drb007

I am putting on the primary muffler bypass (Cup ) pipe, and I can't for the life of me get the exhaust to stop leaking at the joints. I have spent a couple of hours messing around with the damn "gasket" coupler things and I still have no luck. I got the drivers side to slow way down by lightly hammering the gasket (is that what it is called?) into the cat end, but the passenger side is blowing like crazy. I think it has gotten even a little worse as I drove it for a few days, and it is driving me nuts. I am almost ready to put the muffler back on. It is supposed to be so hard to get a good seal or am I missing something?
Dave

garrett376

Maybe your bypass pipe has a different style mating surface, requiring a special gasket?? I know that when I diassemble the exhaust, it's a no brainer to hook it back up leak-free - I would therefore assume you've got a mis-shaped pipe, or it simply requires its own special "gasket" coupler.

Just a thought... maybe call the guys you got the pipe from - they might tell you that you need a special gasket.

drb007

Good thoughts, but the pipes look very good and round, and they are the same bend and form as the muffler ends. By the way, I ended up with two Cup pipes, and have tried both of them.

Bill Gregory

Dave,

They can be a pain. You might try sanding the 'gasket' to smooth out any irregularities. To my knowledge, there are no special 'gaskets' for any of the cup bypass pipes. It's fit and try, fit and try, have a fit, fit and try, until successful. When I installed mine, one end worked almost right away, however, the other took a number of attempts until sealed.

Colin 90 C2

When I installed my Gemballa primary muffler( equivalent to a cup bypass pipe) I had to unbolt the catalytic converter to get enought slack. Then it was easy to fit the gasket and clamps. Finally you then just have to tighten back up the cat.

Good luck
Colin

springer3

Check the surface finish on both new and existing parts. Both should be smooth, flat, and very clean. Try looking at the fit-up with no gaskets or clamps in the way. You should be able to get easy metal-to-metal contact all around the mating parts. If contact is at only one spot, your faces are not parallel. Either something is bent, or one of your other exhaust connections is off a little. The advise to loosen other clamps is good. If the mating faces are off-set, that needs to be fixed before trying to install the gasket and clamps. Trying to pull things into alignment with the clamps is a losing proposition. The exhause cycles to extreme temperature with each drive, and any built-in stress will cause problems.

You say you have been driving with the leak. Very bad idea - you said the leak got worse. The hot gas could have damaged the gasket or possibly even cut the metal sealing faces. Check everything for alignemnt, and for smooth, flat, and clean surfaces. It should bolt up and be leak free the first time if everything is right. If you find something out of alignment, it is a good idea to loosen all the joints, and get them in harmony with eachother. It could be that a small difference between your old muffler and the new pipe was accomodated in the other system joints. It is not possible, in my experience, to pull a bad fit together using the clamps. The fit must be correct in the natural position, and the purpose for the clamps is to press everything together and keep things leak tight. Good luck.

drb007

Thanks guys. I did as you all recommended. I spent a fair bit of time sanding all of the surfaces and the gaskets, really loosening all of the clamps, and then carefully aligning everything. Worked much better. I found I was also overtighening the clamps, which caused some of the leaking.

Thanks for the help guys!