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best way to remove broken exhaust studs?

crazy240

crazy240

New member
Joined
Jun 16, 2008
Location
Austin TX
I have 3 broken exhaust studs in a 940 turbo head. Whats the best way to remove them?
They are all sticking out with some thread but won't budge. I would prefer not to drill and tap but might not have a choice..
Can i apply some heat with a torch around the stud or will that warp the head?
Always been lucky before and never had this problem..
 
Get someone with a welder to come over, really does make life easier, also if you can get the manifold back on and start up and run the car a few heat cycles (idling to temp) with some penetrating oil it can help also.
 
thelostartof said:
Get someone with a welder to come over, really does make life easier, also if you can get the manifold back on and start up and run the car a few heat cycles (idling to temp) with some penetrating oil it can help also.
Click to expand...


i was able to get a few broken studs out like this...
one head I had to pull and send to a machine shop
 
I was able to get all of them out without heat except 1 bastard that is now broken off inside the head..
Can I just run to home doper and get a grade 8 bolt, drill and tap it to that? Or do I need exhaust stud material to hold up?
 
crazy240 said:
I was able to get all of them out without heat except 1 bastard that is now broken off inside the head..
Can I just run to home doper and get a grade 8 bolt, drill and tap it to that? Or do I need exhaust stud material to hold up?
Click to expand...

Have you ever tried to drill out an exhaust stud? The surrounding material is softer than the stud. You'd have better luck using a left hand drill bit.
 
lummert said:
Have you ever tried to drill out an exhaust stud? The surrounding material is softer than the stud. You'd have better luck using a left hand drill bit.
Click to expand...

i used this to drill a pilot hole dead center
guide_10.jpg


then i hit it with the left handed drill. the last ones i did the drill spun it out without furhter trouble. i use a fractional LH drill that is just under the tap drill size

'easy out' is a 50/50 chance it will snap off in there, based on my one time good luck and one time bad
 
I made a jig that gets held down by the remaining exhaust studs to keep my drill bit straight and used a 1/4" cryo-treated cobalt steel drill bit from home depot, followed by a tap to make new threads. really, as long as you can keep the drill bit centered, drilling and tapping isnt anything to be afraid of
 
naterhater said:
I made a jig that gets held down by the remaining exhaust studs to keep my drill bit straight and used a 1/4" cryo-treated cobalt steel drill bit from home depot, followed by a tap to make new threads. really, as long as you can keep the drill bit centered, drilling and tapping isnt anything to be afraid of
Click to expand...

I pulled my head and stuck it in a drill press, used a LH bit with hopes that it would come out, got to the bottom, and it finally cam out looking like a helicoil :lol:
 
745 TurboGreasel said:
Welder will still get them if they are about 1/4" below flush.
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this.

just make sure you have extra nuts around. some times it takes a couple of tries to get the stud to come out. also, sometimes it is easier to weld on the end of the stud to build it up and get a good weld on the broken stud.

the lostartof and i have had nearly a 100% success rate with welding a nut on the stud. after that the next best on is the using the manifold and a bushing to center drill the stud and use a left hand drill to get it out.

and F*** easyouts. they seem to break more then they get stuff out. i have on more then one occasion used the welder/nut method to remove a broken easy out, and then used the same method to get the stud out also,


good luck!
 
I've had luck drilling and then using a carbide burr in the Dremmel to get most of the old stud out. Easy outs are only effective when they are just removing a shell of the old stud. If you really mess things up, get a Timesert kit and be sure to order the starter sleeve that doesn't come with the kit.
 
The welder trick works super. I pulled two broken studs this way - on the car. Hold the nut on there (vice grips work great) stick the tip of the mig welder in the open end of the nut, pull the trigger for a couple of seconds. Wait a minute for it to cool and see if it turns out. If it doesn't come right out, soak it in penetrating oil, wait 1/2 hour and try again. As was stated before, you may need to try a couple of times.
 
I'll +1 for the welder trick. I've done some serious damage to cylinder heads drilling and re-drilling trying to get all kinds of easy-outs to work. Just weld a nut on whats left really well and unthread the whole thing. It feels awesome when it works
 
The reason the welding method works is the aluminum head dissipates heat a lot quicker than the steel stud, so the weld only sticks to the stud.
 
I've also used the "crayon trick" for broke studs and seized bolts. It won't work if the bolt/stud is sheared off level with the head, but if you have something to grab onto and you've already gotten the manifold off you can do this. Apply heat to the area surrounding the stud and then you take a wax crayon and hold it to the area where the threads go into the head. The wax melts and gets drawn into the bolt hole and "lubricates" the threads. Put your vice grips on the broken stud and try working it back and forth. You might need to do this a few times to get full penetration, but usually the stud will just screw right out once you break it loose.

I think this works better than penetrating oil because when you apply heat the oil will just burn off, but the wax has a higher burn/evaporation point so it sticks around at higher temps.
 
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