303.02.0034 4-Circuit Protection Valve — WABCO Compatible

What does a 4-circuit protection valve do?

This 4-circuit protection valve is a critical component within the pneumatic brake system of heavy commercial vehicles. It serves to distribute supply pressure to four independent circuits—typically covering front brakes, rear brakes, spring brakes, and trailer supply—while isolating any circuit that experiences a pressure loss to maintain overall braking safety.

Vehicle and engine compatibility

This component is compatible with Volvo models such as FH12, FH13, FM series, and VNL engines like D13 and D16. It is also fitted to Renault Trucks Kerax and Magnum models, as well as Mack Granite and Pinnacle trucks. For optimal performance, ensure the valve matches the specific circuit requirements of the vehicle's air processing assembly.

Technical specifications and installation

The unit features specific port configurations including an M22x1,5 inlet and M16x1,5 outlets (Ports 12, 21, 22, 11, 23, and 24). Technicians should verify that opening pressures—such as 6.3 BAR for ports 21 and 22 or 5.8 BAR for ports 23 and 24—align with the original equipment specifications during installation to ensure correct braking sequence.

Maintenance and selection guidance

Regular inspection of the pneumatic lines and connection points is recommended to prevent leaks. Consult your authorized distributor to confirm exact fitment for your specific vehicle chassis.

OE cross-reference

303.02.0034 (4-circuit protection valve) is the equivalent of the DAF, Volvo and WABCO OE numbers. This part directly replaces DAF OE number 1528375. It also replaces Volvo OE numbers 20382309, 20452151, 20716313, 20755195, 21225479 and WABCO OE numbers 9347141400, 9347147400.