I just finished replaceing the drivers side caliper on my truck and now I have a strange brake issue. When I hit the brakes hard the pass side locks up fairly quickly, that side caliper was replaced a week prior to the other. Is this the nature of the beast because of the LSPV? The reason I think that is because thats where the line from the rear goes to.

 

Make sure that there is no air bubbles in the lines. Sounds like there is some air in the drivers side line. Kev

 

the line to the LPSV from the front brakes only goes to a servo that helps modulate the rear brakes depending on the LPSV position.
if the left is locking before the right, I'd re-bleed everything and verify the right caliper is actuating properly- the right may be sticking and diverting pressure to the left caliper thus locking it.

 

also, there may be a difference in the wear in on the pads between the two sides, if you didn't replace both sides' pads at the same time, the left pads with the left caliper and the right pads with the right caliper for instance. in which case the left pads are 'broken in' and the right aren't yet.