HS40 broken muffler bolt

[copyman]

Hi

What is best way to remove a broken muffler bolt? Engine was badly rusted and when I went to remove exhaust to rebuild engine the one rusted bolt broke off flush with block. I've been spraying with rust penetrating oil until I find out best way to remove?

Thanks

 

[Mr. Pink]

This guy demos several methods of removing a broken bolt.

 

[kram350]

Heat it, center punch and I mean get it on center, drill for an easy out. Get a straight easy-out, not the spiral kind, drive it in and turn it out. If you have a welder, weld thru a nut to the stud and try to wrench it out. If aluminum block the heat from welding will help. If all fails metal disintegration machining or spark erosion will work, but not cheap.

 

[f4radar]

I never have any luck with an easyout on those small broken bolts. When I try I always end up digging the broken easyout out of the broken bolt. I have the most luck with center drilling the bolt as large as large as I can without messing up the block threads, then digging the the old threads out and run a tap through the original threads to clean out the old tailings. In my experience those broken bolts are only in there 3/8-1/2 inch and they're not very hard steel.

 

[Lizardking]

I never have any luck with an easyout on those small broken bolts. When I try I always end up digging the broken easyout out of the broken bolt. I have the most luck with center drilling the bolt as large as large as I can without messing up the block threads, then digging the the old threads out and run a tap through the original threads to clean out the old tailings. In my experience those broken bolts are only in there 3/8-1/2 inch and they're not very hard steel.

X2 on this method for a broken exhaust bolt.

 

[creia]

I never have any luck with an easyout on those small broken bolts. When I try I always end up digging the broken easyout out of the broken bolt. I have the most luck with center drilling the bolt as large as large as I can without messing up the block threads, then digging the the old threads out and run a tap through the original threads to clean out the old tailings. In my experience those broken bolts are only in there 3/8-1/2 inch and they're not very hard steel.

That has been my experience as well ^^^^^^
Michael

 

[Venom38]

I never have any luck with an easyout on those small broken bolts. When I try I always end up digging the broken easyout out of the broken bolt. I have the most luck with center drilling the bolt as large as large as I can without messing up the block threads, then digging the the old threads out and run a tap through the original threads to clean out the old tailings. In my experience those broken bolts are only in there 3/8-1/2 inch and they're not very hard steel.

Yes, not much meat to that bolt. Fresh drill bit and drill it out.

 

[SAT]

Left-hand twist drill bits, heat and Gibbs Penetrant.
The left-hand twist can sometimes spin the balance of the bolt right out.
Saves digging with a bent pick and small needle-nosed pliers.
Good post.

 

[River Rat Ron]

Not going to beat this horse but I will add a little trick an old mechanic taught me when I was busting knuckles in the 80s. After heating the block in this case, try tightening the bolt just a red one before loosening.

I prefer when just the head snaps off so I can weld a nut over the stud.
That way I can break it again in the block requiring drill n tap.

Normally when I’m building a motor I would suggest anti seize on a steel bolt when installing them in aluminum.
On a hot exhaust not sure it would make any difference

 

[Mr. Pink]

Normally when I’m building a motor I would suggest anti seize on a steel bolt when installing them in aluminum.
On a hot exhaust not sure it would make any difference

I've always been a proponent of using anti-seize on any part that gets hot or is prone to rust.
Spark plugs - but never on the first two threads.
Wheel lug nuts.
Any exhaust parts that will someday be removed.

Remember, a little goes a long way.