Air Plumbing Redo Troubles

Blue knob is for emergency spring brake release. They always had their own isolated tank. If you were to lose all psi and brakes clamp down the blue knob is supposed to give you two shots to release brakes to move to a safe spot. They were called Bus brake valves or California valves. They were part of the original 121 brake reg of the mid 70’s for trucks and adapted from busses. The original idea on busses was if it got caught on r r tracks or in intersections with complete air loss the blue valve will allow it to move.

 

Forgot to mention the blue knob does not stay in. It is designed to spring back against your pushing it so it only lets air pass thru it at your control.

 

Not nessary to keep working. They redacted them for trucks and stopped using them in the 1980-83 time frame. The old style pp1 valve and Qr1 valve will work fine. If you have air ride you could use the old tank as a supply/ reserve for it. Keeps more air for suspension and helps the compressor run a little less.

 

Yellow and red should not spring back. Only blue does. Most systems the blue knob would not let air flow thru it unless yellow was popped out. Kinda a cheater brake release in that respect, but you had to hold knob in. Keep in mind too the blue does not release trailer if it fails only tractor. Trailer always had to be drug by tractor power.

 

California valve is what it's always been called in my circle.
My california valve does stay in or the truck won't move. But it has it's own separate air tank, smaller in size.
My old Topkick's valve setup.

 

this is a early version of the valve setup that was made by Westinghouse to retrofit spring brakes on a pre spring brake truck. The toggle is what would become the “yellow” knob the button is the “blue” knob. Tractor protection valve “red” is a separate toggle mounted under dash.

 

The confusing part has always been the “not for parking” on the red knob. That is pre 1975 before spring brakes were mandated on trailers. After that the red knob controls spring brakes on trailers but they never took that wording off. Don't know why. The red knob started out being called “Tractor Protection Control” pre 121. Normal position supplied air to trailer and released springs. Emergency position also “bobtail” position released air and applied springs.