So...where is the fluid going when you press the pedal. Since the truck is fairly new to you, I'd check for a missing brake pad (or shoe), or maybe even a rotor. I vaguely remember a possible issue with position of the MC piston...If it's not correct, fluid will just recirculate to the MC...
I concur with the other guys. Rebuilt the engine at 160k (manifold gasket leak...melted piston) I bought a pump rebuild kit at the time, but the pump measured as new so I left it alone. At 300K+ oil pressure is great and the kit is still in the spares box.
For anyone who'd like to dig deeper....Check out Jim Comstock's oil test project. Jim is a Norton Motorcycle guru and put a lot of time and effort into this. Yes, ...this is designed to find the best oils for Norton Commando engines, but the flat tappet requirement is the same...
Which compressor do I have? TIA I'm asking because this one sounds like it's grinding marbles and the ID tags are unreadable. Doesn't necessarily look like either of those available from Rock Auto.
Don't recharge without adequately evacuating the system. Moisture will react with refrigerants and cause corrosion over time. Moisture will accumulate at the expansion valve, freeze, and can close it off. The increased pressure can damage the compressor.
I've been running a powerSurge with no problems so far. I went with the PowerSurge because I DID see a few references to fueling problems (FJ60 + Sniper) when using an inline pump alone, and didn't want to mess with the tank. I'd like to hear from anyone using an inline pump alone on a '60...
Seems to be a little confusion here and there. Remember...Duracool and Envirosafe are hydrocarbon blends and not freons (fluorinated hydrocarbons). Please forgive my redundancy.