Seized and rounded bleed nipple

[Frogmella]

While changing the flexible hoses I discovered the offside front bleed nipple is seized and already rounded off (before I got there) to boot.



I've applied penetrating fluid over a couple of days (mixture of ATF and Acetone). Long sockets are no use because the rounding is narrower than the nipple end. I've been using mole grips to try and rock it backwards and forwards to break the rust but all that is happening is that more metal is being ground off the sides of the nipple, it hasn't moved at all. I have tried hammering the tip (gently) to try and vibrate the rust grip but to no avail.


A neighbour suggested applying heat, what do you guys think of that idea?


I'm thinking I might need to source another front caliper.


Any helpful suggestions would be greatly appreciated.


Thanks in advance guys, as always.


p.s. On the nearside, the brake pipe union nut is rounded too. I'll probably just cut it off and replace the whole pipe.

[trikey]

Do what your neighbour suggested, get plenty of heat in there.

[Mike Noc]

I have a very small monkey wrench that bites into seized nipples - will be replacing all of mine as one has seized so I'll be using it in a day or two.


Plenty of heat just on the nipple can help loosen it as it will try and expand and break the rust on the threads. Then let it cool down, and spray some freezing penetrant on it and that will help it contract a bit.

[Frogmella]

I just checked the rear calipers and once again, the offside bleed nipple is rounded. What a nightmare. I was thinking I'd get all those flexible brake hoses replaced in about an hour. Silly, silly boy.

[Frogmella]

THANKS EVERYONE!!!!! The forum saved my bacon AGAIN!!!!

[Thunderbolt]

I am a bit late here, but I have had great success with Crack-It freeze spray, which is available from Screwfix.
Either just use this, or heat then rapid cool, in cycles.

My experience is mostly it is corrosion.
I have also had issues with Stainless bleed nipples where galvanic corrosion has seized them in.

[T-Cut]

The last time I removed my nipples I used two or three lturns of PTFE thread tape on them before refitting. That was several years ago now and I haven't yet ventured to see if it did any good.



TC

[Frogmella]

Originally Posted by marinabrian

You have hit the nail on the head there John, the loss or displacement of the rubber caps allow water to enter the middle of the nipple and cause the internal corrosion that makes the nipples so hard to remove.


Brian

In a first for my car, all the rubber caps are actually present and in good condition. Everywhere else, fixings, clips, bolts and screws have been either broken, seized or entirely absent.

[Fred Byrne]

You have one of my worst nightmares. The sure fire way is to heat the nipple and surrounding area red hot. This cause the rust to decompose but you must allow it to cool before undoing it. The downside is that you may destroy the seals. You could try this. Take a drill bit very slightly larger than the bore of the nipple. Drill carefully down the bore and stop before reaching the bottom. Leave the drill bit in situ and try using a visegrips or a plumber's wrench to undo it. You can grip the nipple very tughtly as the drill bit reinforces the nipple. Good Luck

Fred

[Blink]

Originally Posted by Frogmella

In a first for my car, all the rubber caps are actually present ....

Those things are £3.36 each from Rimmers - https://rimmerbros.com/Item--i-SEX100020.

Or £1.78 for eight from China - https://www.ebay.co.uk/p/23029962282...iABEgKdu_D_BwE.

The Rimmers ones do have that extra flat bit though.