Bill,
If only one side up front locked up, it doesn't matter what you do with proportioning valves and rear brakes, you still have a problem with one of your front calipers. Pull them apart and rebuild them! As Jack mentioned, there are inexpensive kits to do this.
Stock caliper rebuild article and videos linked here:
http://www.poca.com/index.php/...ront-caliper-rebuild
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