With no BH installed, your hyd path should be like this.
Pump to hyd blk, then to FEL, FEL OUT back to hyd blk PB to 3pt, then to tank.
All return hoses should go to tank unimpeded.
If BH installed, then the PB out of the hyd blk would go to the IN port of the BH, and the BH OUT hose would go to a return hose.
You probably would not use the 3pt with BH connected.
The bolt on the bottom of the hyd blk, is the tractor relief.
You might check the relief pressure.