Rear Brake leveling/propertioning thingy

[Mild Thunder]

Hey guys. Just picked up a 1989 R3500 crew cab dually. Put on new rear shoes, adjusted them, and still the brakes dont feel that great. Read somewhere that the rear height sensing valve could be not allowing full rear braking action. Is there a way i can disconnect the rod that goes to it and wire it to the full open position? This truck will be used to pull a boat in the summer, and not in the winter at all.

Also, when i come to a stoplight, the pedal sinks a tiny bit after having my foot on it for about 5-10 seconds. Not to the floor, but just a bit. No leaks anywhere, and not losing fluid. Not sure if this is a charactoristic of the hydroboost?

[mountaindrew]

Hydroboost should have that thing stopping on a dime.  Somebody with experience will chime in any time. 

[79k30guy]

regarding your brake issue at stoplights...

I had literally the same issue on my 1 ton.   It was the master cylinder.  with a core charge refund, it was a $20 fix.. 

[Mild Thunder]

regarding your brake issue at stoplights...

I had literally the same issue on my 1 ton.   It was the master cylinder.  with a core charge refund, it was a $20 fix.. 

Did the new master give the brakes a better feel/power? Or just fix the sinking pedal?

[79k30guy]

regarding your brake issue at stoplights...

I had literally the same issue on my 1 ton.   It was the master cylinder.  with a core charge refund, it was a $20 fix.. 

Did the new master give the brakes a better feel/power? Or just fix the sinking pedal?

I'm not sure the brakes stop the truck better, if they do its hardly a noticable difference..   it definantly fixed the slowly-sinking pedal.