Loosening seized nuts etc exhaust system

[Higsy]

I have got some problems removing the exhaust system etc on my 1985 Carrera 3.2. I have managed to remove 5 out of the 6 hex fastners with 8mm allen key but the sixth won't budge and the allen key has now stripped the hex socket in the fastener. It's pretty inaccessible so I can't see how I could, say, cut the stud & fastner off above the flange. Should I drill out the stud to the top of the flange?

Second problem are the nuts holding the flange. Have only managed to remove 2 of 6 despite soaking for a week with penetrating fluid. 2 of the nuts seem to have part rusted away so cannot get any purchase with ring spanner. The other 2 are just rusted solid. Should I cut them off? If so any suggestions as to tool to use. Will one of these small Dremel tools with metal cutting disk do the job? Any ideas?
Thanks
Mark

[88911coupe]

The first thing you might try is a really good set of hex wrenches. I noticed some of mine would just round off or literally twist then I pulled out my really good set. Of course they'd been thoroughly soaked in PB Blaster for 3-4 days. You may have to just go up a size and jam it in there. Also, I used a dremel type tool on several of mine that were really rusted. When I sent the heads off to Competition Engineering they removed all the old stubs and replaced them with new ones.
One thing I thought may work is using a Sawzall type cutter with a really long blade flush against the flange.
Good Luck

[tom1394racing]

I have had good success on the hex and barrel nuts with a Dremel cutoff wheel.

The Dremel is small enough to allow you to cut through the nut and then use a chisel to split if from the stud.

[JohnJL]

I've found welding a fresh nut to the top on the seized one often does the trick...the heat of the welding breaks the grip and the new nut gives you a better grip.

[Robs72T]

This is what I used. Bought it here on pelican.

Tool

[Flat6pac]

Removing the cam carrier allows access to the nuts. Put heat on them and it will help. Years ago it was $50 to replace abroken stud, I bought tanks to heat with and have saved a bunch of cash and time

Bruce

[lucittm]

If those are original Porsche nuts, they are hardened steel. Many years of rust will soften the exterior just enough to allow a wrench to round off the hex nuts or an Allen to round out the bolt head. For the 6-8mm size, a hacksaw on the offending nut works for one or two. Buy a dremel and a diamond wheel at Home Depot for more that two, and go slow. You will be SO happy that you did.

For the 10-12mm size, I pull out the oxy-acetalene torch and blow the nuts off. Life is too short to struggle with those.

Then replace the studs/bolts and nuts with A2 stainless steel. You can get it at Grainger. You (or the next owner) will be grateful.

Mark

[Browzer52]

Originally Posted by lucittm

If those are original Porsche nuts, they are hardened steel. Many years of rust will soften the exterior just enough to allow a wrench to round off the hex nuts or an Allen to round out the bolt head. For the 6-8mm size, a hacksaw on the offending nut works for one or two. Buy a dremel and a diamond wheel at Home Depot for more that two, and go slow. You will be SO happy that you did.

For the 10-12mm size, I pull out the oxy-acetalene torch and blow the nuts off. Life is too short to struggle with those.

Then replace the studs/bolts and nuts with A2 stainless steel. You can get it at Grainger. You (or the next owner) will be grateful.

Mark

Replacing exhaust studs with stainless is probably not a really good choice,grade 5 studs are the better wat to go.Stainless tends to get brittle after being heated and allowed to cool countless times,eventually on removing or attempting to do so will break........ever tried to drill stainless?

[lucittm]

Browzer,
You are right about most stainless steels such as 410 and 316. The A2 series is a high-temperature, corrosion resistant alloy developed exactly for this application.

Grade 5 is hard and good for high-tensile strength, but how tight will our exhaust flanges really need to be, 170,000 psi? I doubt it. And, it corrodes at high temperatures. I'll stick with the A2.

Mark

[Browzer52]

Originally Posted by lucittm

Browzer,
You are right about most stainless steels such as 410 and 316. The A2 series is a high-temperature, corrosion resistant alloy developed exactly for this application.

Grade 5 is hard and good for high-tensile strength, but how tight will our exhaust flanges really need to be, 170,000 psi? I doubt it. And, it corrodes at high temperatures. I'll stick with the A2.

Mark

Grade 5 is a standard bolt where grade 2 is a shear bolt.The grade 8 and better is where you get into a high tensile rating.Grade 5 is easily drilled and is why I would steer away from a stainless fastener.From what I understand about stainless is that the constant heating and cooling of this material renders it brittle and apt to break on attempting to remove.Standard exhaust studs are a grade 5 rating.Have had to drill these studs out once before on my 78 SC(now sold)and am looking at this unsavory chore again as I am removing an original exhaust system from my 86 930.Have requested info on A2 stainless from our fastener supplier and will consider it as an alternative to the standard stud .....if I can get the old ones out.Thanks for the input.

[Geronimo '74]

Originally Posted by tom1394racing

I have had good success on the hex and barrel nuts with a Dremel cutoff wheel.

The Dremel is small enough to allow you to cut through the nut and then use a chisel to split if from the stud.

+1
Same goes for me!

[Porshaah]

I like stainless but I'd be concerned with the galvanic action at the aluminum head. Never had much luck with PB Blaster and the such - that 3-4 days is long one. Heat it till it's red and if you can still get some kinda tool on it while it's hot - maybe one of those comeouts that Bob Villa is always pushing from Sears, I think you'll have success. It's very rewarding if you get the nut off with the stud still intact but if you can get a Dremel in there that would be quick.