In the last month, I've noticed a clunking sound coming from the back of my series 1 XJ6 (like someone hitting an out-of-tune drum) when turning left, mainly at speed. It doesn't really happen when going slowly. It's been getting worse with time, and I can't figure out what it is.

Please help if you know what I might be dealing with!

 

Was that on my car - but in the left front...

 

I've figured out what it was. A metal hook that inserts into a suspended rubber socket holds the exhaust piping away from the wider medial part of the drive shaft near the brake disc, but the rubber has perished and split, making the pipe sit about half an inch lower. When turning left at speed the car rocks to the right, so the medial part of the left drive shaft angles upwards and bashes on the exhaust pipe

 

 

I am currently working on the temporary exhaust system on my 86 XJ6 V8 conversion.

Like you, I have found out how important those particular exhaust hangers are.

If they have lost integrity, the pipes start knocking on the caliper / cage / driveshaft etc. particularly the flange that is a part of the intermediate muffler, where it tends to contact the front lower portion of the cage as the pipe passes into the cage.

Good rubber hangers and then lining up the pipes to pass through the cage and rear valance, without touching anything can be a hassle. Finally found the "sweet" spot on mine.

I think the best time to finalize the pipes / mufflers location is, when the pipes are new and moveable against each other. Once they are connected and maybe a bit rusted, it is difficult to change their relative position without using heat (torch)

As I mentioned in a previous post , my plan is the swap over to outboard rear brakes which will allow more clearance for pipes passing through the cage.