could this be why the pressure wont build up or am I missing something ? suggestions please, of a constructive nature, thanks 
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Bleeding Brakes
Moderators: KeithZ1R, chrisu, paul doran, Taffus
Bleeding Brakes
Hi can anyone help, put the brakes on my z250 project, all cleaned up new brake caliper seals and covers, new pads, new new cylinder diaphrams, come to fill with oil, pump the levers, wont go hard to allow the bleed nipple to open and draw air off! the pipes are fresh and empty, did not change the pistons could this be why the pressure wont build up or am I missing something ? suggestions please, of a constructive nature, thanks
could this be why the pressure wont build up or am I missing something ? suggestions please, of a constructive nature, thanks CB125 GT380 CB750F1 Z1R GPZ 750 Turbo Z1R
If you are using an old master cylinder check for two holes in the bottom of it. If you have two they must both be clear - on the big zeds one hole is a tiny bore and blocks easily.
Use thin guitar string or similar (needle is too thick) to make sure it is not obstructed. Also make sure any new inner seals were fitted correct way round and have not gone wonky as they went in.
Then if still probs prime the master cylinder by pouring fluid and working until it starts to come out with no pipe connected - soon as it does connect the top pipe and wash any stray drops of fluid off.
Repeat with top pipe and brake union connected and have a container to catch fluid. Once it's coming out of the union you can connect up your calipers and hoses (try connecting a side at a time if it won't bleed two calipers at one time) and it should start to build some pressure.
Once you have the whole system connected and primed you should get a few tiny bubbles out of one hole in your master cylinder as you release the brake stroke. That's how air locks can escape and allows excess pressure to be discharged so seals don't blow out (voice of experience here I am afraid!!)
Hope this helps from Mark
Use thin guitar string or similar (needle is too thick) to make sure it is not obstructed. Also make sure any new inner seals were fitted correct way round and have not gone wonky as they went in.
Then if still probs prime the master cylinder by pouring fluid and working until it starts to come out with no pipe connected - soon as it does connect the top pipe and wash any stray drops of fluid off.
Repeat with top pipe and brake union connected and have a container to catch fluid. Once it's coming out of the union you can connect up your calipers and hoses (try connecting a side at a time if it won't bleed two calipers at one time) and it should start to build some pressure.
Once you have the whole system connected and primed you should get a few tiny bubbles out of one hole in your master cylinder as you release the brake stroke. That's how air locks can escape and allows excess pressure to be discharged so seals don't blow out (voice of experience here I am afraid!!)
Hope this helps from Mark
DavidZ1R wrote:Problem solved, tied up overnight, no joy, thanks again piggy, used a syringe to suck the oil through, worked a treat
its the way to do it david ! works every time
Keith
You can never have too many tools in your life, except the two legged variety
I'm never wrong, once I thought I was but I was
mistaken.
Phil Churchett winner 2013
You can never have too many tools in your life, except the two legged variety
I'm never wrong, once I thought I was but I was
mistaken.
Phil Churchett winner 2013
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