New screw snapped inside master cylinder

[sgtBerbatov]

I bought a rebuild kit for the master cylinder of my Toyota Corolla, and everything went fine until I replaced the screw that sits at the bottom of the master cylinder. It just snapped in half, no resistance at all. Now the head is on my desk and the rest of it is stuck in the cylinder.

I'm tempted to drill it out, but obviously wary of the swarf that'll be generated from it. For those of you who have had this happen to you, is it acceptable to just drill it out, put a new thread in and use the old copper screw that was there before? Don't particularly want to buy a new master cylinder, as they seem to be hard to come by.

[stevieturbo]

Perhaps if you posted a photo of exactly what you're talking about.

But no it is not normal for people to snap screws or bolts off in something like a master cylinder. And if you managed that....surely even you would think it's even higher risk targeting it with a drill ?

[Oldandslow]

Well, if you do nothing the option is a new cylinder so you lose nothing by trying.

Did the bolt bottom out and you kept tightening?

Use a drill smaller than the bolt so you don't damage the threads. If you don't drill all the way through it'll keep swarf outside of the cylinder too. If you're lucky and the bolt being new just reverse the drill direction and it my work loose otherwise try an "easy out"/screw extractor.

[sgtBerbatov]

Oldandslow said:

Well, if you do nothing the option is a new cylinder so you lose nothing by trying.

Did the bolt bottom out and you kept tightening?

Use a drill smaller than the bolt so you don't damage the threads. If you don't drill all the way through it'll keep swarf outside of the cylinder too. If you're lucky and the bolt being new just reverse the drill direction and it my work loose otherwise try an "easy out"/screw extractor.

I've not had chance to take a photo of this, but I found a Haynes manual about the Braking system and the bolt I broke was the "Piston Stop Bolt".

What happened was I was tightening it with my hand and I screwed it down until it more or less touched the washer. Thats when I took the spanner, and it wasn't even a quarter turn and the head came clean off. The head came off and the rest of the bolt is now stuck there, slightly dipped so I would only be able to drill it out.

You're completely right, I've nothing to lose out really so I'll give it a blast tomorrow before dealing with the in laws all day. One of the two has to be less stressful!

[sgtBerbatov]

Right so I drilled the bolt out, wasn't a great success. Whatever happened the hole where the screw was got fouled by the drill. So the piston was sticking on it. Not good enough or safe enough to put back on the car, so I'm ordering a new cylinder.