The Stovebolt Site Forums The Shop Area Driveline Master cylinder bolts

Taking my master cylinder off my 58 Chevy 1/2 ton today both bolts broke off flush with the frame mount.

Getting the right bolt is no problem, but where do you find a GOOD drill bit (or bits)that will drill through these hardened bolts?

We have a couple of ACE Hardware type stores here, and their bits aren't much. Walmart bits are a joke.

I'm going to have to drill them out and re-tap the welded nuts on the frame.

Any better suggestions?

I'm not much of a welder, and there really isn't any thing to try to weld a nut to or I would give that a whirl.

The hme improvement stores have some good quality tools. Start with a small bit keeping it on center & keep drilling it larger & larger till you get to the edge of the threads. Then run the tap in it. Do not force the tap. If it hangs up back up & drill it a little larger. If you break the tap you are in trouble.

Are you sure there are welded nuts on the frame? My '56 has a nut plate with 2 threaded holes in it. I fabricated a new one when I went to dual cylinder.

http://www.jbhardin-gallery.com/trucks/nutplate.jpg

Cletis, mine is not like that. Sure wish it were, would make life a lot more simple. The nuts are welded to the back of the plate. You can feel them by reaching around the back side of the plate.

Another option might be for me to try and knock them off the plate and then I wouldn't have to worry about trying to drill and tap the holes. Would be my luck the plate would bend before the tack weld on the nuts broke loose.

It's 60 miles to the closest "Home Improvement" store for me.

Not much around in my area to choose from.

Oh well. Another day, another challenge.

Thanks wrenchbender. I knew I would have to start small and work my way up. But finding good quality bits in my area is tough.

Most will drill through mild steel pretty well, but get a good hard bolt and you better have a good supply on hand.

I usually buy a few anyway if I have to do a job like this. Also, I grind the end of the broken bolt so that it's a good flat surface and it's easier to center a pilot hole. They don't usually break off nice and flat. Is there any way to weld a nut to what's left of the bolts? If you use one whose inside diameter is a little smaller than the bolt diameter, you might be able to apply enough weld material down into the center of the nut to get it to work.

One is broken off flush with the plate, the other is broken off in the hole a little bit.

If I were any good at welding I might could get one out by welding a nut to it, the other I'll have to drill out. But i can't weld worth a durn. No telling what I would burn up trying to do this.

Don't know why they would be rusted into place now. The truck ain't but 53 or so years old now. LOL

Guess I'll see how it goes this morning. At lest the engine and transmission are out of the way right now. If the tranny were still in place it really would be fun.

Center punch the broken-off bolts as close to center as possible, then use a center drill to start the hole:

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=369-1840&PMPXNO=16770031

Follow up with increasing sizes of high speed steel screw machine drills- - - -they're short and stubby, andd less likely to break. They're also very high quality high speed steel construction:

http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=302-2014&PMPXNO=2618939

ENCO has been in the machine shop supply business forever- - - -I've done business with them for at least 30 years. Good prices and quick service!
Jerry

Eveyone's ideas are dead on. I've seen or done just about every one at some point. I even saw a guy grind out a bolt with a diamond tip bit. It took a steady hand, but he got it done. If you've ever used and "easy-out" you'll find it an oxymoron. The only way easy-outs work is to use lots of heat. Whatever you choose, good luck.

After Cletis mentioned it I think there is a bar back in the channel that is threaded for the bolts. It could be stuck to the bracket. Try hitting the broken bolts with a punch.

Well... got the broken bolts out. On this truck there is no bracket on the back side of the MC mounting plate. There are two nuts that are welded to the back side of the bracket.

I found some cobalt bits here in town and bought them. Also picked up a 7/16 NF tap to clean or thread the holes.

While drilling when I stepped up to a larger bit, the bit finally caught the broken bolts and drove them out the back side of the open nut.

The nuts were in pretty bad shape with rust, I chased the threads, but was not impressed. When I went in with the new bolts I snugged them down, then put another nut with a lock washer on the back to act as a jamb nut.

That master cylinder ain't going any where now.

But the bolts were not going to come willingly through the front. They did twist through the back after the bit finally caught.

Sooo.... that project is done. next is installing the new rubber brake lines for the front wheels and the rear axle.

Found another use for my power steering pump pulley puller. The jaws are just right to hook on the brake lever to push the pedal out of the arm for removal. Works like a charm.

Any way. I do appreciate all the suggestions. Other than having to lay under the truck to do the drilling, this turned out to be some what easier than I thought it would be.

Thanks again guys.

Glad to hear it worked out. I recently had to struggle with removing mine and I know how much fun it is laying under there with no room to maneuver.

Thats a great tip for pulling the the brake rod off the lever.