From searching, I found plenty of topics on the 6x manifold to down-pipe studs, but none on the 2x 3/8-16 studs that connect the flange to the silencer.

Are these threaded or welded in? I'm missing sections of thread, so they're not usable. Has anyone ever replaced these before? I suspect I will end up drilling them out and using hex bolts instead, but am curious whether its possible to thread them out.

The other option is to get a new y-pipe - it's probably about time anyway - but I do not see an aftermarket CA compliant direct-fit y-pipe for the 2002. I asked AB about theirs, the magnaflow, and its for the 2003 only.

 

I think it might also be a carriage bolt


but I'd prefer not to waste a day pb-blasting only to find out it is indeed welded.

 

Hi Jeff, I know it's a PITA but is it possible to grind off and drill out the existing studs and replace them with 10 or 12mm nuts and bolts preferably stainless steel. I am facing a similar issue on a TD5 exhaust flange.

 

They are not welded in.

Heat the flange with a torch and beat them out with a hammer.

 

Perfect. Thanks

 

Mine after ceramic coating
jeff,
check the magnaflow site. They do have ca compliant cats but not y pipes for some reason if i remember correctly. I ordered the none oem and federal compliant ones. Got em ceramic coated and gotta pick them up when I get back in. I took my old y pipe and sold it for scrap and got $120 for the cats but forgot to get the 2 bolts out before I took em so I'm gonna get some exhaust bolts and just bolt them up tight.

 

Rock auto has a y pipe by David for a little over $700 that is California carb compliant

 

Thanks Jason. I forgot to check RockAuto. Well the y-pipe does work, as far as I know, so I will replace the studs and run em dead

So you bought the cats separately and had a shop weld up a new y-pipe?

 

I ordered the completed y pipe from magnaflow but not the oem style ones. Since I'm in Alabama, I'm not required to do emissions testing. I'm only required federal emissions. Since they were new, I had my buddy go ahead and ceramic coat them to hopefully help keep the heat away from the from double cardigan joint and burning the grease out. If it lowers the temp some, I'll be happy. I use that Lucas red and tacky that can withstand over 500 degrees so if it keeps it under there, great. I'll still grease em every oil change

 

The only weird thing about the magnaflow y pipe was, it was a two piece unit. The drivers side has the full pipe and the connection for the muffler and the passenger side has the pipe that slides into the y and it help in place by a exhaust clamp. I gotta get new bolts though. The old ones reminded me of a wheel stud like they were hammered/pressed in and then locked down when you tightened it up. The new y pipe didn't come with em though