RWAL is the correct term. look it up and you will find:
What's needed.
1/2" wrench/socket
9/16" and 1/2" flare wrench for brake lines.
5/16" male x 1/4" female brake line adapter fitting. ie, EDELMANN #258450 (available at O'reilly auto parts.....about $5.)
15 minutes + time to bleed rear brakes.
Master cylinder has fluid reservoir on top. Isolation dump valve is below(to be removed). To right of that is proportioning valve (keep that). Attached to proportioning valve is control box (black plastic with wired connectors).
You must be registered for see images attach
Start by removing control box. Remove connectors from rear. Top one is part of vehicle harness. Lower plug connects to other part to be removed. Jiggle box, pull towards front of vehicle, should slip off.
You must be registered for see images
Should look like this....
You must be registered for see images
Next, disconnect two lines from bottom of isolation/dump valve...one is very short and connects to proportioning valve. Disconnect from proportioning valve as well. Remove two bolts (1/2") from top of valve where it attaches to bracket.
You must be registered for see images
With that out, its easy to see what's left to do.
You must be registered for see images
You must be registered for see images
Fitting from Oreilly, $5.49 allows use of existing brake line and screws into proportioning valve. EDELMANN 258450. Male threads are 5/16", female are 1/4". This is a brake fitting. Can find something similar using these dimensions.
You must be registered for see images
Screw that in bottom of proportioning valve. Use teflon tape and a little bending to reposition and tighten it up.
You must be registered for see images
Bleed Rear brakes and better pedal feel.
Isolation/dump valve is thought to degrade brake pedal feel and and trap air. System only provides anti-lock for rear wheels, via drum brakes.
88-94 gets rid of brake light.
1993 GMC - no adapter needed.
A rubber button on one end of porp valve- press this to recenter valve.
One of connectors (4 pin) is removed when deleting isolation/dump valve. Other connector, cut wires at staggered lengths, tuck into wire loom. Orange wire will be hot so if it shorts out, will need to replace 15 amp brake lamp fuse.