Description
WM318-G - RATIO RELAY VALVE (112201)
PART NUMBER(S):
Fleet Products: WM318-G | Replaces OE: Williams Controls: 112201, WM-318-A, WM318A | Automann: 170.112201 | Haldex: 90054170 | Rockwell: R986038 | Tectran: TEC-WM318A, TECWM318A, WM318ATEC | Meritor: R955WM318, R986038, R986038.ZX
DESCRIPTION:
Model: Williams Controls WM318 Ratio Relay Valve
Vehicles: Heavy-duty tractor-trailer air brake system configurations
• Valve Type: Three-way compensating, pilot-pressure-operated ratio relay valve
• No. of Ports: 3
• Port Size: Three 1/4" NPT ports
• Adjustable Pressure Ratio: 1.3:1 to 0.8:1 output-to-input
• Crack Pressure: 1.5 PSI with 100 PSI supply pressure
• Maximum Operating Pressure: 150 PSI
• Operating Temperature Range: -20°F to 200°F
• Function: Modulates delivery pressure in proportion to pilot pressure
Applications:
Designed for compatible tractor-trailer air brake systems requiring adjustable proportional control between pilot and delivery pressure. It is typically replaced when pressure balance becomes inconsistent, the valve leaks, or the required output-to-input pressure ratio can no longer be maintained.
CROSS-REFERENCE(S):
15169, TC WM318A, TCWM318A, MERR986038, TDAR986038, AC025, A12502035, U27WM318A, WIL 112201, 112201X, TURA12502035, WM318AX, TURA12502-035, A12502-035, WIMWM318A, 3945114, AC295
A cross-reference listing means this part may be a suitable replacement for the listed part numbers. Always verify fitment before installation.
IMPORTANT INSTALLATION NOTES:
✔ Confirm the required output-to-input pressure ratio before adjusting or installing the valve.
✔ Connect all three 1/4" NPT ports according to the approved air-system diagram.
✔ Install only in an approved ratio-relay or tractor-protection application.
✔ Apply air-system-compatible sealant without allowing sealant to enter the ports.
✔ Do not exceed 150 PSI; leak-test and verify pressure balance after installation.
Warranty Information
