303.02.0077 4-circuit protection valve
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303.02.0077 4-circuit protection valve — KNORR-BREMSE

303.02.0077

Summary

●Port 1: M22x1,5 ●Port 21: M16x1,5 ●Port 22: M16x1,5 ●Port 23: M16x1,5 ●Port 24: M16x1,5 ●Opening Pressure 21: 7 BAR ●Opening Pressure 22: 6,5 BAR ●Opening Pressure 23: 6,5 BAR ●Opening Pressure 24: 6,5 BAR ●Closing Pressure 21: 4,5 BAR ●Closing Pressure 22: 4,5 BAR ●Closing Pressure 23: 4,5 BAR ●Closing Pressure 24: 4,5 BAR

EAN Code8683457009363
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Description

The technical function of this component is to regulate and protect the pneumatic circuits within the braking system, ensuring precise pressure management across multiple lines. Designed with heavy-duty grade materials, it provides reliable operation for the vehicle's pneumatic control systems under demanding conditions.

303.02.0077 is the OE-equivalent of the KNORR-BREMSE AE 4178 4-circuit protection valve used in specialized heavy commercial vehicle braking systems. This part ensures seamless integration and maintains optimal pressure thresholds as specified by the original equipment standards.

Workshop technicians should ensure that all port connections (Port 1: M22x1,5 and Ports 21-24: M16x1,5) are properly seated and that the opening/closing pressures align with system requirements to prevent pneumatic failure. Regular inspection of the valve assembly is recommended during standard brake system maintenance to ensure consistent performance of the multi-circuit protection.

Technical Specifications

Port 1M22x1,5
Port 21M16x1,5
Port 22M16x1,5
Port 23M16x1,5
Port 24M16x1,5
Opening Pressure 217 BAR
Opening Pressure 226,5 BAR
Opening Pressure 236,5 BAR
Opening Pressure 246,5 BAR
Closing Pressure 214,5 BAR
Closing Pressure 224,5 BAR
Closing Pressure 234,5 BAR
Closing Pressure 244,5 BAR

Other OEMs

KNORR-BREMSE

  • AE 4178
  • AE4178

Related Products

Repair Kits

Vehicles Used

BrandModelEngine
KNORR-BREMSE

FAQ

Which OEM numbers are this part compatible with?
This product is a direct replacement for the KNORR-BREMSE AE 4178 code.
What are the thread specifications for the ports?
The unit features Port 1 with M22x1,5 and Ports 21, 22, 23, and 24 with M16x1,5 threads.
What are the opening pressure values for this valve?
The opening pressure for Port 21 is 7 BAR, while Ports 22, 23, and 24 are set at 6,5 BAR.
Is this part suitable for heavy commercial vehicle braking systems?
Yes, it is designed specifically for heavy commercial vehicle pneumatic brake system circuits.
What is the closing pressure for the circuit ports?
All four ports (Ports 21 through 24) have a closing pressure of 4,5 BAR.