LSPV- Load Sensing Proportional Valve (Vehicle Braking System)


Can anyone tell me more about this?
it looks to me that i can adjust the load sensor by adding/removing air?
this is whats on the label on my drivers door.

Front circuit....... for 100 bar
Rear axial weight 450kg.....24 bar
rear axial weight 750kg.....56 bar
travel 450kg...750kg.... 24mm

if i can add air.. where on the van can i do it?