i am at the end of my threads

[canadianal]

tried to for the last week and a half to get four siezed exhaust manifold bollts out of my caddys head, got 2 of them but i have so far fairly butchered the other two, i have used heat , drilled them out twisted off 2 ese outs in each one wrecked about a dozen good drill bits and now have come to the decision they are not to be coming out dont know what else to do . any suggestions out there . they just wont drill out to a larger amount and any drill bit i can get other than a really expensiver 1/8 bit would not toutch them , they just come out like powder and then the bits dulls and you dont make any headway. i am ready to bolt the cast manifold back on with new gaskets and some good sealant and live without 2 bolts and see what happens
any suggestions??
i dont know what else to do.
two of the rear bolts were broke off before and it blew the rear gasket as it was old. i now have at least one bolt in the rear gasket and can get some squeeze on the gaskets.

[pat mccarthy]

here is two good tricks. when drilling i use a carbide ball mill 3/16 or bigger much better than a drill and will drill alot of tuff stuff but not cheap .i use the tooth pick type ezout and go as big as you can on the hole to use the biggest ezout out so it will not brake . and you can .heat it up and use and toilet bow seal the yellow wax type on the part you want out this works the best and try again

[76GMC1500]

Take it to a machine shop and make them deal with it. Some shops have a fancy process that uses a special welding electrode to dissolve the bolt out of the hole. I also recommend you have it magnafluxed after heating, if you got it hot enough to glow.

[techinspector1]

"uses a special welding electrode to dissolve the bolt out of the hole"

Electrical Discharge Machining (EDM)

Give it one more try using Pat's suggestion. Heat the end of the stud with a torch and push a candle up against it. As it cools, it'll suck some of the wax in between the threads. Then lay a hex nut on the end of the stud and weld through the nut hole to the stud end, filling up the hole with weld. Then you can try using a socket on the nut to twist the stud out.

[FMXhellraiser]

Originally posted by pat mccarthy
here is two good tricks. when drilling i use a carbide ball mill 3/16 or bigger much better than a drill and will drill alot of tuff stuff but not cheap .i use the tooth pick type ezout and go as big as you can on the hole to use the biggest ezout out so it will not brake . and you can .heat it up and use and toilet bow seal the yellow wax type on the part you want out this works the best and try again

USE this tip! Use the Carbide milling bit with FOUR tips at the end, not TWO teeth. I don't know what you call em but I call them teeth or tips. It will eat right through those bolts. Get you some HEAVY DUTY Lubricate and spray the crap out of the bolts first, let it sit and then get a punch or something and TAP the bolt a few times with a hammer. If they are all stripped already then the carbide milling bit will get those suckers out of there easily and won't break like your HSS drill bits.
I dont have time to read this whole thread so sorry if I repeated what someone else said, I will come back and read this tomarrow when I get home!
Good luck!

[pat mccarthy]

ball end mills. the teeth are called flutes. four flutes is for steel and two are made for soft stuff some types of aluminum. and yes you need to be rigth on center .the ball end mill is the one you want this will drill a hole .spray penetrant will burn off. i like the wax. it wick it self in the threads. i have tig weld a tower up with weld .the tig dose this very good and you can control how much weld you put down. and the heat it makes when welding helps to burn the junk out like sealer and lock tite and grab the tower with vise-grip you can weld a nut to it but the zinc plated nut s some times weld like crap . tower works the best for me

[Big Tracks]

Yeah, canadianal, those old crystalized bolts twist off easy, don't they? It's a common problem with the big Cadillacs. They run a little hot anyway, and If somebody ever tried to lean one out more than normal to try to get better mileage the exhaust gas temp gets really high.

I twisted off five or six bolts before I broke down and took my 500 heads to the machine shop. I learned a long time ago that you get some very unkind comments frrom the machinist if you take him a bunch of botched attempts at drilling out broken bolts or studs.

Good luck.

[FMXhellraiser]

Yes flutes that is it. Heh I was talking about using lube BEFORE you break them not after you broke them already haha. I already went through about 5 problems like this on my 66 and broke a bolt off in the caliper (the only bolt that holds the caliper on) Well lets put it this way...There is still no bolt in there. After that I learned to take more time and lube the bolts (rusted ones) up really good, let em sit, lube them again and tap the screw, bolt, whatever with a hammer and THEN go at it.

[Ives Bradley]

You could also try a masonary drill bit. Dip the carbide tip in water or oil often and it will drill out lots of metal.

[halftanked]

If you've already drilled ,and now have an easy out broken off in the hole,you don't have alot of choices. You can use acarbide tipped ball as has been previously suggested and try to go after it that way which will use up several of them,but will work, and as a last resort [I do it often,but I'm nuts] put your smallest cutting tip in the old gas ax, set gas at 7 lbs,oxygen at 40lbs ,with an 1/8 inch flame ,heat the easy out til you just barely see a puddle form,and give a quick blastof air, go slow,repeat go slow

[firebird77clone]

I like the torch suggestion. very risky, but after you break off an easy out, not many choices left. That easy out is HARD.. so even with a carbide four-flute ball end mill, you have a chore ahead of ya. Before you try to mill it out, you could heat the end of the easy out cherry red, that'll take some of the hard out of it.

Tip for the future... if the bolt shears off because it is seized up with rust, an easy out will NEVER work. If the bolt sheared off from over-torquing, then you have a good case for an easy out.

Another tip ( just remembered ) is to SMACK the bolt with a hammer ( 32 oz ball peen ) before you try to remove it. Sometimes that will bust up the rust some. Penetrating oil is sometimes helpful on exhaust bolts, but not usually, as it just cannot get to the threads. ( bolt is too long )

Last tip: for exhast studs, ( or any rusty nut ) heat it till it is dull red ( or almost dull red ) and apply some light oil ( turbine oil works well, available in appliance parts stores and has a wonderful extendable tube spout ). the heat will draw the oil into the threads. Repeat several times, and the nut will usually come off with a minimum of resistance.

Your best choice for a twisted off bolt is always to drill it out and run a tap down to clean the threads. Drilling free-hand, my chances of getting a perfect center is low.. and I do try hard! A center punch helps, as does starting with a 1/8" drill and stepping up by 1/16"s.

If ya flubber up the threads by drilling out, you might be able to drill out and tap to the next larger bolt size. You can also helicoil, which also requires overdrilling. There are several thread inserts available, which require overdrilling as well. Usually, the helicoil gets the job done with a minimum of oversize.

Sometimes it is better to just 'cut your losses' and take off the head, and bring it to a machine shop.

[R Pope]

I've torched lots of bolts like you have, and a quick pass with a threading tap usually cleans the threads up. If they are chewed up from drilling, a Helicoil might be necessary.
A tip--set the head on a flat surface outside, gasket surface down so it kinda seals on the table, and run a garden hose in the coolant passages to cool it while you gas-axe the bolt. Messy but it works. Duct tape seals some other leaks and keeps the water where you want it.

[halftanked]

Hi again,Icut it short the last time, The tool steel of the easy out will burn out easily,then try for the stud,trying to establsh a hole through the middle first, then to a side,don't freak if you go into the threads a little,it will still hold a bolt good enough to give the clamping action you need. We're dealing with three different metals here,tool steel,mild steel,and cast iron,and the cast iron is water cooled,and also of far greater mass so it acts as a heatsink