Brake bleed nipples
Discussion
Okay, it's official, my car hates me!
I'm replacing the flexi-hoses on my car, and obviously have to remove the calipers to fit the new hoses.
Well, the bleed nipples are welded solid in the calipers, 2 have sheared so far on one caliper with very little effort!
So, my question is how best to remove the offending nipples, do AP Racing offer a rebuild service, and if so how much? I'm going to so much effort with all of this I think I'm looking at getting all 4 rebuilt and nipples replaced.
Getting Peed off with this
Everything else is going so smoothly 
Tim
I'm replacing the flexi-hoses on my car, and obviously have to remove the calipers to fit the new hoses.
Well, the bleed nipples are welded solid in the calipers, 2 have sheared so far on one caliper with very little effort!
So, my question is how best to remove the offending nipples, do AP Racing offer a rebuild service, and if so how much? I'm going to so much effort with all of this I think I'm looking at getting all 4 rebuilt and nipples replaced.
Getting Peed off with this
Everything else is going so smoothly Tim
Edited by TT Tim on Sunday 17th February 14:42
There was a thread a while back where someone had the same problem. Apparently the calliper material and the type of nipple used guarantees a reaction that corrodes them into place 
They had the calliper drilled out and a new threaded insert fitted IIRC.
Done a search but can't find the thread.
I seem to remember being told that heating up the nipple helps to crack the seal.
They had the calliper drilled out and a new threaded insert fitted IIRC.Done a search but can't find the thread.
I seem to remember being told that heating up the nipple helps to crack the seal.
This happened to me on my two rear calipers a few weeks ago. After fumbling about with various methods involving welding a nut onto the sheared nipple, and using torxs keys to shift the nipples, I eventually gave up and paid 40 quid to have the nipples drilled out and heli-coils fitted by a local engineering workshop. I probably could have done it myself, but given the risk of buggering upo my callipers, I feel that it was forty quid well spent. The only trouble is in getting a good seat at the base of the nipple once its been drilled- it just takes a lot of working the nipple back and forth to bed it in. Be sure to test it well before you set off on a hoon!
Edited by brogenville on Sunday 17th February 17:56
julian64 said:
Blowtorch, and pipefreeze, never fails.
Julian, I only applied the minimal torque and the just sheered off.Even the one I heated to red hot and then sprayed with WD40
So, only option now is to drill and rethread.
I'm doing all 8 so i know they're done. With s/s inserts I can safely use s/s bleed screws.
Tim
The WD40, I have never got to work because when the thing is hot the WD40 just boiled off.
The worse I ever encounted was the brake nipples off a Citroen Xantia. Broke one just trying to turn it. Swore a lot.
Then I heated the whole caliper up with a blowtorch. Important to just use the blowtorch on the other side of the metal in a constant place. This allows you to feel the temperature creeping through the metal rather than just feeling the surface temp. Took about 10mins constant heating to get the thing too hot to touch.
Then I put a pastic bleed tube on the nipple and sprayed pipe freeze into it for about 2 minutes, only slowly so the pipe freeze didn't go far into the caliper. (Actually I tend to cheat here cos pipe freeze is expensive and I have rather an easy route to laying my hands on liqiud nitrogen). I then practically took the nipple off with my fingers.
Is the caliper in a state where you can bring it to me?
The worse I ever encounted was the brake nipples off a Citroen Xantia. Broke one just trying to turn it. Swore a lot.
Then I heated the whole caliper up with a blowtorch. Important to just use the blowtorch on the other side of the metal in a constant place. This allows you to feel the temperature creeping through the metal rather than just feeling the surface temp. Took about 10mins constant heating to get the thing too hot to touch.
Then I put a pastic bleed tube on the nipple and sprayed pipe freeze into it for about 2 minutes, only slowly so the pipe freeze didn't go far into the caliper. (Actually I tend to cheat here cos pipe freeze is expensive and I have rather an easy route to laying my hands on liqiud nitrogen
). I then practically took the nipple off with my fingers.Is the caliper in a state where you can bring it to me?
julian64 said:
Is the caliper in a state where you can bring it to me?
2 nipples on the front n/s have sheered, the o/s front is okay as these were changed 2 yrs ago, as Austec broke one and they were spark eroded. The rear o/s has one sheered. It was at this point I started to weep and though it best to find another job to do before I broke something else. The nipples are so sort they're like plastacine.As for retapping, my idea is top replace with s/s nipples, so didn't want s/s and alloy, and thought s/s insert and s/s nipple was a better idea.
Would love to bring up the rear calipers to witness your 'technique' for future ref.
You haven't got a large pillar drill as well have you? Mine is small and i may have to 'improvise' when drilling out the broken nipples!
Thanks again
Tim
Oh yes I have a large pillar drill. Its called a mill 
.
With a soft nipple and hard alloy calliper you shouldn't need to helicoil. Drilling acurately down the centre of the nipple even half the diameter should give you an easily removable bit.
Email me when you want to come, I'm around thursday afternoon and most evenings/weekends.
No social life me
.With a soft nipple and hard alloy calliper you shouldn't need to helicoil. Drilling acurately down the centre of the nipple even half the diameter should give you an easily removable bit.
Email me when you want to come, I'm around thursday afternoon and most evenings/weekends.
No social life me
Not on a Cerb - but when my bleed nipples were seized we put a large nut over the bleed nipple and welded it on. This gave us a bit more persuasion on the nipple (oooh err) and allowed us to take them out. Saying this, if the nipple is shearing at the point where it enters the caliper your probably better off with whats already been suggested - Heat and a pentrating fluid.
^^ Mine after i welded a big nut on the bleed nipple ^^
^^ Mine after i welded a big nut on the bleed nipple ^^
http://www.jlindustrial.co.uk/CGI/INSRIT?origin=VI...
Its a bit pricey but not sure of the caliper hardness so I might have gone a bit overkill on the strength. You could risk <700nm hardness if you want which will be cheaper as you are only cleaning the thread. But this tap is the sure fire equivalent of a mallet. Its the blind end code version.
Good to chat Cerbs this afternoon with you both.
P.S.
http://www.buzzflyer.co.uk/Sub-Micro-RC-Helicopter...
However I will spit blood if you are making it do circuits before me.
Julian
Its a bit pricey but not sure of the caliper hardness so I might have gone a bit overkill on the strength. You could risk <700nm hardness if you want which will be cheaper as you are only cleaning the thread. But this tap is the sure fire equivalent of a mallet.
Its the blind end code version.Good to chat Cerbs this afternoon with you both.
P.S.
http://www.buzzflyer.co.uk/Sub-Micro-RC-Helicopter...
However I will spit blood if you are making it do circuits before me
.Julian
Hmm, sounds like sooner or later we will all be faced with how to get the bleed nipples to work. Shocking choice of materials.
TT, if you decide to go original with the tap like brummie, you may want to get a job lot of new nipples from AP for the rest of us, although thanks to your guinea pig calipers I'm still fairly confident I can get mine out without busting them.
(forever the optimist).
TT, if you decide to go original with the tap like brummie, you may want to get a job lot of new nipples from AP for the rest of us, although thanks to your guinea pig calipers I'm still fairly confident I can get mine out without busting them.
(forever the optimist). Gassing Station | Cerbera | Top of Page | What's New | My Stuff