The problem is the angle of the tang isn't ideal. So will tend to spread the top of the nipple before getting a grip. A more gentle taper would make more sense.
With 'easy-outs' you do tend to get what you pay for. Some can be extremely brittle.
Depending on the cost of a new caliper, I'd be inclined to remove it, strip it down, use some heat to get the old nipple out, and re-build with new seals. Do both on the same axle together. With all new bleed nipples.
I'm one of those who've never found it to work. ;-) Heat does, though.
In message , "Dave Plowman (News)" writes
And as a result, it just sits there, unused, on the shelf. As I said, one can can last a lifetime.
Indeed. There's nothing like a bit of expansion and contraction. As has been mentioned, it's usually best to tighten things first, and then slacken. At this stage, a bit of penetrating oil could help,
If ever a solution to this problem was so badly named, then this must be it. There's nothing "easy" about them IME. About as much use as penetrating oil (i.e, none).
The problem here is that these butane blowlamps you get don't put out nearly enough heat for this idea to work. I've never known blowlamps to work, even using two at once - but I've never known oxy-acetelyne to fail.
BTW, I was in some plumbers merchants today to get some more solder and I noticed they're doing 'Propylene' gas (whatever that is). Can't say I've seen it before and maybe that has a higher calorific value than butane? Still probably not enough for the OP's purposes, though.
You will probably get enough heat using MAP/MAPP gas and something equivalent to a Surefire 2 blowtorch head.
It's not heat you want, it's temperature. See:
Is there a good reason why a new or used calliper isn't being considered?
Otherwise I've generally been successful in drilling out the offending bolt/nipple where I open out the hole until the male thread is breaking up.
At least you have a convenient centring guide.
I have. Can't remember what I did. Probably a refurb...
Doesn't it seal against the bottom of the hole, rather than the thread?
Often, yes.
You actually need to transfer enough 'heat' - ie energy in joules or calories. The more heat you can transfer, the higher will get the temperature. However, the rate at which you transfer it has to be greater than the rate at which what you're heating is dissipating it - so the bigger and hotter the flame the better. Obviously, there are limitations to both.
Chris Whelan explained :
If they are really stuck and on the point of breaking off, I have always found a gas torch with a small flame works well to free them.
Well, the fluid is sealed in by the nose of the nipple, not the thread. There is always some clearance on threads, to allow penetrating fluid to wick down.
Since they should be undone every two or three years, they should never become a problem. When I take a bleed nipple out, I power wire brush it and coat it in grease, this also helps with the bleeding process as there is little chance of any air getting back in along the threads. I cannot even remember the last time I had a bleed nipple snap off, must be 25 years or more.
MrCheerful brought next idea :
+1I only fix my own vehicles, but likewise I have not had a seized one to deal with for around 40 years. No matter what I am working on, if it can rust and seize - I grease it on assembly. It makes subsequent work so much easier.
Yeah, but IIRC you *have* to use that special red grease if you're going to do that.
Well, by the time I'd tried all of the suggestions here I ended up with just a small 'wart' sticking out about 4mm proud of the caliper casting. That was all there was to grip on. I was on the point of grinding it down flush and drilling it out as a last resort. But I thought before I did that I'd just give my old pal down the road a try to see if he could come up with an alternative. This bloke is 76 years old, used to run his own garage and is still as strong as an ox (ex-farmer's boy constitution as it happens). Firstly he tried welding a nut to the stump (which I'd already tried and failed). That just twisted off as it had with me. He tried that once more and got the same result. So he found a old bolt in his junk box and instructed me to hold it against the stump whilst he tacked it in place. So he's tacked the threaded end of the bolt to the stump and got a ring spanner to fit the head on the other end and to my utter amazement, he was able to unscrew the nipple! I honestly thought he'd lost his marbles and couldn't see how it could possibly work, but it did! It's amazing the experience these old boys have accumulated over the decades. I was just left speechless. And very, very grateful. :) Hopefully someone else reading this thread at some future time will also benefit from this advice.
Chris formulated on Friday :
No, the red grease is for smearing under the dust cover and seals. Around the bleed nipple thread you can use copperslip or just ordinary grease, providing it will not mix with the fluid or contact any seals.
Well done. Now I hope you've learnt your lesson. Next time don't snap the head off - heat shock lubricate repeat and most of the time it will undo.
As an alternative to grease/antisieze a bit of ptfe tape will stop bleed nipples seizing in future
It's all very well doing this and it does work wonderfully, but you really need oxy-acetelyne gas for the hottest flame because Butane and similar blow-lamp gas just hasn't enough ferocity to get the job done.
Yes, sounds like a good idea.
So how do we persuade manufacturers to use ptfe tape from new, please?
A standard butane blowlamp is not nearly hot enough, a propane torch is much hotter, but for most jobs (seized on nuts, things that need some warmth to come apart etc. ) I use a turbo torch with Mapp gas, which is a blend of acetylene and propane. Something big though I get out oxy-acetylene, but that is rare since I got the turbo torch, which is instant light and very convenient to hand.
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