Leaky steering box cause hydroboost brakes to drag?

[Warkmeister]

Title mostly describes it, but I’m having trouble wrapping my head around the possible physics/mechanics of this issue. 1981 chevy k30 crew cab srw. Off-road designs rear disc conversion. Ive resealed the hydroboost unit with a seal kit, bled the brakes (mostly I hope....slight chance of bubble in line?) new proportioning valve with the rear line plunger/core removed, new working master cyl. Newer calipers (2yo) and soft lines all the way around. Brakes work great when the truck starts and drives right off the bat, but slowly start to grab as time goes on. Like in 10 min of country road driving with some stops. I know the steering box is leaking and I am beginning to notice there might be a correlation between needing to add fluid to the PS reservoir and the grabbing being worse. Any technical ideas? Could the leaky box be letting air in the booster system instead of just letting fluid out? Could that then stimulate the hydroboost to apply pressure to the MC?

 

[SirRobyn0]

I don't know if you are looking for help on this still, but I've never seen a P/S leak even in a hydro boost system cause the brakes to grab. I'd looking at the master cylinder and calipers first. You have no idea how often we see those kind of defects even in new parts at the shop.