Marsh Brothers M-03-1000-1 MASTER CYL KIT-KINGAIR/B1900D SUIT 90-380001-23

The **Marsh Brothers Aviation King Air Beech Brake Master Cylinder Upgrade/Repair Kit** (P/N **M-03-1000-1**) is a proactive solution designed to address leaks and typical O-ring failure modes at the brake master cylinder piston-rod seal. By replacing the traditional piston-rod O-ring and rod wiper with a proprietary **Thorseal® lip seal**, the kit helps increase the time between unscheduled maintenance events and reduce brake master cylinder maintenance costs. The Thorseal® is manufactured from Marsh Brothers’ proprietary **AeroLas™-Flex elastomeric polymer**, which provides improved low-pressure sealing and cold-weather performance. The kit contains the seals and hardware required to repair and upgrade a compatible King Air brake master cylinder. Installation aids, including a seal-compression ring, thread sleeve and push tube, are also supplied to assist with reassembly. The **piston is not included** in this kit. AeroLas™-Flex is not compatible with phosphate-ester hydraulic fluid, commercially known as **Skydrol**. Exposure to this fluid may damage the seals. ### Kit Contents | Item | MBA Part Number | Description | Quantity | OEM Cross-Reference P/N | |---:|---|---|---:|---| | 1 | AN316-5R | Rod-end jam nut | 1 | AN316-5R | | 2 | MS16625-1100 | Internal retaining ring | 1 | MS16625-1100 | | 3 | MBA-03-10000-1 | Piston-rod gland seal | 1 | A57G401 / AN6227B6 | | 4 | MS28775-117 | O-ring – static gland | 1 | 01-117 | | 5 | MS28775-210 | O-ring – piston head | 1 | 01-117 | | 6 | MS28774-019 | Back-up ring – piston head | 1 | N/A | | 7 | MS24665-132 | Cotter pin | 1 | AN380C2-2 | | 8 | MS16624-1037 | External retaining ring | 1 | N/A | --- ## Applications The **M-03-1000-1** kit is specifically designed for OEM brake master cylinder P/N **90-380001-23** installed on selected: - **Beechcraft King Air aircraft** - **Beechcraft 1900 series aircraft** - **Beechcraft Model 99 series aircraft** Compatibility depends on the aircraft model, installed brake master cylinder and applicable approved-model list. --- ## Why CJ Aerospace? CJ Aerospace supplies approved aviation components backed by technical knowledge and responsive customer support: - 🇦🇺 **Australian-owned and operated** - 📦 **Efficient Australia-wide supply and delivery support** - 🔧 **Technical guidance on part selection and compatibility** - ✈️ **Supporting aircraft operators, maintainers and aviation professionals** > ✉️ [Contact us at sales@cjaerospace.com.au](mailto:sales@cjaerospace.com.au) > Need help confirming compatibility with your aircraft or brake master cylinder? Our team is ready to assist.

- Applicable to OEM brake master cylinder P/N **90-380001-23** - Proprietary **Thorseal® piston-rod lip seal** - Thorseal® replaces the OEM piston-rod O-ring and rod wiper - Helps eliminate typical failure risks associated with traditional O-rings in dynamic sealing applications - AeroLas™-Flex elastomeric polymer provides improved low-pressure sealing performance - Improved cold-weather performance - Supports preventative brake master cylinder maintenance - Allows the compatible brake master cylinder to be repaired and upgraded - Installation tooling included: seal-compression ring, thread sleeve and push tube - Delivery documentation includes applicable STC certificates and a Transport Canada Form One authorised release certificate - Approved for eligible Canadian-, US- and Brazilian-registered aircraft