broken exhaust stud now what?

[Cdnone1]

Please help. I am back dating the exhaust on my 82 Sc to 74 . Well I have been soaking the nuts in penitratin oil and heat cycling them for a week. Today I put a wrench on the first one Tried to tighten it a little , it moved then went to back it off and it snapped striaght off in the wrench. Now I'm scared and have an undrivable car that will need at least one stud repaired. I am desperate for advice, thoughts,etc.
thank you all
steve:

[Doug Steinel]

I had the same problem (snapping off exhaust studs) until I took the advice of a Porsche mechanic.... heat the nuts until they are cherry red and then back them off. I haven't snapped off another exhaust stud since I took this approach. As for the broken one, drill it out.

[Cdnone1]

Do you turn the nut while it is hot or wait for it to cool? is there a tread that explains how to drill it out for us DIY people? thanks for the advise
steve

[makaio]

You turn the nut while it's hot.

I don't remember hearing of anyone being sucesfull with using a hand drill only to drill it out. You need a jig to hold it perfectly straight.

[vash]

yes, just went thru with this. i had a buddy heat those suckers up with MAPPgass and then i held the socket closeby at the ready. it was pretty cozy down there with the two of us huddled under the car with a active torch, but every nut turned off easy. dont forget that thing is hot! so dont drop it on anyone or anything. a nut shaped tattoo on the forehead is not cool. as for the broken stud, sit tight. some folks here have done it, and i am sure they will chime in soon.

[wrx paul]

I did mine with a cordless makita and some drill bits from sears. Sears sells some in a black case for hardened metal. They go thru the stud like they're made of wood. Start small and work your way up to almost the same size. Then use an extractor. I'm not sure I remember where I got them but I think it was sears. They are a tapered square thing that you can hammer into the hole you drilled and the stud will back out if you're careful. It can't be too hard since I did all this on my back under the car.
When your done the stud should come out and look similar to a heli coil.

[oneblueyedog]

If you have a piece of the stud left sticking ou tof the head. You could weld a nut on. Heat up the welded nut and stud and carefully back it out. You really do need a jig to drill them out. Not many can center a drill in the stud on their backs. I think people have made them and you might find info on it if you search. There is a famous picture in Bruce Anderson's book that shows a hack stud replacement job on a removed head. I think he said it was functional in the caption.

Try PB Blaster again before twisting anything. Use heat on the nuts that remain to take the exchangers off.


Lee
78SC

[johnsjmc]

After removing the rest of the exchanger nuts(with a torch)and exchanger you may be able to remove the remains of the broken stud with vice grips Heat around the base of the broken stud will swell the metal away from the stud and it will wind out if you have enough room to get a grip on it.

[fred cook]

Step 1. Don't panic!

Step 2. Get a torch. Even a small oxygen/mapp gas torch (about $50) will do the job. You will need several cylinders of O2.

Step 3. CAREFULLY heat each nut until it is glowing red, let it cool until it is no longer glowing and the do it again. Usually 3 or 4 of these cycles will break the rust bond enough to get the nuts off. The barrell nuts are larger and take longer to heat evenly.

Step 4. Once the heat exchanger is off, use a piece of thick cardboard to make a template by pressing the cardboard against 4 (if possible) remaining studs. If you make your drilling guide with 4 holes, you can replicate the location of any of the studs by turning or flipping the guide plate. Take the cardboard template to a machine shop or a friend that has a drill press. Use a 5/16" drill to drill 4 holes in a piece of steel at least 1/2" thick. If everything went well, the drill guide will just barely slip over 4 studs. While you are out, pick up a timecert or other thread repair kit. If you want to drill a pilot hole before going for the big bits, make an insert that will just press into the holes. Center the insert in the drill press and drill a small hole in the exact center.

Step 5. If part of the stud is extending below the head, use a collet type stud remover (made by several companies) and while applying heat to the head, try to unscrew the stud. With enough torque it will probably break even with the head which is what you want it to do.

Step 6. Put the drill guide over 3 good studs so that the remaining hole is over the broken stud. Use the insert to drill a guide hole and then use a 5/16" drill bit being careful to keep it square with the head. The guide plate will help a lot, but most drill bits will "wallow out" the hole in the plate if you are not careful. Drill the hole deep enough to go completely thru the broken stud.

Step 7. Remove the drill guide, Use the special drill in the thread repair kit to enlarge the hole slightly and using the tap that came with the kit, thread the hole for the thread insert. Use the special tool that comes with the insert kit to install the new threads. At this point, all that is left to do is to install a new stud.

I know this sounds like a lot of work, but compare it to dropping the engine and pulling the head off!

Good Luck!

Fred Cook
'80 911SC coupe (been there, done that!)

[Trust Me]

OK I'll say It...... If you break it, you're F*cked! Listen to the advice. Do a search for the topic. RRRRRRRR. I hate exhaust studs!!!!

[Cdnone1]

Thanks to all who have offered great advise. Here is where I am at so far. The right side heat exchanger is off. Two of the studs came out clean from the head on one cylinder the other 4 studs broke of clean at the flange. I am going from thick flanges to thin so I've got 2 clean holes I can insert 2 new studs into. I have got 4 studs with enough thread to cover my new (74) heat exhangers.
Should I try and remove the other 4 studs but double nutting them heat and PB blaster or just install the heat exc and spacers and bolt it back together.
I can't thank everyone enough for the advise.

Thanks again
steve

[vash]

ok, sounds like you have enough material to grab. i once used a cheapo stud remover from kragen to save the day on my camaro. but if i were you, i would get a good stud remover. like from snap on. get all new hardware with your new exhaust. if it is worth doing.... do it right!

did you use heat to remove the other nuts? doesnt sound like it if you broke some more. good luck!

[Hugh R]

Excellent advise above. When you put it back together, use an anti-seize exhaust compound so that you don't have the problem again. Good Luck!!

[Cdnone1]

Thanks
yeah I heat cycled them about ten times then had them glowing when I tried to remove them. All the heat seemed to do was find the weakest link since the nut/bolts where rusted together as one
steve

[Trust Me]

Because..............They suck!!!!!!!!! LOL. Too many beers. Good night.

[Schrup]

Check out this thread, it is the method I was going to use untill I pussed out & took it to John Walker.
Duck food

[vash]

aww man, that sucks steve. heat and they still broke? i didnt go thru any heat cycles. just heated once and cracked them off. i would try to get the broken pieces off now. with any luck, you will need to take them off again in the future, and now is as good a time as any. sucky gamble tho.

good luck, please keep us posted.
cliff

[filou]

Been there, done that.
What a b____H to get off but i did it. Just one more thing : For the remaining sticking out studs, i use little socket that you hammered in on the stud and you use a wrench to turn the socket. the sockets are differents sizes made to accomodate differents studs diameters. If you look inside the sockets, it has a helicoidal king of tread to grab the studs. KD tools made those. Ask your car part dealer.
My friend who own a car shop let me borrow his sockets.
good luck because you are going to need it.
Sock those studs with some kind of lubricants or some others chemicals mentioned earlier.
Truly, Phil.

[Oldporsche]

I have removed exhaust studs and nuts with, hack saws, dremels, oxy-acetyline torch (my favorite) stud removers, vice-grips, special bent wrenchs, crowsfoot wrenches, flex-sockets, etc.

I held my breath on every one. I kept my mouth in the same smile. Sometimes it worked sometimes not.

I generally heat the nuts to high drip with the torch. I get the wrench on it as soon as possible. I make sure before heating the nut, I have the tool ready to remove it.

Somewhere in one of the threads, there is a picture of a guide made for drilling the stud. You might try john walker's workshop.

You will get some pretty good advice here. Just read all of the posts. Many on here have had the same experience. Some of it was good, others bad.

Good luck,
David Duffield

[Cdnone1]

thanks for all the respones.
it has been nothing but a disaster. Everything that could have broke or gone wrong did. I soaked in PB heat cycled and heated to cherry red and still it all sucked. What was suppost to be a 2 day upgrade has now left me with a un drivable car in a state of undrivable for the next few weeks until I can repair and replace everything to get it back on the road.
Oh the joys of owning a 22 year old car.
At least it still has the right name on the back and when I do get it on the road it is still more fun to drive than anything else I know
thanks again
steve