brake bleed nipple: sheared off
Stephen
I read and read the threads here about brake fluid changes to
familiarise myself and I read that corroded bleed nipples might shear
and unfortunately, the same thing has happened to me.
It's the one on the front so it's on the caliper of a disc, rather
than on a drum, not that I expect that makes any difference. It's a
Citroen C3 but I doubt that makes any difference either.
Not only has the top sheared off but it seems to have sheared below
the surface of the caliper, so I cannot grab the remnant with mole
grips or anything like that.
I would think it would have to be drilled out. I know there are
left-handed screw removers but when I have read about those on the
'net, reviews always seem to be uncomplimentary. I'm worried they may
do more harm than good.
Is there anything I can do, or is it best to take it to a garage now?
What would they do? Would they attempt to remove the broken part or
would they just fit a new caliper?
Am I able to drive to the garage or should I be towed? There is a
Gunson easy bleed on it pushing with 20psi and I would have thought
that if I had managed to turn the nipple, by now my drive would be
covered in fluid and the reservoir would be empty but nothing has
happened. I think I managed to turn the top of the nipple but not the
bottom! Does this mean that the remnant is still tight and the car is
safe to drive?
Thanks.
Mrcheerful
"Stephen" <ste...@nowhere.com.invalid> wrote in message
news:l79346h23fpnvi4kb...@4ax.com...
if it doesn't leak when you press the brake pedal (engine running) then it
is quite safe to drive.
very few garages have any engineering skills these days, almost every one
will just fit a new pair of calipers (which are very cheap in any case now)
removal of the broken bit would likely require removal and dismantling of
the caliper, careful drilling down the bore of the broken bit (without
breaking through) insertion of a grooved screw extractor (not a taper one)
heating of the area and hopefully it would undo. rebuild the caliper and
bob's etc. trouble is that the average place would have to charge more
labour than a new caliper.
Rob Graham
I have sheared nipples on both front wheels and have had for some years.
If I need to bleed the brakes I just slacken the union of the flexipipe
into the back of the top wheel cylinder and get the air out that way.
Always works. (Drum brakes) I think whether it will work for you will
depend on how high up the union is into the caliper. Nothing lost
trying, though (just a bit of brake fluid).
But why are you doing this? If you are just trying to replace all the
fluid rather than trying to expel the air then I'm sure you'll be OK.
Rob Graham
Duncan Wood
wrote:
I've always got them out with a cordless with a left hand bit or a steep
taper tapered extractor
(http://www.powertooldirect.co.uk/dormer_m100_no1_csscrew_extracto-p-75220.html)
Mrcheerful
"Duncan Wood" <nntp...@dmx512.co.uk> wrote in message
news:op.vfz0k...@lucy.cable.virginmedia.net...
I would not recommend it as a job for someone without skills in that
direction, just in case (and if the OP was skilled he probably would not be
asking here). Depending on the vehicle the nipple thread can vary from
about 6 mm to 10mm, French stuff is usually fairly small, making the job
harder.
Stephen
<rttg...@btinternet.com> wrote:
>why are you doing this?
I was attempting to change the brake fluid because it was due a change
(hoping this won't start a fierce debate about whether it needs
changing every two years or not!).
Stephen
<nbk...@hotmail.co.uk> wrote:
>if it doesn't leak when you press the brake pedal (engine running) then it
>is quite safe to drive.
I stood on the pedal a few times with the engine off and nothing
happened. I will try with the engine on but I am sure that if it was
going to leak it would have done so by now.
>trouble is that the average place would have to charge more
>labour than a new caliper.
I see. Thanks.
Stephen
<nntp...@dmx512.co.uk> wrote:
>I've always got them out with a cordless with a left hand bit or a steep
>taper tapered extractor
>(http://www.powertooldirect.co.uk/dormer_m100_no1_csscrew_extracto-p-75220.html)
Thanks. I've never used one but when they've been mentioned here and
elsewhere on the 'net, people never say nice things about them.
Stephen
<nbk...@hotmail.co.uk> wrote:
>I would not recommend it as a job for someone without skills in that
>direction, just in case (and if the OP was skilled he probably would not be
>asking here).
If I were skilled, I wouldn't have broken it off! ;)
Mrcheerful
"Stephen" <ste...@nowhere.com.invalid> wrote in message
if the fluid gets changed every couple of years (as it should) then the
nipples don't get seized, so yes you were trying to do the right thing.
You can still change the fluid without touching the nipple. You will need
to release the caliper from its mounting bolts (having slackened the brake
hose first) then loosen the hose a bit more and press in the caliper piston,
fluid should come out of the loosened joint, keep the piston pressed in and
pump through fresh fluid, with the pedal pressed down tighten the hose,
refit the caliper and final tighten the hose, press the pedal a few times to
push the piston back out.
Duncan Wood
wrote:
Oh never bet on that :-)
Duncan Wood
wrote:
They're not guaranteed to work. If the original failed because it's rusted
in place then the bit you apply them too after you've drilled it is even
weaker. In order to stand a chance of working they're "glass hard" so if
you knock them or bend them sideways whilst using them they snap & then
they're far harder than the original bolt so drilling them out involves a
solid carbide drill, snap that (which is even easier) & it gets really
dull. Left hand drill bits are more reliable for most things, in my
experience, bleed nipples are the odd one out as the tend to have a weak
point between the threaded bit & the hex.
Grimly Curmudgeon
drugs began to take hold. I remember Stephen
<ste...@nowhere.com.invalid> saying something like:
>If I were skilled, I wouldn't have broken it off! ;)
Don't be so sure - it happens to everyone.
McKevvy
Yes it's safe to drive because you haven't actually released the
nipple - you've sheared it at the top while the bottom valve part of
the nipple has remained firmly static.
In your case the caliper will have to be replaced. Financially today
it's a false economy to take it to an engineers to have him drill it
out, re-tap it and replace the new nipple. Best thing to do is to
replace the caliper. In future - if you have the availability - the
best thing to do is put some loosening agent on it the day before you
attempt to slacken it and when you do go to slacken it heat it
surrounding part of the caliper with oxy-acetaline.
When people bleed brakes they often assume that the nipple must be
cranked on tight as buggery but it only need to go on firmly - it wont
slacken because its tapered. Doesn't stop people thinking that it need
to go on with a shipyards strength though.
McK.
Stephen
<vicko_...@hotmail.com> wrote:
>In your case the caliper will have to be replaced. Financially today
>it's a false economy to take it to an engineers to have him drill it
>out, re-tap it and replace the new nipple.
Is tapping necessary? Can't they drill it out without damaging the
existing thread?
>Best thing to do is to
>replace the caliper. In future - if you have the availability - the
>best thing to do is put some loosening agent on it the day before you
>attempt to slacken it and when you do go to slacken it heat it
>surrounding part of the caliper with oxy-acetaline.
I did put penetrating oil on but I don't think I left it on for long
enough; it certainly wasn't on for a whole day before. I thought you
couldn't use heat because it would damage seals?
>When people bleed brakes they often assume that the nipple must be
>cranked on tight as buggery but it only need to go on firmly - it wont
>slacken because its tapered. Doesn't stop people thinking that it need
>to go on with a shipyards strength though.
I guess people are scared that if the nipple is loose, brake fluid
will gush out and their brakes will fail so they over tighten. I think
my mistake was to do the opposite: us shipyard strength to undo it!
Chris Whelan
> On Sun, 25 Jul 2010 16:05:27 -0700 (PDT), McKevvy
> <vicko_...@hotmail.com> wrote:
>
>>In your case the caliper will have to be replaced. Financially today
>>it's a false economy to take it to an engineers to have him drill it
>>out, re-tap it and replace the new nipple.
>
> Is tapping necessary? Can't they drill it out without damaging the
> existing thread?
>
>>Best thing to do is to
>>replace the caliper. In future - if you have the availability - the best
>>thing to do is put some loosening agent on it the day before you attempt
>>to slacken it and when you do go to slacken it heat it surrounding part
>>of the caliper with oxy-acetaline.
>
> I did put penetrating oil on but I don't think I left it on for long
> enough; it certainly wasn't on for a whole day before. I thought you
> couldn't use heat because it would damage seals?
Penetrating oil does very little penetrating!
It's a help if you have a bolt going through a nut, and the exposed
thread id rusty, but that's about all.
With care, you can localise the heat so you don't damage the seals.
Bear in mind that in use, calipers can get bloody hot.
>>When people bleed brakes they often assume that the nipple must be
>>cranked on tight as buggery but it only need to go on firmly - it wont
>>slacken because its tapered. Doesn't stop people thinking that it need
>>to go on with a shipyards strength though.
>
> I guess people are scared that if the nipple is loose, brake fluid will
> gush out and their brakes will fail so they over tighten. I think my
> mistake was to do the opposite: us shipyard strength to undo it!
I've never broken one when tightening; undoing, yes.
I also wiped one off on a Citroen van recently whilst trying to undo the
caliper mount bolts in order to change the pads. Fuck, were they tight!
It's someones lease van with about a year left on it, so the bleed nipple
stays broken!
Chris
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