Brakes won’t bleed, help!!!

[Grit dog]

Perhaps we need to back up to what the symptoms were before you started. (We know the fronts were hanging and got really hot or something. Not sure I’ve ever seen “new” brake pads look anything like those. )
But what else was going on? Did it have rear brakes before you removed the hard lines from the MC?
Why did you remove those lines from MC to prop valve? Leaking?
List of what’s “new”, what’s old and unverified and whether the brakes actually ever worked right and when they didn’t and what the symptoms or repair was. All that helps. We’re shooting beyond daylight hours but not totally in the dark here. But leaning towards a 40+ year old dilapidated brake system in general and a spotty approach to repairs.
Another consideration with old cars or old anything really, Especially with brakes. Aside from non rusty hard lines, an old car that has sat unused and in disrepair may need “everything” to keep a person from chasing their tail.
But start first with history and what’s old what’s new and what the symptoms were along the way. Including the history before you bought it (did it sit unused for ….years).

 

[Grit dog]

And a good practice for older or seldom driven vehicles or machines and even newer daily drivers…. If you have a good brake system to start with, IMO one of the biggest things that will degrade it is old brake fluid that has absorbed moisture. Without moisture things don’t corrode or corrode as fast.
Brake fluid is cheap. I have a fair number of “old” machines around. And by old more than 5-10 years old is old for brake fluid in anything. Problems get worse when 5-10 turns into 20 and now corroded up internally.
I’m also lazy so the thought of proper brake flushes is time consuming. Necessary if reviving something already old and corroded up. But if starting in good condition, just add a fresh reservoir of fluid every so often.
I don’t have a set schedule but I generally drain the master cyl on clutches and brakes and refill with fresh fluid probably annually or whenever I see the fluid looking dark colored.
Can’t say for sure, but I have 20-50 year old stuff that I’ve owned for 20 years that I’ve not had brake issues with.
And if it’s something still operational but you know it’s old junky fluid I’ll suck the mc dry and fill, drive it for a while and repeat multiple times.
Just general thoughts on brake system maintenance.

 

[Ricko1966]

Yeah I replaced the two lines that come out of the MC and the front right hose. I was trying to do all of them at the same time but couldn’t get the 2 front lines off the proportioning valve. I think I have the front bled but the brakes feel very spongy. Good enough to get the truck out of the garage but not long term. Do I still need to bend bleed the MC?

If you ran the reservoirs dry you may need to bench bleed the master. 2 The lines you put on were 100% full of air so you should have cracked the fittings at the combination valve and bled there as your second stage in bleeding so you didn't push all that air into the combination valve then into the lines etc. Fronts are work8ng,everything I just said and previously said may still apply to the rear circuit.