What bolts? Exhaust.

[nostromo]

For the life of me I cannot find which bolts will fit and attach these three connections. The whole thing is completely rusted so I will not be able to reuse what's on there. Can someone please tell me specifically what bolts I will need to order for each connection (A,B,C)?

Thank you in advance.

[Daox]

They're probably an M8 bolt. However, you can really use anything that fits. A 5/16 or maybe even 3/8" bolt may fit.

[avguy]

I know that B and C would be 1/2"x1-1/2"for Walker exhaust components, but have no idea if the other manufacturers use the same flange hole sizes. If you're using Walker, although a smaller diameter bolt can be used, the 1/2" is a perfect fit and eliminates any possible sideward movement of the flanges. And a 1" length bolt instead of 1-1/2" would also probably be fine, but the longer length allows the lock washers and nuts to be easily turned on, even when you're in awkward positions under the vehicle.

The cat-to-front-pipe connection (A) is a whole other ball game, the details of which depends on if you're reusing the factory cat, or buying a new one. Are you planning on trying to keep the original cat? If so, get your battle suit out and have it ready to go when you get to that part of the job.

[nostromo]

The cat-to-front-pipe connection (A) is a whole other ball game, the details of which depends on if you're reusing the factory cat, or buying a new one. Are you planning on trying to keep the original cat? If so, get your battle suit out and have it ready to go when you get to that part of the job.

So I've read.

I am going to leave the old one on. Am I correct in assuming that they are studs welded directly onto the cat? In that case, I would only need new nuts to put on?

[avguy]

.... I am going to leave the old one on. Am I correct in assuming that they are studs welded directly onto the cat? In that case, I would only need new nuts to put on?

I've done this on an '05 and an '06, so what I'm reporting is based on those 2 years only. The bottom 3 cat studs were fastened to the front pipe at the factory by something other than the nuts used to attach the top studs to the exhaust manifold. I have a feeling that they just epoxied these undersized threaded connectors, but am not certain about that, because it's difficult to say much of anything about the rusted mess that they turned into. In any case, the bottom line is that, assuming they have become rusted in place, these things can NEVER be unthreaded. And, even if they could, the lower part of the threads are trashed beyond any possible hope to be reused.

But perhaps the factory used a bigger and better connector on the '08, which protects the threads and allows unthreading. If that's the case, and those threads are in good shape on yours, you can just happily rethread the connectors, sit back, and have a cold beverage.

Now, assuming that those bottom threads on your cat are rusted and trashed as all 6 of mine were, you have a decision to make. The first possibility is to trim the the studs off the cat flange; drill holes into the flange where the studs are located; squeeze some thin retaining nuts into the very limited area above the flange; and then use right-sized bolts to attach the front pipe to the cat.

The second possibility is to use the remaining (good part) of the studs to attach a trimmed-down coupling nut. Then the front pipe flange gets attached with M10x1.25 bolts (cut to the exact length required), passing through some type of bushing, such as 5/8" nuts. And the front pipe flange holes probably will need to be enlarged as well, depending on what make exhaust parts you're using.

I've done one of each of the above, and both of them are basically a tedious PITA. The third choice of course is to simply weld the front pipe onto the cat flange. I can say for certain that welding is the easiest and (by far) the least time-consuming way to attach the front pipe to the cat. But the other 2 methods will work if you care to invest the time and effort required to get either of them done.