A spring brake relay valve works on the same principle as the service brake relay valve, although it has the opposite effect. This type of relay valve responds to a major drop in pressure at its control-port by opening its exhaust port, which causes the air from each spring brake chamber under its control to remotely exhaust, thus the spring brakes much-more-quickly than would otherwise be possible if the air were required to discharge via the yellow parking-control valve on the . In a dual-circuit air brake system, air from both the primary and secondary reservoirs is fed into the supply-port of the parking-control valve, as well as the supply-port of this relay valve; it is merged via two-way check valve. The delivery-port output of the parking-control valve connects to the control-port of this relay valve; this enables the spring brakes to be controlled via this valve. The merged air from the parking-control valve prevents air-loss from only one braking circuit from causing the spring brakes to automatically apply. This gives the driver more control, and prevents the vehicle from grinding to a halt in an unsafe location. However, with this increased control, comes increased responsibility on the part of the driver: If air is lost from the primary circuit alone, the spring brakes be manually applied by the driver via the parking-control valve; otherwise, the front service brakes may not be enough to stop the vehicle safely in an emergency—especially if the vehicle is heavily loaded, and/or traveling at a high-speed. In fact, the driver's failure to manually apply the spring brakes in this situation could lead to catastrophic failure of the front brakes due to overheating, since it could cause the front service brakes to exceed their design-limit for energy absorption. QR1C air valve speeds up the process, with anti compounding, meaning trailer and service brakes will function 1 second between each other. The relay valve's function is analogous to the used in electronic circuits.
An explanation of how a one way check valve works in the truck air brake system. Created by the School of Motive Power Technology at Fanshawe College, and the LO Studio.
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Additionally, if you simply replace the AIR pump the problem may return again(and again). If you replace the pump, also clean out the hoses and replace theone-way check valve. If this is on a GM model that the TSB applies to, followthose instructions in the link above. In a few cases, people have put a smallhole in the rubber cover on the pump which allows any water to drain out.
This is accomplished by using a one-way air pump check valve
About 90% of the time that this code is set, the one-way check valves haveworn out or failed and allow water (which occurs naturally in the exhaust) backinto the pump. In any cold climate, especially in climates with higher humidity,this water may be more excessive. The water partially fills the AIR pump, itcan then freeze. When the PCM commands the pump on, if the pump is frozen itcannot turn, thus overloading the circuit and "popping" the fuse.
Discount One Way Air Valve | 2017 One Way Air Check ..
A check valve is a fitting that allows compressed air to flow through it, but only one way. If the air tries to flow back up through the check valve, the valve flapper or similar device shuts, and air cannot escape.This video describes the various types and sizes of Check Valves for an air compressor. The Check Valve is located in the tank inlet and is a one-way valve that holds the air in the tank after the unit shuts off.