HRA Pipe Rebuild

This will be short as I'm not rebuilding mine, but I do have to rebuild my BMW muffs and it won't take much to pull the HRA pipe I have apart to inspect. After having done this, I can safely say your HRA pipe is one most excellent piece of equipment and Al is to be congratulated for selling high quality stuff. Parts, construction, and packing are of the highest quality. Just keep it painted on the outside to discourage rusting and it should last for years. Smile

The pic above shows the pipe on the left, packing screen in middle on the bottom, and the end cap on the right with the 4 rivets that were removed. Item in the center is the screen and packing caps off my BMW muffler. They are the same size. The 1/2" black pipe & coupling up top was used to drive off the end cap after getting the rivets out of the way.

Grind off the rivet tops or drill them out with a 3/16" or 5/32". If you grind the heads, tap out the remainder so you can slide off the end cap. Use a 2+ft. of something and a hammer to drive the end cap off through the inside of the muffler.

When you have it cleaned out, wrap the screen with packing, insert all into the end cap, then tap the assembly back into the pipe. Align the rivet holes as you do this as the end cap should fit firmly into the pipe end. Pop rivet 4 - 5mm rivets to hold the cap and you are done.

Packing Material: Pack it with whatever fiberglass you can find and wind the packing on as firmly as you can if you want to replicate the original packing Al supplies. The original stuff is super dense, far denser than I was expecting. (Far denser than the packing from my BMW pipes) You need 1" thick packing. It goes 7 1/4" into the pipe. The pipe is 3 1/2" in diameter so you need 11" in length to wrap all the way around the screen. I would tape the wrap onto the screen. Use any tape as you care not if it burns up later, you just want to keep it firm while you tap it into the pipe.

Well, that is what's needed and required to do the job. Pretty easy if you have the tools. Less than an hour of work.

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Cool. Thanks Rufus. I think my pipe had some work done by the previous owner. It's got a minor rattle. Maybe I'll get in there and play with it someday...

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2005 Chetak