Exhaust Nuts? Rusty

[CirrusSR22]

Anyone have luck getting off the four nuts that join the manifold to the cat/mid section? Mine are pretty rusted so I hit them with PB Blaster and let them sit. I cranked on one and it sheared right off.

Unfortunately the stud heads appear to be welded to the manifold itself, so I guess I need to drill that one out. Thankfully it sheared right at the head of the stud and the stud head looks really thin.

I'm guessing I should Dremel/cutoff the other three nuts? Torch? I'd almost like to get all the studs out and start over with fresh bolts/nuts.

[cooljess76]

When I took mine off, 3 of the 4 heads broke off. I would highly suggest buying new bolts, nuts and springs prior to removing as you most certainly will break off at least one which may leave you without a car while waiting for parts. Same goes for the ones going to the header. Can't remember if those were welded also, but you'll need to figure something out if they happen to break off. Sometimes the gasket falls apart as well.

[CirrusSR22]

I already snapped the two long bolts (with the springs) a few years ago! I replaced them with hardware store bolts, but I probably should have gotten stainless stuff. Although, finding bolts that long in stainless might be tough.

I think I'm gonna try to shear/cut off/drill all the welded studs on the manifold and replace them with stainless bolts and the stock copper nuts. Not a lot of room to work without taking off the exhaust manifold; which I really want to avoid All this work just to replace a center bearing!

[cooljess76]

Originally Posted by CirrusSR22

I already snapped the two long bolts (with the springs) a few years ago! I replaced them with hardware store bolts, but I probably should have gotten stainless stuff. Although, finding bolts that long in stainless might be tough.

I think I'm gonna try to shear/cut off/drill all the welded studs on the manifold and replace them with stainless bolts and the stock copper nuts. Not a lot of room to work without taking off the exhaust manifold; which I really want to avoid All this work just to replace a center bearing!

Yeah, I seriously feel your pain man. Sometimes things go easy, other times I just want to roll it down my driveway and say fcuk it. Hang in there though, it'll get better.

[tiFreak]

is there a little bit of the bolt still sticking out? whenever that happens to my boss, he heats it up with an acetylene torch and twists it out with a vice grip

[elchicano]

i have the same problem. I have everything ready except for the bolts. For some reason at pelican each bolt ran up $20 something dollars! I have tried twice with no luck I might just try again this weekend.

[CirrusSR22]

I just picked up four stainless steel (A2-70) M10x40, 1.5 thread bolts, four stainless M10 washers and four BMW copper M10 nuts. Oddly the nuts on there right now are not copper. They also use one size smaller socket than the BMW copper nuts I just picked up. Hmmmm.....

The stainless bolts were $1.69 each and the stainless washers were $.88 for four.

Hopefully the welds that hold the studs into the manifold will cut off easily with a Dremel cutoff. By the way, these studs don't seem to be pressed into the manifold flange like the 6 cylinder cars I'm reading about on bf.c. It's basically just a thin flange head then directly to the bolt/stud's threads.



Old sheared stud w/new bolt.

[elchicano]

Where did you get the bolts from? I have Jess's old cat outside right now so I'm going to see if i can get everything ready for the weekend.

[CirrusSR22]

I got the bolts from Menard's (Midwest version of Home Depot or Lowes). I was actually surprised they had them though as finding a big selection of metric stuff is tough, especially stainless. This was a super-mega version of the store and they had an extra selection of bolts/hardware. I was planning on going to an Ace Hardware or a "real" hardware store to find them.

[mohaughn]

I had the same problem... Make sure the replacement bolts you buy are not super low grade. Sometimes the stuff sold at hardware stores is not very good, and all of the heat right there could cause them to stretch/break.

When I had my rear bushings replaced the shop removed the entire exhaust system, not sure why but they did. I think atleast two of the bolts snapped, so I just replaced all of them.

[CirrusSR22]

Alright, I got some work done today. Here's what the studs look like. It's hard to see under all that rust, but there are two small welds holding each stud into the exhaust manifold. At least one of those welds needs to be cut away. I used a Dremel with a heavy-duty cutoff wheel. .

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Once the weld is cut away, I used a punch going backwards through the stud hole and popped the stud head off

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After removing the stud head, I filed the flange surface flat and the M10 bolt slipped right in.

[CirrusSR22]

Only two of the four studs is easily accessible, so I figured I'd shoot for the other one. If you don't believe these are rusted badly, look what it did to a 3" 3/8" drive extension! This was not a Craftsman extension like the other one I was using, just an unmarked generic one.


Same thing with this stud. Just cut a weld off and punch it out backwards. A word of caution though. If you don't cut enough of the weld away and start punching it out backward, you'll begin to bend the exhaust flange. You'll know when the weld is cut away because it only takes a couple moderate taps with the hammer and punch to pop the heads off.


Here's what a stud looks like. You can see how thin the head is. About the thickness of a washer.


I used a bunch of Permatex 1,600F anti-seize on the bolts and nuts and snugged them tight. I looked for the Permatex 2,400F Nickel anti-seize but couldn't find it anywhere.

[CirrusSR22]

Now there's still the issue of the other two studs. I see that Lowes sells a 12" long, 9.5mm drill bit which I think I'll use. Hope the stud shears at the head and drill backwards through the stud head. Might take a round file after that to enlarge the hole to 10mm. A very long drill bit is required because of the configuration of the exhaust pipes.

[CirrusSR22]

I got my project done yesterday. I ended up cutting off a third stud head weld with the Dremel, so that just left one stud remaining. I bought a 9.5mm drill bit that was 12" long and drilled the stud head on the fourth.

[elchicano]

Okay guys im a bit confused. I managed to get two nuts out of 2 bolts and one of them broke. The other one i keep hitting it with PB blaster. So the bolts that i managed to get the nut out of how do i get them out. Can i hit them with a hammer until it pops out. I don't have a dremel but my dad has a makita which is the same but bigger. I'm prolly going to finish this tomorrow.