Have installed a 14 bolt rear in my 50 3/4t flatbed. Now it's time to figure out the p brake. The rear has the cables from the dOnor truck still attached but they are much longer and are set up to pull from one side. Before I get started do any of you know a straight forward solution?

Also on a separate note the cpp brake booster kit I got ain't holding pressure. bled everything, no leaks, get pressure on the pedal and truck brakes. after it sits have to pump it up again to build up pressure. Would appreciate a tip took it to the shop for the first time to get it bled and now its in a bay leaking cash.
Thanks
Aubrey