[Shotimes] rear brake questions

[van Oss]

I have been refurbing the rear brakes on my 91.  Replaced the parking-brake
cables, both rear calipers, pads, hoses, and had the rotors ground.

One problem:  The return spring on the Left Rear caliper seems not to be
strong enough.  When I release the parking brake, the lever on the caliper
does not return to position.  I can pry it up, releasing the rotor, but it
will not release by itself.  Did I get a bad caliper?  Has anyone
experienced this?  Anything I can do to correct it?

Also, I never noticed this before:  I seem to have parts missing from the
proportioning valve.  The valve body itself is not in any way connected to
the lateral arm.  Is that a bad thing?

Joseph van Oss