Vehicle is a '94 Mitsubishi Montero SR with ABS
I went to replace worn brake pads on the rear and found that rotted slider-pin "Boots" had allowed water-contamination, causing both (upper) "Pivot Pins" to seize bad enough that a box-wrench would strip the hex-nut, so I had to pull both calipers brake-hoses off the rear calipers in order to access them for removal with a 1/2 Air Wrench and 6 pt. socket...I plugged the lines to prevent a complete bleed-out of the system -- and never emtied the Master for doing-so -- but upon reassembly and having now pumped over 2 quarts of brake-fluid via "Gravity-Bleed", w/helper doing the "Pump 3x's 'n HOLD/Crack the bleed-screw", "Line-in-the-Fluid Bottle 'n PUMP", AND "Vacuume Bleeding" (with a Vacula) -- I can NOT get the air out of the system!
"Bleeding-proceedure" is: "Vacuume/Drain & refill Master Cylinder Reservoir w/fresh fluid and bleed system as follows: R-R, L-R, Leveling Porportion Valve (LPV), R-F, L-F (repeat if needed).
I'll get both rear bubble-clear with SOME improvement, then bleed the leveling Porportion-Valve (LPV) (with no-change), then LOOSE PEDAL (to-the-floor) upon bleeding the R-F and/or L-F.
Despite both front calipers bleeding bubble-clear I'll now have NO PEDAL WHATSOEVER...so I'll start-over -- as proceedure instructs -- and get only the same result!
Granted, the System is now bleeding very clean, but I've done the "repeat proceedure" thing more times than it ever should've needed...(and it's become time to "walk-away" ; )
Next I'll try bleeding it with the vehicles weight ON THE FLOOR vs. "Lift" ~ JIC hyper-extension of the suspension is allowing the L.P.V. to by-pass air in/around the system : ?
I'll post my progess as soon as I make some, meanwhile if anyone that's "been-there done-that" has a solution please DO share it here, thanks!