So, I bought my 2001 XJ8 base model last year with extensive docs back to 2008. Records indicate upper bushings and shocks replaced 4 years ago. Oddly, lately I'm hearing thuds from front end going over speed bumps, etc. I check the upper mounts and find left side obviously toast, but nothing really visible from right side. I will change both, but it raises a question. What is the cause of upper bushing going bad? In particular, why would one side go noticeably more than the other? I realize after 50yrs of playing with cars, I've just accepted bad upper shock bushings and replaced them without looking for the root cause. Thoughts????
Dave

 

Miles, heat and cold, vibration, poor quality in the replacement (I found rebuilding with neoprene was way too hard, particularly in very cold). My left took more of a beating than right side -- replace with Mahle replacement, seems better than Uro (either much cheaper than OEM from dealer).

 

Make sure you change the bump stops on top of the shocks the are just as important as the upper shock mounts. they are part of the cause of upper bushing failure

 

Thx! Ordered and news when done.