Nobody pays much attention to the piston rod seal in their brake master cylinder until it starts

leaking. Even when it does leak it won't cause much more than carpet damage, unless you

ignore it. When your brake master cylinder requires repair due to leakage or you want to take

a proactive approach, the Marsh Brothers’ Brake Master Cylinder upgrade/repair kit is the solution

that will fix it once and for all. Like all Marsh Brothers products, our glands and seals are developed

to last for the long haul.

Installation of the Marsh Brothers brake master piston rod seal offers the opportunity to practice preventative maintenance, by eliminating the risks associated with the typical failure modes of traditional O-rings used in the dynamic seal applications.

The Marsh Brothers Aviation Bonanza/Baron brake master cylinder upgrade kit contains all of the hardware to repair/upgrade your Bonanza/Baron brake master cylinder. Additionally, the kit also includes tooling to aid in the re-assembly. The piston rod seal (AeroLas™-Flex) provided is a Marsh Brothers Aviation proprietary lip seal design and is manufactured from a proprietary elastomeric polymer. The Marsh Brothers Aviation Thorseal® replaces both the OEM O-ring and rod wiper. The kit also includes installation instructions, instructions for continuing airworthiness and an authorized release certificate.

Caution: Thorseal® is made from Marsh Brothers proprietary material known as AeroLas™-Flex. AeroLas™-Flex is not compatible with phosphate ester hydraulic fluid, commercially known as Skydrol. Exposure to phosphate ester hydraulic fluid contamination will damage the seals.

Note: The Piston is not included in this kit.