this isn't
happening in corners.
For example, There is a short block with
2 stop signs. I shift my way to 3rd and
then start to coast, letting the car slow
its way down and THUMP THUMP.

 

Maybe the new poly mounts are transmitting more noise than the factory rubber cookie cutter bushings were. Sounds like something that you are hearing under mild engine braking.

Hard to say what the noise is, but guesses are:
- Loose front torque arm mount? The bolts on my factory TA mount at the trans came loose once.
- U-joint play?
- Did the LCA bolts fit snugly in the diameter of the new LCA bushings? If not this could permit fore to aft movement.
- Are the LCAs or panhard rod missing the inner steel sleeves to fit between the poly and the LCA mounting bolt? If so, this would permit both fore to aft and twist motions.
- Sticking brake calipers or brake drag on slotted rotors?
- Any binding at ride height?
- Any interferences at ride height? LCAs close to big wheels

Again, the LCA bolts can be tight, but there could still be a clearance between the LCA bushings and the frame mounts. If so, then there could be play there.

I currently use a Spohn Torque Arm with rod end connections. There is no thump-thump, but it sure transmits alot more road noise and I can hear more rear differential gear noise. Your poly mounts are going to transmit more than rubber.

Rick R

 

Turned out to be simple, the jam nut on the
PHR kept backing off. After I tightened it for the
2nd time I put some tocktite on it and banging
is gone.
Thanks for the input

 

Mine did the same thing and the jam nut/sealant fix that one, it still rattles but it's the cheaper rod ends that Addco puts on their bars. I guess it's time to get some QA rod ends.