Broke off an exhaust mainfold bolt

[mnccnm]

Well, while removing my exhaust manifolds to put a Banks kit on my 1990 F350, (7.5l), I snapped the front bolt on number 8 off flush, (the back one was already flush). I've drilled the hole, and sprayed the heck out of it with liquid wrench. Other than patience, any other advice? I'm a little nervous about using a torch as I've sprayed so much liquid wrench on this thing over the last few days I'm afraid it may go up in flames.

 

[73F100Shortbed]

Reverse drill bit. Sometimes it will back out. Or drill stud out and re-tap it.

 

[mnccnm]

Ya, Ive got the easy out in the hole, letting the penetrant soak in. Maybe I should just keep drilling the hole larger and retap instead of risking the easy out breaking?

 

[73F100Shortbed]

If you are sure you are dilling straight it may be easier. I've had luck both ways.

 

[mnccnm]

Straight as I can working through the wheel well. I'll give the penetrant some time first.

 

[73F100Shortbed]

Well if you drill then tap it you have to be pretty sure you are straight or won't work. You could try heating it a little after the penetrant dries.

 

[mnccnm]

I'm hoping that getting the one out will be enough to make the seal, as the back one has been missing for awhile, and I can't fit the drill in there. The flanges on the headers are 5/8" thick.

 

[73F100Shortbed]

The gasket will blow out if the bolt isn't in the back.

 

[flareside_thunder]

I agree with the reverse drillbit.....I will never EVER use an easyout ever again......EVER. Penetrant or not on the head, I'd still use the torch...get it CHERRY red.

 

[mnccnm]

When you say reverse drill bit, are you referring to the thing that is like an easy out, but spiraled? That is what is what I am using.

 

[73F100Shortbed]

It is a drill bit that drills in the opposite direction in your drill

 

[flareside_thunder]

Nah it's a drillbit but reverse cut......

 

[mnccnm]

And how does the reverse drill bit remove the broken screw? Can I still try this, but use a size slightly larger that the hole I have already drilled?

 

[Fellro]

They are basically the same thing as a left hand drill bit, they bite in, and since you are drilling the same direction the bolt turns to come out, they will sometimes actually turn the bolt out. If it is rusted in too well though, you just end up drilling it all the same.

 

[mnccnm]

The gasket will blow out if the bolt isn't in the back.

Sigh. Pulling the heads just isn't in the cards right now.
To correct myself, the broken bolts are both on number 4, and the front one of number 5. The back bolt on 4 and the front bolt on 5 have been broke off for a long time, with no leaks, (no gasket, machined surface).
I am considering using maybe a copper gasket, but due to current time and finances I think I will have to take my chances until I get the motor done.

 

[Alvin in AZ]

And how does the reverse drill bit remove the broken screw?
Can I still try this,
but use a size slightly larger that the hole I have already drilled?

1) "by accident"
2) Yes you can try it, I never have. Own some tho.
3) Picture it, the idea is for the left-hand-bit to remove the piece as soon
as it loosens-up and is ready to come out. If you've drilled really crooked it
might not twist all the way out for you but will jam. No sweat on the jam,
but the left hand drill bits -could be- faster.

IME, if the bolt is too stuck to be able to turn it's own threads and would
rather twist off, a little easy-out ain't gonna work neither. :/ IME, almost
the whole works is going to have to be drilled out anyway. :/ And when it
gets thin, the easy-out wants to spread and pinch the threads! So the
left hand drill bit might be really cool that way?

Easy-outs suck.
So, having to resort to easy-out sucks too then.

Did you loosen the bolts when the engine was hot or wait to straight-up
remove them when the engine was cold? Something I haven't tried either,
but read several places the "smart way" to do it is to loosen those babies
up when the engine is hot, if you know (and can) ahead of time.

Alvin in AZ
ps- Where should I send the carbon copy? To Minnesota or New Mexico?
(fill out your stuff)

 

[mnccnm]

I went and got a couple left handed drill bits, and drilled these holes. So far, as usual, the easy out is worthless. I tried the torch a few times, but the Mepp gas will only get it so hot.

I'm thinking to keep using the left handed bits, increasing in size until I get to 5/16 and then try to clean out the threads with a tap.

Do these holes look centered enough? Straight enough to do this?

The holes go all the way through the bolt stud.

 

[O'Rattlecan]

Well, there is a bolt remover kit that includes both a reverse drill bit and another piece that spirals into the opening and bites into the new walls you've created. Just using the drill bit won't do the trick.

Ryan

 

[mnccnm]

The spiral piece is what I'm using. Any more force and I'm concerned it will break off.

 

[crzybil87]

At this point i would just drill out the hole a bigger size and re-thread it