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Bleeding Brakes

Posted: 15 May 2011, 09:45
by Realize
Hi all

I am still having trouble with the brake pedal not feel right on my 81 air cooled T25

I think that there is still air hding inside the pipes somewhere.

I think that the guy helping me bleed them mentioned he could not undo the top nipples on the calipers and was using the bottom nipples to bleed from.

Now having searched the forum I think I read somewhere that air can be trapped in the top of the caliper and will not be expelled from the lower nipple.

Is that a possibility, just dawned on me that it may be the cause of the problem.

As the top nipples are so rounded off it is not possible to remove them, could I remove the caliper and invert it while bleeding to get the air out or am I
clutching at straws.

Cheers for any advice. Jay

Re: Bleeding Brakes

Posted: 15 May 2011, 10:17
by Ian Hulley
Realize wrote: Is that a possibility, just dawned on me that it may be the cause of the problem.

No it's a certainty.

Re: Bleeding Brakes

Posted: 15 May 2011, 10:33
by toomanytoys
You really need to get those nipples replaced so it can be bled properly...

Re: Bleeding Brakes

Posted: 15 May 2011, 11:19
by Realize
Cheers guys

Thought that might have been the case thanks for confirming it. So what special tricks can I employ to remove manky rounded off nipples (sounds painful).

Cheers Jay

Re: Bleeding Brakes

Posted: 15 May 2011, 14:22
by kevtherev
NO tricks just patience.
try heat
try plus gas soaking for a week
weld a nut to them

finaly drill ... and clean the thread out

Re: Bleeding Brakes

Posted: 15 May 2011, 18:17
by California Dreamin
Realize wrote:As the top nipples are so rounded off it is not possible to remove them, could I remove the caliper and invert it while bleeding to get the air out or am I
clutching at straws

You really should be replacing those bleed nipples BUT.......it is perfectly feasable to bleed the calipers upside down as suggested but make sure you put something between the pads so the pistons don't pop out...a piece of wood perhaps and the bleed points need to be held uppermost to ensure that air is indeed all expelled.

Shut off nut/bleed point when your helper has the pedal held down.

Long term though these nipples should be replaced.

Martin