303.02.0077 Compatible 4-Circuit Protection Valve
303.02.0077
Summary
This 4-circuit protection valve is engineered for heavy commercial vehicle brake systems. Featuring M22x1.5 and M16x1.5 port configurations, it provides precise pressure regulation with specific opening pressures of 7 BAR and 6.5 BAR to ensure reliable pneumatic performance. Equivalent to OE Knorr-Bremse AE4178.
| EAN Code | 8683457009363 |
|---|
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Compatible OEM Codes
-
KNORR-BREMSE
- AE 4178
Description
What does a protection valve do?
This protection valve plays a critical role in the pneumatic brake system by dividing the air supply into multiple circuits, ensuring that a leak in one area does not compromise the entire braking capability. It is constructed from heavy-duty grade materials to withstand the constant pressure fluctuations and harsh environments typical of heavy commercial vehicle operations.Compatibility and port specifications
The component is designed to be compatible with Knorr-Bremse systems and meets the rigorous demands of professional workshop technicians. It features specific port sizes including M22x1.5 for the primary inlet and M16x1.5 for the subsequent outlets, ensuring a secure and airtight connection within the air brake circuit.Installation and maintenance
For optimal performance, technicians should verify that the opening pressures—ranging from 6.5 BAR to 7 BAR—and closing pressures of 4.5 BAR align with the vehicle's specific pneumatic requirements during installation. Regular inspection of the connection points is recommended to maintain system integrity.System reliability guidance
Consult your authorized distributor to ensure this part matches the specific technical requirements of your fleet's braking architecture.OE cross-reference
303.02.0077 (4-circuit protection valve) is the equivalent of the Knorr-Bremse OE number. This part directly replaces Knorr-Bremse OE number AE4178.Technical Specifications
| 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 |
Other OEMs
KNORR-BREMSE
- AE4178
- AE 4178
Related Products
Repair Kits
Compatible Vehicles
| Brand | Model | Model Type | Engine |
|---|---|---|---|
| KNORR-BREMSE |
FAQ
What is the function of a 4-circuit protection valve?
It divides the air supply into four independent circuits, preventing a loss of pressure in one circuit from affecting the others, thereby maintaining braking safety.
What are the port sizes for this component?
This valve features one M22x1.5 port and four M16x1.5 ports to facilitate standard pneumatic connections.
How do I know if the pressure settings are correct?
The unit operates with an opening pressure of 7 BAR on Port 21 and 6.5 BAR on Ports 22, 23, and 24, with a closing pressure of 4.5 BAR across all outlets.
What should I check during installation?
Ensure all M22x1.5 and M16x1.5 connections are tightened correctly to prevent air leaks that could impact braking performance.
What are the OE reference numbers of this part?
303.02.0077 directly replaces Knorr-Bremse OE number AE4178.