Booster to master cylinder?

[bmrrwolfe]

I'm swapping from power drums to power discs and bought a master cylinder and proportioning valve off a 72 power disc truck, now i was told that the master cylinder will bolt onto the booster off of my 70 with power drums?
Also is there anything special i need to do for the swap?
Thanks!

[mclairmo]

Bench bleed the master really well to make sure you have no air bubbles left in it at all. Also, verify that the rod coming out of the booster is not too long or too short. If too long, it will slightly depress the piston in the master and cause your brakes to drag or lock up. If too short, your pedal will have to travel farther to engage the brakes. If the master and valve are used, make sure they are working well and not leaking. The valve sometimes gets clogged with gunk and rust.

[bmrrwolfe]

Originally Posted by mclairmo

Bench bleed the master really well to make sure you have no air bubbles left in it at all. Also, verify that the rod coming out of the booster is not too long or too short. If too long, it will slightly depress the piston in the master and cause your brakes to drag or lock up. If too short, your pedal will have to travel farther to engage the brakes. If the master and valve are used, make sure they are working well and not leaking. The valve sometimes gets clogged with gunk and rust.

This may be a dumb question, but ive never bench bled a booster before... how do i go about doing it? Im reusing the rod that was already in my booster and i think it still sits out the same length it did before with the drum master cylinder.
Also their is no seal that goes between the booster or master cylinder is there?
Thanks!

[68gmsee]

You should be able to buy a brake cylinder bleeding kit at Napa or other parts stores. Google "bleeding the master cylinder" on the net and you can see how it's done. Lots of good info.

No gasket between master cylinder and booster. MC should be sealed and booster should be also. Probably better that there isn't one so a person can detect if there's a leak in the MC...

[bmrrwolfe]

Originally Posted by 68gmsee

You should be able to buy a brake cylinder bleeding kit at Napa or other parts stores. Google "bleeding the master cylinder" on the net and you can see how it's done. Lots of good info.

No gasket between master cylinder and booster. MC should be sealed and booster should be also. Probably better that there isn't one so a person can detect if there's a leak in the MC...

Thanks ill look up and see what im getting myself into!