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303.02.0042 Compatible 4-Circuit Protection Valve

303.02.0042

Summary

This 4-circuit protection valve is engineered for heavy commercial vehicle brake systems, featuring M22x1.5 and M16x1.5 port configurations. It operates at a maximum pressure of 20 BAR, ensuring reliable pressure distribution across multiple circuits to maintain braking performance. Equivalent to OE Knorr-Bremse AE4611.

Product identifiers
EAN Code8683457005211
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Compatible OEM Codes

  • KNORR-BREMSE
    • II33856
    • AE 4611

Description

What does a protection valve do?

This protection valve plays a critical role in the pneumatic brake system by managing air pressure distribution across multiple independent circuits. By isolating pressure failures, it ensures that a leak in one circuit does not compromise the entire braking capability of the vehicle, providing high-strength component reliability for workshop technicians.

System compatibility and specifications

This component is compatible with Knorr-Bremse systems and is designed to handle operating pressures up to 12 BAR. It features specific opening pressures, such as 7.3 BAR for port 23 and 7 BAR for ports 21, 22, and 24, to maintain precise pneumatic control during heavy-duty operation.

Installation and maintenance guidance

Installation requires careful attention to the port sizes, specifically the M22x1.5 inlet and M16x1.5 outlets, to ensure a secure seal. Technicians should verify that all connection points are free of debris and that the closing pressure remains consistent at approximately 4.5 BAR across all circuits to ensure optimal system response.

Operational monitoring

Regular inspection of the valve ports and pressure settings is recommended during routine maintenance to prevent system imbalances.

OE cross-reference

303.02.0042 (4-circuit protection valve) is the equivalent of the Knorr-Bremse OE numbers. This part directly replaces Knorr-Bremse OE numbers AE4611, II33856.

Technical Specifications

Technical Specifications
Port 1M22x1,5
Port 21M16x1,5
Port 22M16x1,5
Port 23M16x1,5
Port 24M16x1,5
Operating Pressure12 BAR
Opening Pressure 217 BAR
Opening Pressure 227 BAR
Opening Pressure 237,3 BAR
Opening Pressure 247 BAR
Closing Pressure 214,5 BAR
Closing Pressure 224,5 BAR
Closing Pressure 234,5 BAR
Closing Pressure 244,5 BAR
PressureMAX 20 BAR

Other OEMs

KNORR-BREMSE

  • AE4611
  • II33856
  • AE 4611

Related Products

Compatible Vehicles

Compatible Vehicles
BrandModelModel TypeEngine
KNORR-BREMSE

FAQ

What is the function of a 4-circuit protection valve?
It manages air pressure across four separate circuits, ensuring that a leak in one area does not lead to a total loss of braking power in the vehicle's pneumatic system.
What are the technical port specifications for this valve?
The unit features a primary M22x1.5 port and four secondary ports with M16x1.5 threading to accommodate standard heavy commercial vehicle air lines.
What is the maximum operating pressure allowed?
This component is designed for use in systems with an operating pressure of up to 12 BAR, with a maximum structural pressure rating of 20 BAR.
How can I identify if the valve needs replacement?
Technicians should look for inconsistent closing pressures or air leaks at the M16x1.5 ports, which may indicate internal seal wear or mechanical fatigue.
What are the OE reference numbers of this part?
303.02.0042 directly replaces Knorr-Bremse OE numbers AE4611, II33856.