Product Description
The Bendix 800534 ST-4 Safety Relief Valve is a heavy-duty pressure protection component designed for compatible commercial vehicle air compressors. Featuring a factory-set 250 PSI opening pressure and metric M16 x 1.5 straight-thread O-ring connection, this valve helps protect the compressor from excessive pressure that could damage internal components or the cylinder head.
Designed for select Bendix BA-921 air compressor configurations, the 800534 provides automatic pressure relief if compressor discharge pressure rises beyond the specified operating limit. Its spring-loaded design allows the valve to remain closed during normal operation and release compressed air when excessive pressure is detected.
Manufactured using durable brass and stainless steel components, the ST-4 safety valve provides corrosion resistance and reliable operation in demanding commercial vehicle environments.
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Genuine Bendix ST-4 safety relief valve
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Manufacturer Part Number: 800534
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Factory-set opening pressure: 250 PSI ± 10 PSI
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Metric M16 x 1.5 straight-thread O-ring connection
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M16 x 1.5-6H thread specification
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Straight Thread O-Ring Port (STORP) design
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Hex size: 7/8 inch
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Two exhaust openings
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Approximate exhaust opening diameter: 0.281 inch
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Spring-loaded automatic pressure relief operation
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Nonadjustable factory pressure setting
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Brass and stainless steel construction
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Operating temperature range: -40°F to 250°F
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Designed for compatible Bendix BA-921 compressors
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Helps prevent compressor damage caused by excessive discharge pressure
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Suitable for commercial truck air brake compressor maintenance
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Compact, corrosion-resistant construction
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New replacement safety valve
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Sold individually
The Bendix 800534 is designed for certain older BA-921 air compressor cylinder heads equipped with an M16 metric safety valve port. The valve is installed in the appropriate compressor cylinder head opening to help protect against excessive discharge pressure, including pressure buildup caused by restricted or blocked discharge lines.
Bendix later standardized new BA-921 compressor designs around a smaller 1/4-inch safety valve connection. Consequently, the 800534 should not be assumed to fit every BA-921 compressor.
Before ordering, verify the original valve part number, metric thread size, O-ring sealing configuration, and required pressure setting. This valve is not interchangeable with standard NPT-threaded safety valves or versions using different straight-thread connections.
If the safety valve repeatedly opens during operation, inspect the compressor discharge system and related air brake components for restrictions or other malfunctions. The safety valve is a protective device and should not be used to regulate normal operating pressure.
Important product distinction: Bendix 800534 uses an M16 x 1.5 metric straight-thread O-ring connection, not a 1/2-inch NPT fitting.
The following Bendix ST-4 valves have the same nominal 250 PSI pressure setting but different connection sizes:
|
Part Number |
Thread Size |
|---|---|
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800534 |
M16 x 1.5 O-ring |
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801116 |
7/8"-14 UNF O-ring |
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800533 |
3/4"-16 UNF |
|
800154 |
1/2"-14 NPT |
These valves should not be substituted for one another without confirming the compressor's port configuration
