1974 1210 Camper special no brakes leaking booster.. Which booster?

[741210AK]

Hi there
I just got "paid" for a carpentry job with a 1974 1210 "camper special" International pickup with 345 v8, 3 speed automatic. Plenty of work has been done on this truck over the years and it starts and runs on its own after a few days of tlc. However...

Four years ago the previous owner was heading downhill with a full load of firewood and the brakes disapeared. He drove it back to the top of the hill and parked it. My diagnosis started with the master cylinder. With the engine running an audible vaccum leak was heard eminating from the joint between the booster and master cylinder. So is this the reason for no brakes? Is the booster likely bad too? I thought maybe.

I have been trying to find a new booster, but the parts are confusing. My booster looks like the part found on Scout II with front disc, but my 1210 is drums all the way around. Could the factory have installed this as a more powerful booster for the "camper special"? Could I use a simpler (thinner) booster and just re-bend the lines from the junction block? See image. Anyone know about this? My booster looks like IH part # 473416c91. Need to get this rig moving and off the guys property, thanks!

 

[blue smoke]

The change in 74/75 was to use the same booster as the Scout. There is no difference in the two except for size and appearance. If you hear a vacuum leak you definitely have a bad booster.

the brakes disapeared

Did the pedal go to the floor or what actually happened? If the booster went out the brakes would be very hard to apply but would still be there, so it May not be the master.

 

[741210AK]

Man, thanks for getting back to me blue smoke.

All the seals between the master and the booster were rotten/gone. When the brakes went out the pedal went to the floor. I am guessing maybe the master was leaking into the booster and then started sucking air when the resivour emptied.

Maybe there is a leak somewhere in the system, but without pressure it is hard to diagnose. Adding fluid to the system and pumping produced no discernable pressure or leaks. When the engine is running the junction between the booster and master has an audible vacuum leak that can be heard above the sound of the engine. There is a good clacking in one spot, like maybe a stuck valve, loss of vaccuum? But otherwise engine runs smoothly. The booster seems to still add a bit of help, maybe the new master will clear things up.

IH parts guy suggested maybe someone put a Scout II booster on for a conversion to front disc brakes. I am going to get a master clyinder right now, hope it is the right one... We'll see. Then put it on this afternoon, ahhh it already int her teens up here, perfect for shade tree wrenching.

 

[FDChappie]

Before you do that. Rebuilt vacuum boosters usually come with a m/c. So to fix that vacuum leak you are hearing you May be buying 2 m/c's.