Where should I plumb my progressive braking system in an MC8

[lv2rescue]

HI Folks,
I have an MC-8 bus conversion. I am installing a progressive braking system for my towed and this includes plumbing into the coach's air brake system. Does anyone have some guidance as to where I should plumb into this system? Thanks in advance.

[luvrbus]

There are extra plugs on the drive axle brake relay to do just that

[lv2rescue]

Thanks luvrbus!