Description
Bendix R-12 service relay valve (P/N 103009) used on long-wheelbase tractors and trailers to apply and release rear-axle service brakes quickly. With a 4 PSI crack pressure, two 3/4″-14 NPT supply ports, two 1/2″-14 NPT delivery ports, and a 1/4″-18 NPT control port, the 103009 is the standard high-capacity relay for class 6-8 air brake systems. Replaces Bendix 103009N, OR103009, OR103009X, Haldex KN28140, and Meritor R955103009N.
Signs You Need a New Relay Valve
- Slow brake application or release at the rear axle
- Continuous air leak from the exhaust port with brakes released
- Uneven brake force or pulling under hard application
- Air pressure drop in the rear service circuit during stops
- Brake compounding or “drag” after release
Specifications
| Manufacturer | Bendix |
|---|---|
| Part Number | 103009 |
| Part Type | Service Relay Valve |
| Model | R-12 |
| Crack Pressure | 4.0 PSI |
| Supply Ports | (2) 3/4″-14 NPT |
| Delivery Ports | (2) 1/2″-14 NPT |
| Control Port | 1/4″-18 NPT |
| Exhaust Port | Dust Shield |
| Operating Temperature | -40°F to 200°F |
Cross References
This part replaces or is equivalent to the following part numbers:
- Bendix: 103009, 103009N, OR103009, OR103009X
- Meritor: R955103009N
- Haldex: KN28140, KN28140N, 103009RX
- Navistar: FLTBV3009
- Euclid: EBN103009N
- PAI: EM35960
- Automann: 170.103009
- Wheeler Fit: 2411-103009N
Applications
This relay valve fits a wide range of long-wheelbase Class 6-8 trucks, tractors, and trailers running standard FMVSS-121 air brake systems. Representative platforms include:
- Freightliner Cascadia, Columbia, FLD, Century, M2, Argosy
- Kenworth T600, T660, T680, T800, W900
- Peterbilt 379, 386, 387, 389, 567, 579
- International 9200, 9400, ProStar, LoneStar, LT
- Mack CH, CHU, Pinnacle, Granite, Anthem
- Volvo VNL, VNM, VHD
- Western Star 4700, 4900, 5700, 5900
- Trailers and tankers using rear-axle service relay control
Verify port sizes, crack pressure, and mounting orientation against your existing valve before ordering. R-12 valves are produced in multiple port-orientation variants — confirm horizontal vs. vertical delivery to match your plumbing.
