So I have a broken bolt in my PS pump location. I have used this drill bit before to drill out a water pump bolt. Is it the right size for the bolt I am working on now?

Solid-Carbide Twist Drill Bit 25/64" Drill Size, 3" L O'all, 1-1/4" Flute Length


WAnt to make sure since they are like $40 each. THanks.

 

25/64" = .391". That's larger than 3/8" = .375".
So no, that wouldn't be what you want. Unless you're drilling for a helicoil?
If you're just using a left hand drill to remove the broken bolt, use a 5/16"
left hand bit. center punch it first and use a 1/16" bit to center drill it, then use the 5/16" left hand bit. Heat and cool it to try to break it loose first.

 

yeahm I am just helicoiling it. Thanks for the advice on the punch though. You you say that, you mean just taking something with a hard point, and hammering the center, to make a dimple?

Thanks.

 

Exactly, to make sure your drill bit doesn't wander. You gotta drill that really straight.
That drill bit should come in the box with your 3/8" helicoil kit. I'd try to remove the old bolt before I helicoiled it. All kinds of new hassles come with that, since you have to seal it from leaking as well. (which bolt is this?)
If you're set on helicoiling it, go nuts, but be wary it's dead centered.

 

PS - Congrats on 3000 posts, woooo!

 

I have heli-coiled a water pump bolt before.

The bolt is the upper PS bracket bolt hole.

So to describe it further, it is the one on the lower right. There are two one ontop of the other. The bolt is broken in the top one.


----------------------

Yay! a lotta posts, lol

 

I'm trying to picture it now. Does it go into the heads? ie, into a water jacket, or into a blind hole?
You shouldn't have a problem then, now that I realize what you're doing.