Hello All... I am experiencing extremely uneven front brake wear (left side) on my 1992 Beretta GT. It is equipped with the 3.1L and ABS. I have experienced this type of problem on other vehicles, and the culprit has always been a defective / worn out caliper. Replace the caliper - problem solved. However, after replacing the caliper and rotor on the left, as well as new pads on both sides, the left is still hanging up. That leads me to believe that the problem is probably the proportioning valve(s)?
Now, here is the confusing part (at least for me)

. There appear to be two proportioning valves on this car. A primary in the master cylinder, and then, a secondary that seems to be linked to the ABS. Two lines come out of the master cylinder into this secondary valve, and then from there, the four brake lines to the wheels. This secondary valve has two bleeder valves and two electrical connectors on top that trip the ABS warning light on the dash when unplugged. Unfortunately, my local Chevy dealer parts dept. only shows a cut with the primary valve, and doesn't seem to know what I am talking about when I describe the secondary. Given all of that, I have a couple of questions:
1) Does the primary proportioning valve in the master cylinder split between front/rear, left/right, or diagonally? If it is left/right, I can try a rebuild kit on that first (after I pull the left rear, of course, to see if I have increased wear there also.)
2) If the problem is
not the primary, does anyone out there know where I can find a rebuild kit or a complete replacement for the secondary valve?
Thanks in advance for any help out there!!