Hi all,

I have a really soft brake pedal and so far I've flushed out the fluid, replaced the brake master cylinder (bench bled with a kit and rebled the brakes), adjusted the rear brake shoes and at the moment I can alteast pump the pedal a few times to build up some pressure but the truck does not give me much confidence with its stopping power.

I noticed in the Haynes manual it calls for pulling the pin out on the brake pressure differential valve before bleeding the front calipers but I can't either pull it out or push it in any with moderate force (it will jiggle a little bit so it doesn't seem "stuck"). I wonder if there's something going on with this part that is causing much of the soft pedal?

It feels like a bad brake master cylinder where you push right through the front circuit before hitting the rears. According to the picture of a similar one I found online it looks like you can take this puppy apart. I was thinking of trying that to see if some gunk was stuck in there causing my problem but wanted to check with y'all first. Thoughts?...

(I don't loose brake fluid, it doesn't leak all over anything that I can see, I was able to use a handheld vacuum pump to suck fresh fluid through each bleeder screw, etc.)

The pin is "C":