Broken Head Bolt

[Ranger Mark]

I was installing the driver side head and broke the last bolt on the bottom closest to the firewall. It broke off uneven below the top of the block, and when I tried to drill it out the hole ended up being off so an easy out won't work. I'm at the point I may have to use a thread insert. Is there one that will hold 70 ft. lbs. of torque? The bolt size is M10 1.5 x 127mm thread length is 74mm

 

[Uncle Gump]

Are those torque to yield bolts? Did you replace them? How far below the deck? Holy Smokes!

That's not a good position to be in... depending on how far below the deck... weld a bolt to it and try to back it out. Can't say I've ever repaired a head bolt hole with a thread insert. Good Luck...

 

[Dirtman]

How in the heak did you break a head bolt installing it.

If you can get to it with a carbide dental drill you could start a pilot hole in the center to start drilling it out...

 

[pjtoledo]

how bad is it? are the heads still on? did drilling go off far enough to hit the block? did you get to drill into the bolt at all?

try a piece of steel rod, grind the end so that when rotating CCW there is a bur sticking out that may grab the bolt.

take a long allen wrench that won't quite fit the hole in the bolt. cut to make it straight, grind tip to where it has a sharp angle, (not a point) pound it into the hole cutting new flutes as it goes.

put a small chisel into the hole,,CAREFULLY smack it a couple times to create a slot, then use screwdriver to remove.
be certain to hit the same spot, you don't need 3 or 4 different small slots......use this method only if desperate, may cause the bolt to expand,,,very undesirable.

here's a good one, if you can get any kind of rod into the offset hole in the bolt,,,, then put a tap into the hole with the rod in one of the flutes of the tap. see if you can turn it that way.


if the head is off, piece of cake. all you need is a nail and small hammer.

it's too late now, but when drilling broken bolts always use a guide tube to center the drill. broken bolts have hard and soft areas, they don't drill straight.

free advice, take it for what it's worth.

 

[Ranger Mark]

How in the heak did you break a head bolt installing it.

If you can get to it with a carbide dental drill you could start a pilot hole in the center to start drilling it out...

Well, basically, I bought new head bolts (felpro) and installed the passenger side head no problem. When I started on the driver side I torqued everything to 34 lbs. Then on my way to the final of 70 lbs. bolt #2 in the sequence broke. I was able to remove the head and get the bolt out cuz it was above the block. Upon reinstalling the head the exact same thing happened but with #3 in the sequence. Figured 3rd time is a charm but I was sooooo wrong. I broke #7 in the sequence on final pass. How the hell I broke 3 brand new bolts is beyond me. Autozone replaced them but I'm stuck with a broken bolt in my block.

 

[Dirtman]

You sure your torque wrench isnt in newton meters or something? The probability of getting that many severly defective head bolts is astronomical.... Something aint right here.

 

[Ranger Mark]

how bad is it? are the heads still on? did drilling go off far enough to hit the block? did you get to drill into the bolt at all?

try a piece of steel rod, grind the end so that when rotating CCW there is a bur sticking out that may grab the bolt.

take a long allen wrench that won't quite fit the hole in the bolt. cut to make it straight, grind tip to where it has a sharp angle, (not a point) pound it into the hole cutting new flutes as it goes.

put a small chisel into the hole,,CAREFULLY smack it a couple times to create a slot, then use screwdriver to remove.
be certain to hit the same spot, you don't need 3 or 4 different small slots......use this method only if desperate, may cause the bolt to expand,,,very undesirable.

here's a good one, if you can get any kind of rod into the offset hole in the bolt,,,, then put a tap into the hole with the rod in one of the flutes of the tap. see if you can turn it that way.


if the head is off, piece of cake. all you need is a nail and small hammer.

it's too late now, but when drilling broken bolts always use a guide tube to center the drill. broken bolts have hard and soft areas, they don't drill straight.

free advice, take it for what it's worth.

A couple ideas I will try.

Free advice is always worth what you pay for it. If it helps you got a bargin.

I appreciate the help.

 

[Uncle Gump]

Well something was out of wack... maybe your torque wrench. Clicker types can get funky if you pull on it wrong.

 

[Ranger Mark]

You sure your torque wrench isnt in newton meters or something? The probability of getting that many severly defective head bolts is astronomical.... Something aint right here.

8 bolts on one side and no issue. Can a torque wrench just go crazy? I agree it is up there with alien abduction on chance of happening, but I have no other explanation.

 

[Ranger Mark]

Well something was out of wack... maybe your torque wrench. Clicker types can get funky if you pull on it wrong.

OK. You may be on to something here. I did have the hood prop rod in my way and it may have affected my pull. Do you have any more detail on that?

 

[Curious Hound]

I'm with Dirtman. Something is amiss and it seems you have the torque wrench set wrong.

Aside from that, you might still be able to re-drill the broken screw. I would try putting the head back in place. Find a piece of thn-,walled tube that fits in the hole in the head and use that as a guide to keep your drill centered and straight. You may still be able to drill a centered hole in the broken bolt and use an easy out t of remove it.

Helicoil would be the best insert to use for repair threads because it is thin and doesn't require as big a hole as many other styles of inserts. Their website should give an idea of how strong the resultant repaired threads will be.

 

[Uncle Gump]

All torque wrenches need a smooth straight steady pull. I support the head of the ratchet with my left palm... ensure the the ratchet is level and a slow steady pull on the handle til it clicks. I've had to get into pretty ackward positions to get into a position to make that happen.

 

[mikkelstuff]

Yes, very very odd with either old or new head bolts. I would at least check your torque wrench against another - a rental from the parts place if nothing else.

 

[Ranger Mark]

I was

Are those torque to yield bolts? Did you replace them? How far below the deck? Holy Smokes!

That's not a good position to be in... depending on how far below the deck... weld a bolt to it and try to back it out. Can't say I've ever repaired a head bolt hole with a thread insert. Good Luck...

yep. They are TTY bolts.

Longer one is the old bolt, the other is new.

The depth of break is at about 1 1/4". The calipers are at the depth of break to give an idea against bolt size.

This is the best picture I could get down the hole.

 

[Dirtman]

I have no idea the specs for the 3.0 but most torque to yeild bolts dont use a final torque setting in foot pounds. You set them to something light like 30 foot pounds and then turn them 90 or 180 degrees to finish the process. Not insulting you or anything but are you sure you followed the proper procedure?