Hydroboost brakes- no pressure to rear?
I converted my FF 14 bolts brakes to disc, using 78 K25 calipers and rotors on my 97 K2500. When I did this (4 months ago), I threaded the stock rear brake line into a small adapter (to change thread) and then into the caliper.
I bled the brakes like any other vehicle... pump, pump, pump. hold, bleed.
I then did the front when I put the Dana 60 under it. Changed the brake lines (to longer ones), filled the m/c and pump pump pump , bleed.
Brakes worked great! They were a little strong in the rear with the disc, but they worked great for 4 months. I then developed a squeal in the rear, which was caused by gear lube leaking from the hub seal, onto the rotor.
I dissasembled the axle, brakes and hub to repair.
Upon re-assembly I cracked the stock hardline when the caliper slipped out of my hand, so I ran to the parts store, bought some line and replaced the lines from the rear axle "T" to the calipers.
The M/C never ran completely dry.
I filled the m/c, and proceeded to pump and bleed as usual...... nothing.
I now have very little pressure at all. I disconnected the lines at the "T" and checked again.... with someone hitting the brake I still have very little pressure thru the line. I reassembles the lines and gravity bleed everything, then used a mity-vac, then tried bleeding as usual, and I still have no pressure- the pistons arent even moving in the calipers.
The pedal blows right thru the first half of its stroke, and is SSLLOOOOWWWW to return.
Any ideas? What did I do wrong? How do the proportioning valves work- could it be "stuck" and not allowing pressure to the rear?
When my assistant has the brakes pumped up, and I crack the bleeders, fluid just peeters out, instead of spraying whether the engine is running or not.
Ideas? Bueller? Bueller?