front pass. brake hanging up...

[rickywideglide]

i have a 1986 gmc crewcab dually, front pass. side caliper is hanging up,PO said he already replaced caliper,my first thought was to order new front brake lines, wow they did not make this very accessible,probably will have to destroy hard line to get it out, this line looks to run to proportioning block,any chance that could be the problem(proportioning valve),i saw a test to check valve using test light,driver side is not sticking.. any thoughts or ideas greatly appreciated