303.02.0094 4-circuit protection valve — KNORR-BREMSE

The heavy duty 4-circuit protection valve is a critical component in the pneumatic braking system of heavy commercial vehicles, ensuring stable pressure distribution across multiple circuits. This part is engineered to provide reliable pressure regulation and circuit isolation to maintain braking safety during operation.

303.02.0094 is the OE-equivalent of the KNORR-BREMSE AE 4427 4-circuit protection valve used in heavy commercial vehicle braking systems. This component features a specific port configuration including Port 1 (M22x1,5) and multiple M16x1,5 ports to ensure precise pneumatic control and compatibility with standard heavy vehicle hardware.

For the workshop technician, this valve offers precise pressure thresholds with an opening pressure of 7 BAR for ports 21 and 22, and 5,7 BAR for ports 23 and 24. The closing pressure is consistently maintained at 4,7 BAR across all secondary ports to ensure rapid response during system pressure drops. Regular inspection of the port seals and connection points is recommended during routine brake system maintenance.

Installation should be performed by qualified service professionals to ensure the integrity of the pneumatic circuits. Proper seating of the M-thread connections is essential for preventing air leaks in high-pressure environments.