Description
Power Products 110500P aftermarket spring brake priority valve replaces Haldex 110500/110500X, Bendix K025778 (SRC-7000), and Sealco 110500X on FMVSS-121 trailer air-brake systems. The valve supplies air to the spring-brake chambers first to release the parking brakes, then opens an internal pressure-protection check at approximately 80 psi to fill the trailer reservoir, preventing brake compounding during a breakaway or supply-line failure.
Signs You Need a New Spring Brake Priority Valve
- Spring brakes fail to release when supply air is restored
- Trailer reservoir fills before spring brakes release
- Brake compounding (service + spring) during emergency application
- Audible air leak from the valve body or exhaust port
- Spring brakes drag at low system pressure
Specifications
| Manufacturer | Power Products |
|---|---|
| Part Number | 110500P |
| Part Type | Trailer Spring Brake Priority Valve |
| Application | FMVSS-121 air-brake trailers |
| Supply Port | 3/8″ NPT |
| Control Port | 3/8″ NPT |
| Reservoir Port | 1/2″ NPT |
| Delivery Ports | 3/8″ NPT (2) |
| Reservoir Charge Pressure | ~80 psi |
Cross References
This valve replaces or is equivalent to the following part numbers:
- Haldex: 110500, 110500X
- Bendix: K025778 (SRC-7000)
- Sealco: 110500X, SEA110500
- Meritor: RSL110500
- Euclid: E-SL110500
- Dayton Parts: AV110500
- Fontaine: 55710035
- Freightliner: BWK025778, HDX110500, HDX110500X, TAC51301
- Tramec Sloan: 51301
- Triangle Springs: TRA51301
- World American: WA110500
Applications
This priority valve is used on the trailer air-brake circuit of FMVSS-121 compliant trailers, including:
- Heavy-duty highway semi-trailers (vans, flatbeds, tankers, reefers)
- Spread-axle and tandem-axle trailers using spring-brake parking actuators
- Converter-dolly air-brake systems
Verify port sizes and chassis layout before installation. Match the existing valve’s plumbing — supply, control, and delivery threads must align.
