281865 EMERGENCY RELAY VALVE DUAL FUNCTION AIR BRAKE FITS 281860 281865RX

Ref. # Bendix 281865, H-30198

· System Type: Heavy Duty Air Brake System

· Valve Function: Emergency Relay / Service Relay

· Mounting Type: Frame-mounted air brake valve

· Material: High-strength aluminum alloy valve body

· Internal Components: Hardened steel and corrosion-resistant seals

· Operating Pressure Range: 70–120 PSI typical truck air system

· Port Configuration: Standard SAE air brake ports

· Control Type: Pneumatic air pressure-controlled relay valve

· Application: Trailer emergency brake control system

· Temperature Range: -40°F to 250°F operating range

· Installation Location: Trailer air brake control system

· Industry Standard: Compatible with DOT-compliant air brake systems

The dual-function design allows the valve to perform two essential operations:

· Emergency braking control when trailer supply air pressure is lost

· Relay function to provide faster brake application on the trailer axle system

By accelerating air delivery to the brake chambers, the relay valve improves brake response time, system safety, and braking efficiency under normal and emergency conditions.

This valve is made from carefully shaped aluminum and has strong internal seals, so it can handle the tough conditions of heavy-duty trucking, like shaking, temperature changes, and constant air pressure.

This replacement valve meets industry standards used across North American commercial truck and trailer braking systems.

Ideal for:

• Fleet maintenance shops

• Trailer repair facilities

• Truck service centers

• Independent diesel mechanics

• Pre-installed internal seals and components

• Ready for installation into air brake system

This part is utilized in air brake systems for heavy-duty trucks and trailers.

EBN281865N, 745-281865N

R955281865N Reference numbers are for identification purposes only.

Semi Trucks

· Freightliner

· Kenworth

· Peterbilt

· Volvo

· International

· Mack

· Western Star

Trailers

· Dry van trailers

· Flatbed trailers

· Refrigerated trailers

· Dump trailers

· Container chassis

Brake System Manufacturers

The brake system manufacturers are compatible with systems that utilize components similar to those used in Bendix style emergency relay valves and truck and trailer air brake relay valves.

· Bendix-style emergency relay valves

· Truck and trailer air brake relay valves

• Trailer brakes applying slowly

• Air pressure loss in trailer system

• Brakes locking unexpectedly

• Air leaks near valve body

• Delayed brake response

• Inconsistent brake pressure delivery

A faulty relay valve can affect braking response time and overall brake safety.

• Air brake system configuration

• Port layout and mounting style

• OEM part number reference

This valve replaces 281860/281865/281865X/281865RX-style valves used in many trailer brake systems.

Improper installation can cause:

• Brake system malfunction

• Air leaks

• Reduced braking performance

Installation should be performed by a qualified heavy-duty truck technician.

• Air pressure sealing integrity

• Proper valve actuation

• Internal component alignment

• Manufacturing quality control

Designed to meet heavy duty trucking reliability requirements.

• Inspect air lines for contamination

• Replace damaged air fittings

• Verify air pressure system operation

• Check brake chamber response time

• Inspect trailer supply and service lines

Proper system maintenance improves brake response and vehicle safety.

Length: 8 in

Width: 6 in

Height: 4 in