Replacing brake booster on a 72...need advice.

[Fargenamps]

Hi Guys,

I researched previous threads and found a suitable mini truck/4 runner booster to replace my non working (and very hissy) original 72 brake booster. I plan on mating up the stock master cylinder with the replacement booster as I still have the original drum brake setup

1.Do I need a proper gasket between the booster-master cylynder or can I use RTV?
2. Do I need to bleed the brakes off after I get done?
3.Any grease etc needed on the rod where the booster/cylinder mate up etc?

Any and all help appreciated as this is my first take at this particular repair.

Thanks in advance.
Benjamin

 

[fieldsken1]

1 yes if it had one in there i would replace it correctly dont skimp on brakes they are important
2 yes if you open any fittings but you should anyway wont hurt
3 no nothing needed

 

[Fargenamps]

1 yes if it had one in there i would replace it correctly dont skimp on brakes they are important
2 yes if you open any fittings but you should anyway wont hurt
3 no nothing needed

Thanks man!

 

[handcannon]

Something else to watch for if you get the booster from a pick-n-pull. Sometimes there will be a spacer between the booster and firewall. Grab that because you may need it to set the right rod distance between the booster and the brake pedal on your 40. Another thing to get will be the vacuum check valve. The valve on your 40 booster is built into the inlet of the booster. The mini-truck valve will be in the vacuum line going to the intake manifold. This valve holds vacuum in the booster after the motor is shut down, giving you a couple or so brake applications before you lose power assist.

I learned these things in the school of hard knocks.
Don

 

[Fargenamps]

Something else to watch for if you get the booster from a pick-n-pull. Sometimes there will be a spacer between the booster and firewall. Grab that because you may need it to set the right rod distance between the booster and the brake pedal on your 40. Another thing to get will be the vacuum check valve. The valve on your 40 booster is built into the inlet of the booster. The mini-truck valve will be in the vacuum line going to the intake manifold. This valve holds vacuum in the booster after the motor is shut down, giving you a couple or so brake applications before you lose power assist.

I learned these things in the school of hard knocks.
Don

Hi Don,

Great advice...thank you.

Yes I have the spacer which is good news...I may still have to trim down the threaded mount to the pedal but we'll see.

I was thinking about that check valve and remembering my early 90's Toyota had the check valve in between two hoses just as you mention instead of on the booster...wish me luck...I'm going in

Cheers!
Benjamin

 

[DonPancho]

Is this your daily driver? If so understand the need to get immediate replacement, If not then Just repair what you have, heck you could still have your original rebuilt, while you use the donor, had mine rebuilt and it turned out very nice, see link in sig, I discuss in my project thread.

 

[Fargenamps]

Can you say long overdue???I don't know how the PO lived with this...booster was completely gone! I was working with model T brakes here!!!
Luckily I had Success! Installed the donor and it works very well! Feels good to have some solid brakes again. Once I bleed the brakes and do a adjustments all the way around this baby will stop on a dime...on my way to get a check valve now!

Thanks!!
Benjamin