How do you remove the broken off petcock in the block of an

Copperhead don't play · Sep 18, 2016

When trying to remove the drain petcock in the side of an 8N, I rung it off flush within the block. It is brass and two different types of "Easy-out", did nothing but screw into the soft brass. Any helpful advice would be appreciated.

MNGB · Sep 18, 2016

You could try drilling it with a 7/16" bit and then running a 1/4 pipe tap in to clean up the threads, go slow and drill straight in the middle.
GB in MN

Charles Krammin · Sep 18, 2016

I had luck with heating it up lightly and melting wax on it as it cools. the wax melts in the threads. Then the easy out
Charles Krammin

Jim in Western MI · Sep 18, 2016

It might be good to slightly pressurize the cooling system so that any debris will blow outward while you're working on the threads..., air hose in the radiator, etc.

ZANE · Sep 18, 2016

Use a four sided easy out. I threw away all my old twisted easy outs years ago . They just get tighter and make the threads push harder against the block threads.

Zane

DGinVT · Sep 18, 2016

I keep some left hand drills around for things like that. Last one I started to drill out the petcock threaded part came out and I cleaned the hole with a tap.

Bob · Sep 18, 2016

Oh, gosh, a few brass chips in the cooling system ain't gonna hurt a thing vs. pressurizing it and making a mess!

If the OP isn't experienced in extracting broken brass fittings, the easiest thing to do would be to carefully drill it out to the size of a tap drill for 1/4" NPT, which is 7/16", then use a pick or sharp little cape chisel to pop the remaining brass threads out of the cast iron block, then touch up the threads with a 1/4" NPT tap.

Royse · Sep 19, 2016

"I keep some left hand drills around for things like that."

Yep, and if you get to 7/16 in size then pick and tap.
Key is to stay centered and straight.

Copperhead don't play · Sep 20, 2016

Thanks, for all the advice. I got it out.
Copperhead

Copperhead don't play · Sep 21, 2016

As you know the twisted EASY-OUT did not work for me, and I do not have the square type yet.
Well, I tried two types of file handles one almost square and the other rectangle, but it was stuck solid and did not work for me. I though I would snap the files in two; I had so much pressure on them. So, I very carefully drilled and tapped it. If I had a good heat source I would have tried Charles suggestion first.
But thanks for the good advice.
Copperhead

How do you remove the broken off petcock in the block of an

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