Marsh Brothers Aviation M-03-1000-1 - King Air Beech Brake Master Cylinder Kit - OEM 90-380001-23
Increase the operational reliability and performance of your aircraft's braking system with the Marsh Brothers Brake Master Cylinder Upgrade/Repair Kit. This FAA and TCCA-approved solution addresses a common issue with brake master cylinders – leaking piston rod seals caused by wear and tear on traditional O-rings.
Key Features
- Upgraded Piston Rod Seal: Marsh Brothers replaces the O-ring with a specially designed lip seal constructed from a high-performance polymer. This material offers superior wear resistance and sealing capabilities compared to the original equipment manufacturer (OEM) design.
- Enhanced Cold Weather Performance: The upgraded lip seal maintains greater flexibility at low temperatures, eliminating leaks that can occur with O-rings when the aircraft is parked in cold environments.
- Complete Rebuild Kit: The kit includes everything needed for a comprehensive master cylinder rebuild, including tooling, seals, a thread sleeve for protecting the inner lip during installation, a push tube (installation tool), a cotter pin, washers, static O-rings, and a circlip.
- Reduced Downtime: By proactively addressing potential leaks and wear, the Marsh Brothers Brake Master Cylinder Upgrade/Repair Kit helps minimize unscheduled maintenance occurrences, keeping your aircraft operational.
OEM Part #: M-03-1000-1
| Alternate Models | |
|---|---|
| M-03-1000-1 | OEM Part # |
| General Information | |
|---|---|
| Part # | M-03-1000-1 |
| Manufacturer | Marsh Brothers Aviation |
| Shipping Information | |
|---|---|
| Product Weight | 0.5 lbs. |
| Product Dimensions | 7 x 5 x 3 in. |
| Schedule B | 8807300010 |
| ECCN | 9A991.d |
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AIRCRAFT COMPATIBILITY
| Compatible Aircraft* | |
|---|---|
| Hawker Beechcraft | 300 - King Air , Beech 1900 , King Air |
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QUESTIONS & ANSWERS
The kit is compatible with OEM part numbers 90-380001-23, 90-380001-29, and 90-380001-33. These are specific to certain King Air and Beech 1900 brake master cylinders, so it’s important to verify your part number before installation.
Yes, the kit is approved by multiple aviation authorities: the FAA (SAO4634NY), Transport Canada (SA21-5), and ANAC Brazil (2024S08-04). These Supplemental Type Certificates (STCs) allow legal installation in U.S., Canadian, and Brazilian-registered aircraft.
Yes, the proprietary Thorseal® included in the kit replaces both the OEM O-ring and the rod wiper. This helps reduce leak points and simplifies the assembly while improving performance.
The piston rod seal is made from AeroLas™-Flex, a proprietary elastomeric polymer developed by Marsh Brothers. This material offers superior cold-weather flexibility and enhanced wear resistance compared to traditional rubber seals.
No, AeroLas™-Flex is not compatible with phosphate ester hydraulic fluids, such as Skydrol. Using this seal with Skydrol will cause degradation and failure, so it's important to verify your fluid type before installation.
No, the piston is not included in the Marsh Brothers King Air Brake Master Cylinder Kit. If the piston is damaged or worn, it must be sourced separately before completing the upgrade.
