Mini truck master cylinder, which port is which?

[ibinazbass]

Hello all, in the middle of a front disc conversion on a 1967 40. New mini truck master & booster, all new brake lines, etc. My question is, the pedal doesn't get hard. Rear brakes are adjusted, bench bled the mc twice, bled the whole system 3 times, checked booster to mc pushrod length, checked pedal to booster pushrod. No air has come out while bleeding recently, all clean new fluid all the way to the rears. Pedal still only gets hard at about the last 1" with engine off. Pedal stays hard while held down, so no leaks. Which port on the master is for disc and which is for drum? Maybe I got the wrong axle in the wrong port? I'm assuming front port is disc and rear is for drum? This is the only thing I can think of other than a bad mc? Any other ideas?

 

[ibinazbass]

Really?! No one?

 

[SnowroxKT]

Dumb question, but are pads installed?

 

[Shark56]

Not the best picture.
Can't recall what year master but from an early Tacoma.
Rear goes to proportioning valve see attached to booster. Do you have Proprtioning Valve.
This is on a 74 with disk in front, drum rear.

 

[JackA]

Do the brakes work? You can't judge brakes on the pedal feel alone.

 

[ibinazbass]

Dumb question, but are pads installed?

Pads are indeed installed.

Not the best picture.
Can't recall what year master but from an early Tacoma.
Rear goes to proportioning valve see attached to booster. Do you have Proprtioning Valve.
This is on a 74 with disk in front, drum rear.

View attachment 1548065

No proportioning valve yet, was going to wait and see if there was too much assist for the rear or not.

Do the brakes work? You can't judge brakes on the pedal feel alone.

The brakes do not work. Moves the pads and will hold the vehicle slightly but would certainly not stop the vehicle safely out on the road. With the engine running, pedal goes right to the floor with next to no resistance.

 

[John Armas]

Hello all, in the middle of a front disc conversion on a 1967 40. New mini truck master & booster, all new brake lines, etc. My question is, the pedal doesn't get hard. Rear brakes are adjusted, bench bled the mc twice, bled the whole system 3 times, checked booster to mc pushrod length, checked pedal to booster pushrod. No air has come out while bleeding recently, all clean new fluid all the way to the rears. Pedal still only gets hard at about the last 1" with engine off. Pedal stays hard while held down, so no leaks. Which port on the master is for disc and which is for drum? Maybe I got the wrong axle in the wrong port? I'm assuming front port is disc and rear is for drum? This is the only thing I can think of other than a bad mc? Any other ideas?

Do a stop test at a very low speed. You might find that they are ok. Sitting without the motor running the pedal will be low. I ended up putting inline residual valves in my 70. They brought the pedal up dramatically.

 

[JackA]

It has the 67 rear drums still right? When the drum is on with wheel tight do the rears have some drag? If not, might need more adjusting.

Did you replace all the lines? Could need more bleeding too.

I had both these issues on my current 40 build.

 

[ibinazbass]

Do a stop test at a very low speed. You might find that they are ok. Sitting without the motor running the pedal will be low. I ended up putting inline residual valves in my 70. They brought the pedal up dramatically.

I will try this stop test.

It has the 67 rear drums still right? When the drum is on with wheel tight do the rears have some drag? If not, might need more adjusting.

Did you replace all the lines? Could need more bleeding too.

I had both these issues on my current 40 build.

Correct, 1967 drums. They are adjusted properly (possibly 1 click too tight even.) Replaced all front lines and bent the rear line from the junction on the passenger frame rail, near the engine, up and over the engine compartment to the M/C. Could need more bleeding but I've used an entire quart already, bleed til you die I guess!