CAT problem air leak?

[NY cruiser]

Annoying problem!!! took the cat off and when i put it back on i bough all 4 gaskets front and back on both. but for some reason the flanges have air leaks. we tried various things sealants,etc. nothiong works its verry annoying. my mechanic says its b/c its old the system. if i get a new cat-back exhaust the problem will be gone. But i prob will need new cats to b/c it leaks at the flanges b4 the cat. i dont know what to do annoying sound. Any help and adivise appreciated.


My crusier is a 93 locked and OME lightly modded

 

[landtoy80]

OEM gaskets?
Did you clean up the flange real good with a wire wheel/Dremel?
Did you put the right gaskets on the right place?

You need to clean up the flange or it will leak.

Check your manifold to exhaust pipe to for leaks. Its easy to replace the manifold gasket with the cats off.

 

[NY cruiser]

Yes bought only OEM gaskets

everything we tried and nothing works. We tried everything you stated. Lantoy thanks for your help if you have any ideas please let me know