Removeing broken water pump bolts

[gs spoken here]

This worked for me, and only cost 1$. Used a 5/16 1 inch long roll pin. Remove old pump, if the broken stud in not flush with the mating surface, flush it, being carful not to damage surface. Clean the old gasket from the water pump. Support the under side of the pump on 1x2 blocks so the impeller does not hit, this will form a level surface to in-large the broken stud hole to 5/16". Drill press works the best. Then the roll pin will slide into the 5/16 hole. Bolt the water pump back on the front cover with at least 2 bolts. insert a 3/16 drill bit into the hole in the roll pin, it just fits, and drill out the broken threads. the 1/4-20 tap, need about one larger drill size to tap, but it is easy to in-large the hole, the initial pilot hole is the difficult one, with a steel bolt and alu cover. It worked for me.

[elagache]

Thanks for the tip! 

Edouard 

[WkillGS]

Great method, I'll have to try that next time, Thanks!
Keeping the bit centered when drilling is the most difficult part of removing broken bolts. I use a hand drill, and start with a small pilot hole. If that gets off-center, use a slightly larger bit and start drilling at an angle to correct the centering. Repeat until you get to the final size.

I like your method better!

[cwmcobra]

Great thinking, Bill!  That's a piece of ingenuity!   

Chuck

[TrunkMonkey]

Outstanding pilot solution.   

That one can be used in several situations.

[GS66]

Nice! What is the method for when the bolt is broken off inside the block?

[gs spoken here]

Jim, I am lucky I did not have to go there. This is a 68 GS350 car and the water pump was loose and made noise. Someone else had put a pump on it a long time ago and had broken off one 1/4" bolt and not fixed it. They also left out another one, not sure why, the threads were good. The 4 long 5/16" bolts, 3 came out with a 3/8 ratchet, the 4th took a long time with a 1/2 breaker bar, and a lot of back and forth, maybe should have used some heat. The long bolts get gummed up, steel on alum. If I had broken one of those, I would be taking the front cover off to deal with if. Not sure how to center that one. Someone on the V8 board said Snap-On makes a $80.00 unit that does not work.

[GS66]

Thanks. I have one on one of my 401 motors that?s rusted through or broke off or something in the block. So no bolt in that hole for years but no water leaks so far either!

[Rollaround]

Brilliant! Thanks for sharing.