Mastercool 58490 Valve Core Remover/Installer Kit, Under-Pressure Service Kit
- The Mastercool 58490 Universal Kit lets technicians remove and install valve cores on R12 and R134a air conditioning systems while the system remains pressurized; it includes a built-in ball valve, multiple shaft types, and adapters to cover a wide range of valve core styles without discharging refrigerant.
- Features:
- Built-in stainless steel ball valve allows shutting off access port to contain refrigerant while changing valve core, reducing discharge and saving time.
- Universal compatibility with standard cores (0.210-36), JRA (M6 x 0.75), Eaton-style cores (8 mm & 10 mm), and GM large bore cores; suitable for both high-side and low-side service ports.
- Includes multiple connector types: 16 mm high-side R134a, 13 mm low-side R134a, 1/4 inch FL swivel connector; plus several shafts/assemblies for different valve core styles to adapt to many vehicle systems.
- Heavy-duty construction with brass body and hardened steel shafts; parts designed for repeated service under pressure; included molded box for organized transport.
- Includes:
- Valve core removal/installer assembly with built-in shut-off ball valve
- R134a high-side 16 mm connector
- R134a low-side 13 mm connector
- 1/4 inch FL swivel connector
- Standard valve core shaft assembly
- GM large bore valve core shaft assembly
- JRA R134a valve core shaft assembly
- Eaton R134a low-side valve core shaft assembly (8 mm thread)
- Eaton R134a high-side valve core shaft assembly (10 mm thread)
- Adapter 1/4 inch male x 3/16 inch female high-side GM/Ford
- Adapter 1/4 inch male x 1/8 inch female high-side Ford
- Molded carrying case
- Specifications:
- Manufacturer: Mastercool
- Part Number: 58490
- Measurement System : R12 and R134a automotive air conditioning systems
- Valve Core Types Supported: Standard, JRA (M6 x 0.75), Eaton style (8 mm & 10 mm), GM large bore cores
- Connector Sizes: 16 mm high-side, 13 mm low-side, 1/4 inch FL swivel; plus Ford/GM adapters as listed above
- Construction Material: Brass body, stainless steel ball valve parts, hardened steel shafts/adapters
- System Compatibility: Allows core replacement without losing refrigerant charge; useful in professional shops for both R12 and R134a; covers multiple valve core styles and service port designs on most passenger vehicles
- The Mastercool 58490 can also be referred to as Mastercool universal core remover/installer 58490, Mastercool under-pressure R134a valve core service kit, Mastercool valve core change kit standard/JRA/Eaton cores, and Mastercool R12/R134a valve core service tool set
Mastercool is a family-owned manufacturer of professional HVAC/R and automotive A/C service tools and equipment, including manifolds, gauges, vacuum pumps, recovery units, leak detectors, and fittings.
Q: Does using this kit require evacuating the A/C system first?
A: No, the built-in ball valve allows you to shut off the service port so you can remove and install the valve core without evacuating the refrigerant first.
Q: Which types of valve cores are covered by this kit?
A: It covers standard cores (0.210-36 thread), JRA (M6 x 0.75), Eaton-style cores with 8 mm and 10 mm threads, and GM large bore valve cores.
Q: Will this kit work on both the high-side and low-side service ports?
A: Yes, supplied connectors work with both high-side (16 mm) and low-side (13 mm) R134a service ports; additional adapters make it compatible with varied port designs.
