OK before my brakes would gradually build up pressure and lock. The push rod on the master was too long, adjusted, fixed...ah life is good.

Now on to dana 60s, the front are 3/4 ton brakes with chevy calipers and the rear is the stock drums for now. Trying to get them to pressure up for a quick dirt road run with the club this weekend, and I can't get them to pressure up AT ALL. I have bench bled the master 4 times, and bled the entire system 4 times as well. Rear is adjust properly. Seems there is no air in the lines........argh....I'm so pissed I was throwing stuff in the garage last night :mad:

advice??? anyone???


Side note, anyone know where I can get new residual valves for this master cylinder?
http://www.pirate4x4.com/forum/attachment.php?attachmentid=164417&stc=1

I have picked residual valves out of toyota cars at pick n pull. Infact, got a few for the higher psi for drums, a couple for the disc)lower psi., and a few that have no residual at all.

Are you moving enough fluid with that master cylinder? that looks to be a cruiser master(7/8") bore and might simply not move enough fluid to get the brakes to work. arent most GM masters nearly 1 & 1/16" bore? thats ALOT of fluid more than the stock toyota 7/8"

Might try pick and pull again and look at a later truck/4runner for a 1" bore master.

other issues I would check: drum brakes in rear adjusted? The way a master works most effectively depends on both circuits functioning properly, so make sure the rear brakes are nearly dragging.

Cool, thanks for the tips. The brakes were working with the 1/2 ton crap before, the front calipers are the same, the only thing different is the rear drums. Which I checked and adjusted again last night.

Usually a master will pressure up as long as the front are good. If you didnt change anything in the front then there's got to be something else.

Have you watched the rear without drums on it to make sure the slave is working? Are the fronts even slowing down the disk?

Sometimes letting is sit over night helps let bubles float to the top. You never know.

I have another vote for getting a larger master.

Seems like the master isn't developing pressure. See if it is leaking back into the reservoir internally. Pop the cap off and have someone pump the pedal. If you see fluid squirting back into the reservoir on the down stroke, it is leaking.

something else to try is pinching off the brake hoses with vise grips and seeing if it builds pressure. if it does then remove the vise grips one at a time to see which wheel is the problem... if you remove the rear and lose the pedal then its the rear. if its the left front etc.. that way you can isolate which wheel the problem is on... if the front and rear hoses are pinched off and nothing then you may have lost the master cylinder.. if the fluid was dirty or the master old sometimes they dont like being run all the way down in their bore (like when bleeding) the rubber cups run through all the crap that settles in the master cylinder bore and it breaks the seal the cups had with the bore. then when you lift the pedal to pump it again it just drags all the junk back up into the master and itll never build pressure again. ive had this happen many times on the hondas that come in for service.. cust drives in with 120,000 miles and gets a major service. flush the brake system and no pedal.. call cust and tell them that the car they drove in that morning dosent have any brakes and its gonna cost em an additional $400.00 p/l to drive their car home... :mad3: they usually dont take it very well... good luck



chris :cool2:

Could it be that you are asking for to much fluid to the front callipers. The master will push about the same fluid volume front and rear in a dual mster like you are running and the rears will work fiine but because thay are aplied,but you wont have filled the fronts with enough fluid. Or you're master is just to small.