Description
065146-G – BOBTAIL VALVE
PART NUMBER(S):
Fleet Products: 065146-G, 065146
OE: 65146, BP-R1, H065146
Automann:
DESCRIPTION:
Model: Bobtail Brake Proportioning Relay Valve
Vehicles: Designed for tractor (bobtail) configurations in heavy-duty trucks
• Supply Port: 1/2" NPT
• Delivery Ports: 2 × 3/8" FPT (side), 2 × 3/8" FPT (bottom)
• Control Port: 1/8" NPT
• Service Port: 1/4" NPT
• Crack Pressure: 5.5 PSI
• Actuation Type: Pneumatic, air-actuated relay/proportioning valve
• Material: Die-cast aluminum housing
• Operating Temperature Range: –40°F to +200°F (–40°C to +93°C)
• Mounting: Standard slotted mount (0.40" × 0.96" slots x4), bracket included in box
• Weight: Approx. 2.4 lbs (varies by configuration)
• Performance: Speeds up brake application/release time and regulates pressure for unladen braking (bobtail operation)
• Special Features:
– Dual-function relay + proportioning operation
– Hydraulic lock-out feature to prevent excessive brake pressure in bobtail mode
– Reduces stopping distances when tractor is not pulling a trailer
– Direct replacement for Bendix BP-R1
– Superseded by Bendix 65146N
Applications:
Used exclusively on tractors operating in bobtail mode (no trailer attached). Prevents over-braking during unloaded conditions and ensures proper air pressure balance in the brake system. Commonly installed on Freightliner, Mack, Peterbilt, Volvo, and other Class 7–8 commercial tractors.
CROSS-REFERENCE(S):
065146, 65146, ROY065146, 175065146, BEN065146, BP-R1, H065146, E-BN065146X, 14QK3116M, 14QK493M, 1660846C91, 1660846C92, 21010744, 21067501, 21155033, 21436094, 3558089C1, 3558089C2, 3558089C3, 3558989C1, 3558989C2, 3868266C1, 65146N, 83101, 85925, 859256514621010000, A85925, AMS600163, AMS65146, AMS660238, EM56880, M85925, R955065146N, S-C518, 106931, 681-4291-344A cross-reference listing means this part may be a compatible replacement for these part numbers based on OEM or distributor data.
IMPORTANT INSTALLATION NOTES:
✔ Designed for tractor (bobtail) applications only – do not use on trailers
✔ Ensure correct orientation of delivery ports (side vs. bottom) during installation
✔ Inspect crack pressure rating (5.5 PSI) before installation; variants exist
✔ Mount using included bracket or existing relay valve slots (0.40" × 0.96")
✔ Verify all NPT fittings for air-tight seal; torque per OEM air brake specs
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