Sealing exhaust donuts??

[genzzel]

I got all 3 donuts, bolts and springs to fix a leaking cat, but can not get them to seal. Cleaned the sealing surfaces and all, but no luck--completely that is. Is there some trick to getting these to mate and seal??? Thanx kevin

[RojoRocket]

Are all 3 joints leaking?....just one??? If the doughnuts are fresh and the spring-bolts are installed correctly the hardware works surprisingly well. Not to be a smart-a$$, but after similar experience with mine I have to ask; "are you sure that the leak is where you think it is?" My leak turned out to be a crack hidden under a heat-shield just inches away from where I was 100% certain it was.

Glenn

[SuberNatural]

I had all 3 of mine replaced, a flange welded on, and new hardware at cole muffler for $79

[genzzel]

May be some other leaks--put in donuts to fix leak and when rechecked you can see where exhaust gases are blowing by. Almost seem out of round, flanges that is, and new donuts do not seal well--thought there might be some trick to help them seat.