ok, my 87 4x4 pickup has started freaking me out, LITERALLY!
driving along, come to a stop light. apply light pressure and the pedal feels good and slowly brings her to a stop.
if I have to do an "emergency" or "panic" stop it starts out OK but you press harder it acts like it releases and pedal travel drops about 2" and gets hard again but doesnt act like its full braking power.

Here's what Ive done:
Replaced master cylinder
bled/flushed fluid

Any thoughts??????

 

How/what did you bleed?

Did this before you replaced parts?

:wabbit2:

 

Yeah, it did this (as I recall) several years back and I replaced the master cylinder and it went away. Put in a brand new (not rebuilt) unit to mo avail. Bled lines from front to rear as always.

 

Checkvalves?

 

you want to start at the rear at the farthest point then work toward the front. and check your proportioning valve out back

 

What checkvalve?

could this be something to do with the load compensation valve at the rear axle?
This has me puzzled. I guess i'll go read up on this valve in the FSM