On my 91 XJ laredo, the upper control arm bushing thats on the axle side(the mount that sits on the carrier) is complete shot. I dont even have to get close to see that the bushing is nearly destroyed and pieces of it are hanging out. Thats how bad it is. Would this cause a thump that I can hear and feel through the floor board where my feet are? It only happens when the Jeep is moving and I apply the brakes and I jog the steering wheel back in forth a certain way.

 

yes that would definetly cause a thump

 

Are the poly bushings worth the extra money? Ive heard they create more vibrations but flex alot more and last a very long time.

 

go poly. rougher riding, longer lasting

 

if your still on stock arms i would upgrade all together go to a ball joint eliminate further problems