Spring Brake
Valves

Modern Spring Brake Valve Exhaust Curve
To prevent spring brake drag the 110800, 110700, and 110500 are designed to retain pressure in the trailer’s spring brake chambers even with diminishing supply line pressure. The chart below shows typical response to a varierty of supply pressures
Supply Line
The supply line is the air line from the trailers towing unit (tractor) that is responsible for replenishing the air brake reservoirs. It also signals the trailer to go into emergency or park mode (spring brakes engaged) when the air pressure drops.

Spring Brake Chambers
This term is used to describe the portion of the brake actuators that are used to engage the brakes when the trailers is parked or goes into emergency lockup. Although integrally linked to the service brake actuators they are operated separately via the spring brake valve.
 
Spring Brake Valve

Typical chamber levels with diminishing supply line pressure

Supply Line Spring Chamber
100 95
95 95
90 95
85 95
80 95
Supply Line Spring Chamber
75 95
70 95
65 95
60 95
55 95
Supply Line Spring Chamber
50 95
45 95
40 90
35 80
30 70
Supply Line Spring Chamber
25 60
20 45
15 35
10 25
5 10


Chart


Spring Brake Technical