Calling all those who know more about RWAL systems than I
The patient, 88' C1500, 305 TBI, 147,xxx on the clock. The other day I
noticed brakes were about 50-60% of where they normally are. Felt like the
rears were out of whack. Pulled both drums. Both were out of adjustment
(gotta love GM "self-adjusters"). Snugged up RR, adjuster on LR was frozen
so I took it off, broke the nut loose, cleaned threads, lightly greased and
put er' back together. As soon as I fired her up, brake light came on and
stayed on, and NO PEDAL. Goes right to the floor, I have about 5% of
regular braking power.
Here's what's been done in order:
1) Inspected for leaks bumper to bumper (all dry).
2) Checked for adequate vacuum at the power booster (20 in/hg, right on the
3) Unplugged RWAL module. No effect.
4) Replaced master cylinder, front calipers and flex hoses (damn bleeders
broke off when I tried to loosen them after replacing MC, farkin' flex hoses
were cracked so I replaced them as well). Talk about a 30 minute job
turning into a 2 hour ordeal............anywho, still no pedal at this
5) Replaced power booster and bled the SHIT out of the system. Used a
vacuum pump, and pumped 1 pint of fluid through each line. Still no pedal.
Where I am now:
Brakes pump up fine with motor off and bleed well. With brakes pumped up
and pedal held, when the motor is turned over the pedal goes straight to the
floor. Brake light stays lit. Brakes about 5% of normal.
I have an ABS hydraulic module (isolation/dump valve) sitting in my garage
which I'm considering throwing at it based on the following theory. If dump
is stuck open, it's not holding pressure to the rears. The proportioning
valve sees low/no pressure to rears and adjusts front pressure accordingly.
The result, no brakes.
Any thoughts before I go and get covered in brake fluid again?