Any suggestions as to getting this out? Steel nipple; cast-iron caliper. Seized in solid and as always, soaking with Plus Gas prior to removal was no help at all. I've never had any luck with these so-called 'penetrating oils' - they all suck.
I once got one out by tapping in the tang of a small square section file I have, and twisting. But judging by similar experiences, I'd suggest that I had been very lucky on that occasion. I had a set of reverse-threaded extractors, and all I ever managed to do was snap bits of them off in various things.
When I had a similar problem with a seized brake bleed nipple I had to leave it a couple of days with a couple of applications of oil before I could free it.
Actually, I don't know why I mentioned that it was square in section. Just caught up in the memory, I suppose :-)
Local engineering works. Left handed drill bit. EZ out. Calliper refurb company.
I can't say I've never snapped one, but the best way I've found to get them undone is to use a deep six-point socket, and fractionally tighten it first.
If penetrating oil could find its own way in to the thread, how come brake fluid doesn't come out? It's a waste of time, except to lubricate an exposed thread prior to undoing something.
Chris
Every tang I've ever seen has been. It's actually close to an optimum geometry for this sort of purpose.
For which there are *far* cheaper alternatives. The mark-up on petro- chemical derived products is astronomical and as you say, they don't even work half the time at least.
No, I mean the body of the file itself is square. Makes no difference :-)
Oh. Why mention it, then? ;->
That's why I replied to my own post - to wonder why I mentioned it in the first place, and to emphasise (if it was necessary, which I doubt) to the OP that the file shape doesn't matter :-)
It's actually quite a neat idea, though, to use the tang as an improvised easy-out (probably better than a real easy-out if the truth be told - they're so brittle).
It's the only time anything like that has ever worked for me.
The brake fluid seal is the cone-in-hole geometry at the bottom. The seizure is caused by moisture making its way down the thread clearance from the outside, and causing rust which expands to fill up the clearance. Penetrating oil makes its way down through the slightly porous rust, in time. Say a couple of days soaking. It then reduces the friction, giving a better chance of unscrewing. A decent amount of heat is the other thing which can work, the differential expansion cracks some of the more solid deposits.
I agree about the deep six point socket. Or if someone has already butchered the threads, then a mole wrench. (And you can use that before cutting the pipe).
The threads don't seal, the end of the nipple and the seat in the caliper/cylinder are conical - the seal is a circular, metal to metal contact. In fact the first 3 or 4 threads often (always?) have a groove cut through them to make it easy for brake fluid to bypass them before entering the centre of the nipple for bleeding.
SteveW
The best thing for seized bolts is heat (followed by plus gas followed by more heat etc) with a bit of shocking/hammering for good measure.
If you have a welder try (assuming it's snapped flush) welding a nut on. If not prob worth a go with file tang etc, WITH a decent amount of heat.
Failing that it's drilling it out, but difficult to do without damaging the original threads. Really needs mounting on a pillar drill if not a milling machine.
Why not just replace the caliper?
If that fails, replace the car ...
Sacrilege! This is a proper DIY group.
(Proud of being a bodger, only sorry that an angle grinder is not much help here, unless I suppose you are cleaning off the end of a sheared nipple prior to welding on a nut).
+1 in spades, although I would always start off with plus gas prior to removal of pistons to allow decent application of heat.
Best bet is to get as much heat differential and thermal shock as possible. This is trickier if you only have a butane blowtorch; there's nothing better than oxy-acetyline IMV but only pro workshops have it. So use a butane torch (two if possible) to heat the iron surrounding the nipple. Once you've got it as hot as you can, turn off the torch(s) and squirt Arctic spray directly into the hole in the snapped-off nipple. That should do it. Never fails for me, anyway. The key thing is the temp differential and though you won't get it optimally hot with just a blowtorch, you can make up for that by using freezy-spray on the nip instead of mere cold water or oil. By doing this you will achieve the same thermal shock as a pro shop does (and maybe more).
It's like you're constantly buying penetrating oil?
One can can last a lifetime.
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