80yotaman

I just recently did the rear disc brake conversion. I went with a new 1" bore MC, bled all the brakes with no air in the lines. But i still have to pump the brakes when im wheeling to get it to stop. A buddy of mine said the booster could be bad? Shoot me some ideas.........

justin_4runner

try re-bleeding the brakes with the truck running, and make sure u do them in the order that the fsm calls for,

cruisertom

Is the MC you used for 4wheel disk brakes? Did you bench bleed the MC before you installed it? Do you have an adjustable pressure valve for the rear circuit? Some more info might help and keep in mind that any mod to the system will change how everything works, like different calipers in front and adding to the rear and changing the master cylinder.

dropzone

iTrader: (6)

you bled RR, LF, RF, LF? in that order furthest to closest?
what proportioning valve did you use in the back?
some say you are fine with the LSPV (did you bleed that if you still have it?)
personally I am going to be using the kit from Front Range:

it will be mounted on the MC
kits like the one from Dave's off road are mounted back in place of the LSPV"


Did you bench bleed the MC prior to installing it?

James Woods

iTrader: (1)

Usually from my experience, if the booster is bad then you get a very stiff pedal. If you try all that was stated above, I have found with brake swaps that sometimes it seems as though all the air is out but still feels squishy, gravity bleeding each caliper for a bit has always helped me with this issue.

80yotaman

I just put all new brakes master cylinder rear disc brakes and rotors. Bled lines with no air. Still have to pump brakes to have to stop. What the deal Idk. Im stuck. Any suggestions?

justin_4runner

there a pita to bleed the brakes, after doing my master and a caliper i was able to get my brakes by doing them in order that fsm calls for and with the truck running and used a one man bleeder kit... did 3 pumps on each one and ended up with a nice brake pedal

80yotaman

Could the brake booster be bad?

waskillywabbit

iTrader: (-1)

Folks have asked you specifics and you've ignored them. Did you bench bleed the MC? What about the LSPV? Sounds to me like air still in the lines.

:wabbit2:

80yotaman

I've never heard of bench bleeding a MC. The LSPV valve is still on it. I've bled 2 quarts of brake fluid too.

waskillywabbit

iTrader: (-1)

You still have air in the lines if you didn't bench bleed the MC and if you didn't bleed the LSPV just like the calipers.

See ocdropzones post above.

:wabbit2:

SCToy

It's actually rear left, rear right. If you follow the brake lines on the axle the left side is longer. At least on a 3rd gen pickup.

80yotaman

Sorry for all the confusion. Thanks for the tips ill try what y'all said and ill let ya know how it does

cruisertom

If you don't bench bleed the master you can still have air no matter how many quarts you run through it. Also if the reservoir goes dry after you bench bleed it or while bleeding the system, you will have to start over.

cruisertom

After you have properly bled the system and still have issues, you will need to check the gap between the booster push rod and the cylinder. You will need a special guage that looks like an H with a rod in the center that is a guage to measure the depth of the rod sticking out of the booster then you turn it around and measure the depth of contact in the cylinder. If there is too much gap or the rod slightly pushes in on the cylinder with no pedal pressure you will have break problems. You should do this before it goes in the car and bled, however it can be done now it is just a PITA.

66stoutsbc

What did you find