Did it fail due to heat damage or did the impact cause it to shear and the leakage caused it burn up? That part is mostly designed to take some angular miss alignment. It is too short to tolerate any parallel miss alignment or any side loading from impact. If the muffler is completely supported off the engine as done with the factory Waterboxers that flex connection should not be needed for vibration. Having the cat in that location probably is not the best place due to expansion putting a side load on that part. I would suggest welding that part on the pipe in line with the cat, not the down pipe. Then it can take the vibration and also the expansion-contraction of the cat in the direction it will work with. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Neil N
Sent: Thursday, February 6, 2014 6:20 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Exhaust Bushing Inner Weave Premature Failure

Hi all.

I know various popular Vanagon engine swaps use this type of part so I assume it's ok to ask here. I installed this bushing:

http://www.dynomax.com/media/catalog/product/cache/1/image/690x380/9df78eab33525d08d6e5fb8d27136e95/f/l/flexpipe_1_1_1.jpg
    on my engine swap. (image of it installed):

https://lh3.googleusercontent.com/-ozMqBRgLXD8/Ubu5n5CAFoI/AAAAAAAAHvU/P9YKIPdcSMI/s500/Exhaust%2520v3%25203.jpg

For various reasons, I knowingly installed the bushing so one end was slightly cockeyed. Regardless....

Have any other folks had this part fail prematurely? Would the
cockeyed install cause it to wear prematurely?   (I think the answer
is "yes")      ;)    Maybe this type of part is better? Image:
http://www.clublexus.com/forums/attachments/rx-first-generation/123665d1210187402-exhaust-flex-pipe-issues-pict0012.jpg

A campground mishap (below) caused the part to fail. Muffler Works on hwy. 101 in Florence were great. They did good fairly priced work and were patient with my many questions. I asked to see the old part noting that about 1/3 of the inner weave was burned off (gone). This after only about 6000 miles. The inner corrugated sleeve had obviously been exposed to lots of heat so the slight bump to the exhaust caused the bushing to crack. I wish I'd payed more attention to the part installed. Not sure if it has the same type of construction, but it looks the same.

Thanks,

Neil.

On a dark and stormy night, backing into a campground spot at Beverly Beach state park, I nudged my tailpipe or muffler onto the cement stop block.

Got myself over to Muffler Works in Florence who did a good and affordable repair job.

I asked to see the failed flex bushing. The inner weave was burned off
(gone) on one side. The corrugated piece had cracked once I nudged the exhaust system.

--
Neil n

Blog: tubaneil.blogspot.ca

'88 Westy http://tinyurl.com/c8rlw6p

'81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/

Vanagon VAG *Gas* inline-VR Engine Swap Group:

http://tinyurl.com/d7gd5ej