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MG Midget and Sprite Technical - Best way to undo bleed nipples (SoMC)
|Hi all (Sort of midget Content)|
The girlfriend has a toyota starlet that needs its brakes bleeding, but the bleed nipples look really rusted in. What's the best way to get them out without snapping them off? I snapped some off before on a different car and rendered the whole calliper scrap :( I'd rather avoid that...
midget content here - mine will need doing soon so would rather not do the same on the midget ones!
|Other than soaking in a good penetrating oil for a few days prior to removal I like to use a 1/4" drive ratchet and socket to break them loose initially. I feel that I can get a bit more direct turning action without as much side loading as I would get with a standard box end spanner or flare wrench.|
|A couple of important things to do initially|
As stated use a hexagonal socket (6 sided) and at biggest a 3/8 th drive for the reasons Bill mentioned.
A lot of penetrating oil
Hit the nipple on its end with a blow from the hammer before attempting removal (this can help crack the rust/corrosion. Finally try to tighten the nipple a tad initially again to break any corrosion.
These things are all about feel, you should be able to judge when things aren,t going to plan and take corrective action. It is possible to significantly warm up the nipple before trying to free it without damage to the caliper if necessary. Warming the nipple will always break it loose and should be done before the nipple is broken off.
If you break the nipple off you should be able to carefully weld a spot onto the braken nipple to give some sort of grip for stylies or such like. The act of the welding will ALWAYS break the corrosive grip and allow extraction. Do not attempt to get out a broken nipple by drilling or a left handed tap/screw extractor
|Robert (Bob) Midget Turbo|
|Some will frown against use of heat here due to the fluid, but applying heat to the nipple then spraying the penetrating oil will make the oil soak down the threads much easier.|
1/4 ratchet, 6-sided socket, tap it round, dont swing on it, the shock loading is more likely to loosen the nipple than full body weight which will only cause it to shear.
|All of which is fine, unless it's an elbow nipple...|
|Fortunately it's a normal one.|
thanks a lot.
I'll try gently, then might have to get some kind of heating thingy to get them hot. I've actually got a spare calliper that's wrecked and all corroded away but has an OK nipple, so I've got one spare go at it....
someone else suggested a something in the hole to stop them collapsing in on themselves? might that be a good plan too?
Not heard that story before of pushing something down the hole, (not sure they colapse on themselves seem to either break foo or simply round the hexagon by a poor fittment of tool.
I would not refit a poor nipple but would simply go and buy a new one from any motor shop.
|Bob Turbo Midget England|
Kind of the same but also opposite of your suggestion, Peter; I've had great success on quite a number of relatively small threads with Freeze and Release. Very good a breaking that corrosion sticktion, but obviously with cold instead of heat. It also suggests on the can that you tighten the nut slightly before undoing it.
|After letting it soak in penetrating fluid for a while, as already stated, give it a few sharp taps with a hammer to loosen the rust, then try turning clockwise to tighten very slightly before turning back to unscrew.|
|Instead of hitting the nipple, take a blunt chisel and a hammer and hit the caliper around the nipple with lots of light quick blows. Do it for a couple of minutes before you even attempt to get a spanner on it. I have used this method for a lot of years and it really works well. Like an impact wrench shocks things loose.|
plan is to:
soak in fluid
bash surrounding area with something
going to try that tomorrow :)
|Keep us informed, if it does snap, you'll need to know how to get what's left out of the calliper!!!!|
|If all else fails give Andy Gray a call, he will get them out !!|
Sorry in advance for that one.
|Here's my twopenny worth . . . .|
Loctite make a Freeze and Release spray (Halfords do their own version). I have never used it, but I hear good things. Spray it directly onto the bleed nipple - the contraction of the cold metal should break the corrosion 'joint'.
When I bled my Astra's (excuse my language) brakes, the bleed nipple's flats were already chewed (by me on a previous occasion). Although corrosion wasn't the problem, I did use a miniature 'Stilson' self-locking action wrench (miniature meaning approx 4 inches in length) on the chewed flats. Easy as pie.
Always use penetrating oil, something like Plusgas. WD40 won't have the same effect.
|well it's worked. penetrating fluid, tapping and a little heat from a camping stove and off it came. |
i used a long socket, 1/4 inch drive, tapped it a bit while holding my breath.
a bit hard to bleed as the nipple appeared to be blocked, ran a small drill down it and it's OK again now.
I did have a reserve plan of taking it to work tomorrow and liquid nitrogen-ing it.
thanks a lot!
This thread was discussed between 31/01/2011 and 02/02/2011
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.