I posted a similar question (about my '85) a while back on this forum and got some good ideas, but I still haven't figured anything out. My current 14 bolt semi-floater tends to lock up easily in damp and/or cold conditions. My original 10 bolt did the same thing.......just not as severe. No fluid leaks, no grease contamination, yadda, yadda, yadda. I just ride the brake a little when I first get underway, just to drive off any moisture. Good luck!
2016 Chevy Colorado Z71, 2.8 Dmax
Former Diesels:
2014 Chevy Cruze 2.0TD
2009 VW Jetta TDI
Former Trucks:
1972 GMC C-1500 LWB, 350 gasser, TH-350, 3.73's SOLD long ago
1985 GMC K-1500 SWB, 305 gasser, SM465, 4" lift, eight lugs fr & rr. SOLD long ago