92 front bleeding issues

[manyholes]

bought a '92 w250 auto, done the neglected list of repairs that were need and while i was doing the front brakes i figured what the heck and change out the front calipers. ive been fighting with the brakes for a bit, not winning albiet. broke down got a pressure bleeder for more than beer fund was happy about. im getting fluid finally thru the front bleeders but when i first crack the bleeder, it shoots out then trickles right away, when cracking on the rear, it pushes a fountain of brake fluid for as long as you want to waste it.

so im thinking bad proportioning valve?
new flex lines for the front(all 3)
no signs of leakage anywhere i can see and ive been under it steady

before i bought the pressure kit i couldnt build any pressure in the brake system to bleed with, tried a vaccum bleeder with no luck so went to the pressure bleeder.

On our (i think) abs spliter after the master(aluminum body), i couldnt get fluid to come out the bottom off it for the front and realised that there was a pressure pin or something on the backside, after i depressed it , fluid came thru but still no pressure to stop. if anyone can chime in on this piece and the plunger in the back it would be appreciated

brake system was working good prior to repair, had to change out a rotor, pads and figured due to unknown history id do the calipers,

when i did my 90 they bled like a hot damn so i dont know . this truck is down with pilled brakes and my 90 is down with a scrambled charging system dont think the wifes journey will pull my boat to get to the lake so i wont give a damn bout them trucks for a night either lol

repair list on truck already done
front half shaft u joints
front bearing repack/seals
rebuilt front drive shaft
syn oil in both diffs and 'case
trans filter and some lucas tranny stuff for extra protection
rebuilt the rear diff complete (d70 31 spline)
front brakes

[ellis93]

The way the proportioning valve works is the harder you press the brake pedal the less fluid pressure is sent to the rear. If one is working properly that little pin sticks out and the harder the brakes are pressed the farther it protrudes. If the brakes are released,the pin should be flush with the valves housing.
If it were me, I'd start cracking the lines one at a time for the front, starting with the master. I've seen,on other vehicles, where there would be trash inside the piston bore of the master and cause something similar to what you describe. I've not seen a lot of problems out of the proportion valves,but it is man made.

[Hansen01]

on your 90 did you get a new voltage regulator on the firewall?? that could be why it wont charge

[manyholes]

the 90 has a new battery, tried 2 new voltage regulators(one ac delco, one from lordco), delco alternator and grounds cleaned up. took apart and cleaned the connections on the main power feed as well. tugged at the fuseable links. nothing loose

what is the block on the frame rail for?

[ellis93]

This one


If so,its nothing but a tee/distribution block. No voodoo there

[manyholes]

my block is a lil different but thanks for clarifing for me.

[manyholes]

sorry for long delay, back at work and computer was fried, master cylinder was the culprit. started from the top and work my way down. i had decent spray coming out of my old m/c line ports but when i pulled it, the piston wasnt traveling all the way back preventing proper pressures. so brakes are done now and on the bright side i got a nice and fancy pressure bleeder for my brake jobs now, its a KD tools pressure tank, looks like a pony keg almost. works real good