Re: how du u bleed disc brake ?
Posted: Fri Feb 19, 2010 5:21 pm
the diameter of the piston on the master cylinder can have a big inflluence on the amount of travel in the lever.the smaller the diameter the more travel .
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Last 3 or 4 times I've done it, I've done this, more or less. If you have a decent size syringe then you can fill the whole system from one filling of the syringe but make sure the bottle of fluid has been sat still overnight ie no bubbles in.JOHNNY wrote: ............... take the top off the master , go get a big syringe a short length of pipe to fit the bleed nipple , put a ring spanner on the nipple then the hose , open the nipple then push the fluid back up the system it'll work its way up and fill the master , close the nipple off unclip syringe empty the master then repeat a couple of times job done , very quick and easy , ...............
Thats the method i use as well after some dealer advised me to fill from the top a few years ago and keep pumping till it gets hard !!!!!!!!!storkfoot wrote:Last 3 or 4 times I've done it, I've done this, more or less. If you have a decent size syringe then you can fill the whole system from one filling of the syringe but make sure the bottle of fluid has been sat still overnight ie no bubbles in.JOHNNY wrote: ............... take the top off the master , go get a big syringe a short length of pipe to fit the bleed nipple , put a ring spanner on the nipple then the hose , open the nipple then push the fluid back up the system it'll work its way up and fill the master , close the nipple off unclip syringe empty the master then repeat a couple of times job done , very quick and easy , ...............
First attach the pipe to the end of the syringe and open the nipple on the caliper (keep your ring spanner on the nipple, you'll need it in a minute)
Then, fill the syringe gently and slowly. When it's full, tip it back and take it over to the caliper. Then depress the plunger in the syringe and get the fluid just to the end of the pipe. Place the pipe over the nipple and, again, gently and slowly, press the plunger and fill the system until the fluid in the master cylinder is almost covering the sight hole (this does depend on the angle your handlebars are positioned).
Now's the slightly tricky bit. Close the nipple with the ring spanner. Then, keeping your left hand on the brake lever, and your right hand on the ring spanner, you need to pull the brake lever in gently a few times, at the same time as opening the nipple and pushing a little bit of the fluid out. You should feel the lever becoming harder to pull in until it's right.
Like anything, it takes a bit of practice but when you've done it once, it's dead easy
gpsteve wrote:i have just fitted new brake and bleed whith syringe how much travel sould i have at the brake lever, as brakes start to bite about half way but i can pull leaver all the way to the handel bars is this right