Penetrating oil

phoenix · 10 Apr 2009, 09:04 (Ref:2437929)

I have a brass bleed nipple seized in an aluminium caliper.

What is the best performing penetrating oil for these two metals?

Thanks

Martin

bdwoody · 10 Apr 2009, 09:54 (Ref:2437952)

i would remove the item from the car first then heat up the caliper with a blow torch (carefully) around the nipple and then ease it undone and retighten and then undo some more .dont just wrench it undone coz it will snap off . if it wont move warm some more, spray wd-40 / werth or some such around the tread and let it soak in a bit but dont let the caliper cool right down. hope this helps ...

phoenix · 10 Apr 2009, 10:51 (Ref:2437983)

Quote:

Originally Posted by bdwoody

i would remove the item from the car first then heat up the caliper with a blow torch (carefully) around the nipple and then ease it undone and retighten and then undo some more .dont just wrench it undone coz it will snap off . if it wont move warm some more, spray wd-40 / werth or some such around the tread and let it soak in a bit but dont let the caliper cool right down. hope this helps ...

Hi. The item is off the car - and I stopped applying brute force before any damage to the nipple.

Before applying heat to the caliper, should I remove the pistons and seals first?

Peter Dunne · 10 Apr 2009, 13:39 (Ref:2438065)

Quote:

Originally Posted by phoenix

Hi. The item is off the car - and I stopped applying brute force before any damage to the nipple.

Before applying heat to the caliper, should I remove the pistons and seals first?

If it was me, I'd strip the caliper (to be safe) and put in new seals anyway as you have it off the car.

Dave Brand · 10 Apr 2009, 14:27 (Ref:2438090)

One of the best penetrating oils available is PlusGas. Forget WD40!

phoenix · 10 Apr 2009, 14:27 (Ref:2438091)

Quote:

Originally Posted by Peter Dunne

If it was me, I'd strip the caliper (to be safe) and put in new seals anyway as you have it off the car.

Thanks for the tip - but what about a penetrating oil?

phoenix · 10 Apr 2009, 14:30 (Ref:2438092)

Quote:

Originally Posted by Dave Brand

One of the best penetrating oils available is PlusGas. Forget WD40!

Yes - I agree - WD40 is not much could as a 'releasing' fluid. Might try Plus Gas - any other suggestions? What are your experiences of other brands - I believe the makers of Gunk do one for example. What do 'the trade' use? I'm thinking exhaust fitters here - because exhausts are always a swine to remove.

zefarelly · 10 Apr 2009, 15:15 (Ref:2438119)

if corrosion is the cause you could do worse than coca cola . . . . but don't leave it indefinitely or there'll be nothing left . . . . . shame that doesn't happen to some of the people that drink it!

diesel is another good penetrator . . .

phoenix · 10 Apr 2009, 16:23 (Ref:2438148)

Thanks Zef - I'll try the diesel first, as I have a drop of that

GORDON STREETER · 10 Apr 2009, 17:42 (Ref:2438198)

Just to stick my oar in ! I have personally found that no penetrating oil works (until the thing in question starts to move) especially if the thing is rusted or corroded up. The trick with bleed nipples and bolts seized in aluminium is to heat the offending steel part on the end until its red hot and then wait a short while to let the heat creep in to the thread and try moving it both ways. This normally works but the alloy thread can pick up. If it does at least you can normally get the bolt or nipple out and re thread it with a larger bolt or nipple, or better still repair it with an insert. Steel in aluminium is terrible for corrosion especially if not touched for years without any anti seize compound like Copperslip applied. IMHO most people over tighten bleed nipples that cause the problem in the first place !

phoenix · 10 Apr 2009, 18:59 (Ref:2438243)

Quote:

Originally Posted by GORDON STREETER

Steel in aluminium is terrible for corrosion especially if not touched for years without any anti seize compound like Copperslip applied. IMHO most people over tighten bleed nipples that cause the problem in the first place !

Your tuppence is more than welcome.

The nipples are brass, which is supposed not to 'react' with alloy like steel does, but as I understand it there is not much you can do to stop the ally oxidising on it's own. So, it isn't rust we are dealing with here.

It is certain that the nipple was overtightened and I'm pretty annoyed about that - but one out of eight isn't so bad though!

I don't think I should heat the brass nipple though as it will expand and make things even tighter, won't it? I'd rather avoid using heat altogether if I can....

GORDON STREETER · 10 Apr 2009, 19:10 (Ref:2438248)

phoenix , Sorry I didn't realise that they were brass, but heating will still help but obviously not too much. If you have the caliper off try warming it rather than the nipple as the coefficient of linear expansion might just be enough.

phoenix · 10 Apr 2009, 19:43 (Ref:2438277)

Quote:

Originally Posted by GORDON STREETER

phoenix , Sorry I didn't realise that they were brass, but heating will still help but obviously not too much. If you have the caliper off try warming it rather than the nipple as the coefficient of linear expansion might just be enough.

Which has the highest rate of expansion, do you know? Aluminium alloy or brass (also an alloy! Copper and tin, isn't it?)

GORDON STREETER · 10 Apr 2009, 22:24 (Ref:2438335)

As I'm no metallurgist I wouldn't know, but what bdwoody and I have said is that this is the only thing that we know that can sometimes work. The heat cycle when in use for brakes (up to 1000 deg) may well have something to do with bleed nipples seizing in the first place, especially in alloy calipers.

phoenix · 11 Apr 2009, 01:47 (Ref:2438402)

Looks like aluminium expands at a greater rate than brass, and then stainless steel and at an even lesser rate ordinary steel.

So, heating the caliper should help. And maybe going for stainless steel nipples (ooh, missus!) might be the answer for the longer term, as they are tougher than brass and, I guess, shouldn't corrode even next to aluminium.

zefarelly · 11 Apr 2009, 07:26 (Ref:2438446)

stainless and ally do not mix well, as any yatchsman.

your best bet is probably normal mils steel ones, and a bit of copperslip on the thread maybe.

Having just restored some 40+ year old wheel cylinders which are ally/steel they can normally be saved, new nipples are easy to get

I agree with Gordon, you shouldn't need a 4' breaker bar to loosen them off!

JohnD · 11 Apr 2009, 10:36 (Ref:2438513)

Loctite "Freeze & Release" spray is supposed to release seized parts. I have to say that it hasn't worked for me, but it does get the part VERY cold. After heating the alloy caliper, you might try an accurate spray of the stuff onto the nipple - expanded caliper, contracted nipple.
Stop sniggering at the back!

John

phoenix · 11 Apr 2009, 10:36 (Ref:2438515)

Quote:

Originally Posted by zefarelly

I agree with Gordon, you shouldn't need a 4' breaker bar to loosen them off!

Only if a gorilla use a 4' breaker bar to tighten them in the first place.....

phoenix · 11 Apr 2009, 10:38 (Ref:2438516)

Quote:

Originally Posted by JohnD

After heating the alloy caliper, you might try an accurate spray of the stuff onto the nipple - expanded caliper, contracted nipple.
Stop sniggering at the back!
John

I'll video it...

GORDON STREETER · 11 Apr 2009, 11:47 (Ref:2438543)

If you have the caliper off, put the nipple in a bench vice and heat up the caliper. This will tend to keep the nipple colder whilst you can twist the caliper back and forth with a pair of gloves. also you will have more control.
I wonder if Max Mosley has tried this one

phoenix · 11 Apr 2009, 12:43 (Ref:2438558)

Quote:

Originally Posted by GORDON STREETER

If you have the caliper off, put the nipple in a bench vice and heat up the caliper. This will tend to keep the nipple colder whilst you can twist the caliper back and forth with a pair of gloves. also you will have more control.
I wonder if Max Mosley has tried this one

Is there anything he hasn't? Still, I guess we won't be reading about it anywhere if he has!

coln72 · 11 Apr 2009, 13:18 (Ref:2438567)

While I havn't used it in your application, I have found Wurth's "Rost Off" ok. Much better than WD40 etc. In fact, my old man ran a mechanical workshop servicing a fleet of fire trucks swore by it and some of those things were pushing 25 years old.

thebear · 11 Apr 2009, 22:09 (Ref:2439026)

After reading some of the comments I believe it is appropriate to mention that WD-40 is intended as a water displacement material.

Here is some HISTORY and here is the company's WEBSITE. .

JohnD · 12 Apr 2009, 09:58 (Ref:2439179)

Indeed, it's not a good lubricant.
WD40 is billed as having 2000 uses, from easing arthritic joints (Highly dubious. See: http://www.peoplespharmacy.com/archi...iff_joints.php) to making public toilets unusable for snorting cocaine (Yes! Really! See:http://www.cocaine-addiction.co.uk/index.php?p=21&c=1) One I'm fond of is that is will stop a worn fan belt from squeaking, but won't make it slip.

John

phoenix · 12 Apr 2009, 10:14 (Ref:2439184)

Quote:

Originally Posted by JohnD

One I'm fond of is that is will stop a worn fan belt from squeaking, but won't make it slip.

John

Is that true, or false?

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