How to remove Exhaust Manifold bolts

I would like to hear from others on their methods of removing rusted 57 year old Exhaust manifold bolts.

I have thought of grinding the heads off and using a pipe wrench on them?

Would it be best to try turning them after tractor has been run a bit so they are nice and hot?

Maybe some of you have some better ideas that might work, please let hear them.

I hate to remove the head and take it to a machine shop and have them drill the old bolts out and re-tap the hole but that may be my last resort.

That's a tough job and there's no easy foolproof method.

I would NOT be turning on them when they're hot and soft, sure way to twist them off.

HOWEVER first having them hot to expand them maybe break from rust and then after cool down try it is my advice.

Of course, a good 6 point socket, NOT a 12 point which is easier to round the heads

I would NOT use any big breaker bar or cheater and put them in a dead high torque pull HOWEVER use a hammer out on the end of the wrench or bar or ratchet TO SHOCK AND SLOWLY HAMMER THEM TO TURN

If they ever turn, go slowwwwwwwwww and turn them in and out in and out a few times.

PB Blaster or Kroil or other penetrants.

If a bolt head breaks Id try to FIRST weld a washer to the stud (if enough is exposed) and then weld a nut to the washer for wrenching them out, instead of a pipe wrench on the stud.

Im sure there are other methods and old wives tales the gents can help you with, the above is whats worked for me.

John T

There is no one fits all solution, but trying to avoid twisting them off is always the goal.

Since this sounds like a planned tear down, start with several days of soaking them down with your favorite rust penetrant. But do use a true penetrating oil, not WD40. Also if you can get to them, use a brass drift and give them a few good hits with a big hammer. If the heads are rusted away, this might even swell them some so a good 6 point socket will fit tighter. (Hint, a 14mm socket is slightly smaller than a 9/16.)

Getting them out hot should be a plus.

If any are studs with a nut, heat the nut, it will come right off.

Just use good sense when you start wrenching them. Feel them out, you can tell if it's unscrewing or just twisting. Sometimes going tighter will help break one loose, maybe work back and forth, if you can get "some" movement work with that, loosening it just a little at a time, back and forth, more rust penetrant.

Those that will not move, cut the head off so you can get the manifold out of the way. Then heat the casting around the bolt, shock it with some easy hammer blows, get on it with good vice grips.

If any do twist off, and you can get a straight shot at then, you should be able to drill them out. Trick is to get the drill EXACTLY in the middle. This takes a good eye and patience. Start with a punch mark, use a 1/8" drill, correct as necessary, drill all the way through the bolt (but not into the head!) Work your way up to the tap drill size of the bolt, then carefully remove the remaining threads with a tap. Never try to use an easyout! It will not work on a seized bolt, break it off and... Well, you know the rest of that story!

Good luck!

Heat the casting, not the bolt, apply candle wax as it cools, unscrew. Tough ones may need second application and more wait time...for wax to penetrate threads. Bolt heats too fast, latent heat in casting helps wax to penetrate. Has never failed me.

Do your best to prevent twisting them off, but if you do, a wire welder and a nut will be your best friend.

I have a method that I have used on D Radiators,520 / 620 exhaust manifolds and many other applications in the NATURAL GAS industry were excessive head was part of the by product.(exhaust manifolds on 16,000 hp turbines / Turbo charger studs on 9000 hp V-16 CLARCK Piston Internal combustion engine)) This method was part of the instruction at TECH COLLAGE back in 1971. It has never failed me. Grinde off the head of the STUD or bolt. Remove component. Place a washer around stud and weld to stud. Then weld a nut to the washer. Once weld is below 160deg remove stud/fastener. Very few men if any can hold their bare hand on metal greater than 130deg !
Bob...

I have never twisted a manifold off when gripping it tight to the head. When I feel resistance that makes me wonder if it might twist it off I apply heat close to the bolt trying not to get the bolt hotter than the head. Trying to expand the head more than the bolt. The nuts that will not come off easy I grind off to keep from twisting between the nut and head. Old rusted studs are normally weakest half way in.
I use a pair of channel locks that can only be ordered special that grip much like a pipe wrench. A pipe wrench should work much the same.

I knew it was going to be iffy as to weather the bolts would come out or twist off. (they have been in place some 57 years) Well I did some pre-work with various oils and potions, some heat and cold, some prayer and cursing and what do you know 3 of the 4 bolts came right out.

Well that 4th one twisted off about 1/4" from the head.

I have tried clamping to it with vice grips and a small pipe wrench it no avail.

My next step it to thread a nut on the peace sticking from the head and with my wire welder weld the nut to the bolt. after it cools a bit I am going to try turning it out.

Grinde off the head of the STUD or bolt. Remove component. Place a washer around stud next to the head and weld to stud. Then weld a nut to the washer. Once weld is below 160deg remove stud/fastener. Very few men if any can hold their bare hand on metal greater than 130deg !
Bob

will work about half the time . i had some i had to drill through and weld back up then remove was the only way to get enough heat in there to shrink bolt

As John Deere D said.

I welded a nut on the tip of the bolt still in the head. Waited a bit till it cooled to the touch then put the wrench on the nut and what do you know it backed right out.

With this kind of luck I am going out this evening to buy a Lottery ticket I can't loose.