that's a bit wierd, sure the master isn't screwed??
Ok so my KE has an R33 master with stock KE booster, Nissan 4 pot calipers front and Bluebird single pot rear calipers.
i have bled the system so many times, so many different ways, and it just wont come good.
the peddle is quite soft, then when you pump it up it firms right up, and if you leave it for 10 sec it goes soft again... this is all with motor off BTW.
no leaks in the sys, when u pump it up then peddle goes firm and hold the peddle down it does not sink to the floor. checked that already.
so im kinda stumped...
that's a bit wierd, sure the master isn't screwed??
Im not sure what you have already tried but try these
make sure you bleed at the master cyl pipes aswell.
make sure calipers are on the correct side because if they are wrong the bleeder will be at the bottom and they will never bleed up.
get a pair of those yellow plastic hose clamping pliers and when the pedal is firm clamp the rubber hose that splits to the rear calipers(near diff) this will cut off the rear brakes so if the pedal still drops problem must be in front
then clamp off each front hose one at a time until u isolate the problem
if the pedal still drops with all the hoses clamped you either have a huge air lock some where or the master cyl is no good.
thanks that gives me something to go with.
yeah, i would try bench bleeding the master cylinder first (just bleed it from the lines if its still in the car)
then follow as buster says, clamping the rear circuit will eliminate it or show it as a problem area.
when you crack the bleed nipple, does air still come out? if there is no more air in the system then there must be something else going on.
i did have a similar problem on an ae71 van. the brake mechanic at work suggested that the rod inside the booster was the incorrect length and on some master/booster combos there is a small rubber bung that goes on the end of the rod and into the piston on the back of the master.
if this is missing, everytime you apply the brakes it needs to take up the slack first before the actual hydraulic action starts.
i unbolted the master and slid it foward (with the lines still attatched) and rotated the rod a few times, this unwound it abit and took up some of that freeplay. the pedal was better, but it really needed "the mystical bung"
maybe this is something to try, the r33 master might just be creating a gap??
I've heard of the mystical bung as well and advised Simon of such things. I need to check mine too, i am having the same problem and think that it was somewhere between when i removed the master, if i touched the brake pedal, did the mystical bung in the booster dislodge..
slide86, now theres a thought.... i reckon i have something that i could use as a spacer between the rod and the master piston... i'll give it a go today and report back
ok crimped the rear rubber line at the diff, now peddle is rock solid. So im guessing the rear calipers are the problem here?