pb4ugo
SILVER Star
The reservoir towards the frt of the vehicle is for the frt brakes, but you never know what a po might have done.
Your booster is nothing more than a really big vacuum canister, it's there to assist in pedal pressure. If it holds manifold vacuum it should be good. The PO of my May of 1975 40 had a stk disc brake frt axle installed and used the stk 1975 drum brake m/c. I drove it for a couple of summers b4 putting it in storage and the brakes worked perfectly. B4 the internet, I installed an FJ40 disc brake frt axle in my 72 40, I had the same result with the drum m/c and 1/2 my brake and bleeding issues went away. In my expeirence, the drum master has a 1" bore and residual valves, the 1976 and later m/c for frt discs have a 7/8" bore and 1 residual valve for the rear drums. I removed the residual valve and installed a proportioning valve when I went to rear disc's & all my brake and bleeding issues went away.
If the pedal pumps up higher means you still have air in the system. From your description it sounds like the issue is in the rear. You can isolate the issue rear or frt by carefully using a pair of vise grips and stopping fluid flow to the rear and then to the frt. This is an unorthodox test and can hurt your soft line if you're not careful. Your going to clamp the rear soft line to stop the fluid flow to the rear and then see if the pedal is better/higher. If the pedal is better then you have air in the rear circuit, if there's no change then the problem is probably in frt or the master. Be sure to carefully adjust the vise grips. You want to stop the flow, not crush the hose. You can do the same to test to the frt. I haven't run rear drums in decades but have read a many threads where folks have poured multiple qts of fluid trying to bleed the FJ40s old antiquated drum brakes. Most folks are successful by adjusting the brake shoes tight to the point the tire wont spin and the shoes are tight against the drums, so the wheel cylinder pistons cant move, then they bleed the wheel cylinders. Leave the tires on. This helps force the air out of the cylinders. Once the air is out of the circuit, they re-adjust the brakes per the FSM.
Your booster is nothing more than a really big vacuum canister, it's there to assist in pedal pressure. If it holds manifold vacuum it should be good. The PO of my May of 1975 40 had a stk disc brake frt axle installed and used the stk 1975 drum brake m/c. I drove it for a couple of summers b4 putting it in storage and the brakes worked perfectly. B4 the internet, I installed an FJ40 disc brake frt axle in my 72 40, I had the same result with the drum m/c and 1/2 my brake and bleeding issues went away. In my expeirence, the drum master has a 1" bore and residual valves, the 1976 and later m/c for frt discs have a 7/8" bore and 1 residual valve for the rear drums. I removed the residual valve and installed a proportioning valve when I went to rear disc's & all my brake and bleeding issues went away.
