master needs spacing with the shims on the fire wall/changing rod length/adjust peddle stop
if you got pressure at master holding brakes on master is not releaving pressure
you will have huge problems bleading because not using fluid from resiviour
piston not back far enough fill port not open

good idea wards, will do

the new master has a small bolt that screws up in to the barrel, between where the brake lines screw in, any know what that is/does?

Check that the pedal is coming all the way back and that the push rod has play in the back of the master cyl piston , the piston must come all the way back to the circlip in order to expose the fill ports in the resivoir . It sounds like the push rod is too long and this could cause your hard to bleed and holding pressure issues

yeah it got the better of me today

first couple of times the rear passenger calliper was the only hot brake (walking around the car burning my finger tips off trying to figure out what was going on)

next couple of times it was both backs (and definitely not fronts)

today it was all four, i was cracking the nipples on the master to release the pressure (did it twice to get home, about 2km)

the front circuit had more pressure, but i was cracking it first so im not sure if that's why not much released from the back circuit when cracking it open second


[edit] using dot 4, lids on new master say to use dot 3 but i ignored that

is odd that you are getting the same problem front and rear as they are completely different circuits.

what brake fluid are you using? you haven't used DOT5 or something have you. as ive heard that kills normal rubber lines

so the backs blead fine and just the fronts that didnt? but all 4 are dragging?

yeah, im not really suspecting check valves here, as i'm having the same problem as before the master change

been running these brakes for about 5years+ so yeah.... im suspecting possibly a hose or that bias block on the firewall or a kinked line or ...... dunno blocked somewhere

will have a look at check valves in old master tomorrow, and look for these grooves, spring tension in front and back check valves felt very similar on new master

thats cool, i only ever ran mine with the 7/8ths. but figured there would be way to much pedal travel with that small a bore master cylinder. think i would have gone 13/16th on my landcruiser/r31 setup as the 7/8ths was a tad too hard for on the street

if you are having troubles with it grabbing then its most likely that either the rubber lines are #OOPS#ed or that the check valves are actually holding pressure

i can only speak from my own experience but like i said ive ran a disc/drum master on disc/disc setup with no troubles and had pulled a disc/drum master apart to have a look at the check valves and both had a groove down the side of them

at first seemed like one brake, rebuilt the backs and it seemed like both backs, but today with new master it seemed like all 4 holding

weird!

i had a lot of trouble bleeding the fronts, tried a lot with vacuum bleeder but it seemed to be pulling fluid really slow, then the only way i could get good firm pedal was to manually bleed the front (5 pumps then release nipple... over and over)

yeah bigger master = more force to press and less travel

i'm happy with my pedal force/feel and there is not excessive travel, to me a bigger master would just necessitate the use of a booster

i'm spewin though, i got stuck out on the road...
i have been having trouble with brakes rubbing or holding pressure, they are heating up quite quickly and locking on

it seemed like one rear caliper a couple of weeks ago, so i figured it was binding, i had the rear calipers rebuilt and discs machined

problem still there so..

i dropped it into a brake place and they checked it over and suggested it needed a new master, a put that in today and problem is still there


ANY SUGGESTIONS?

i got it home today by releasing the bleed nipple on the master, this dropped pressure out of the system and would allow me to get about 1km, did it twice on the way home.

the pedal goes extremely stiff when the problem is occuring

Small bore = higher pressure which is preferrable with no booster