Baron Brake Master Cylinder Upgrade/Repair Kit


Category: Baron

Type: Kit

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 Baron brake master cylinder upgrade kit contains all of the hardware to repair/upgrade your 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.

Note: The Piston is not included in this kit.

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.

This kit does not fit brake master cylinders manufactured by Gerdes or Paramount.

    • Piston Rod Lip Seal eliminates risk of typical failure modes associated with traditional O-rings used in dynamic applications.
    • The proprietary elastomeric polymer offers improved lower pressure sealing performance and overall cold weather performance.
    • Installation Tooling included - Seal compression ring, thread sleeve, and push tube.
    • Delivery documentation includes copies of all STC certificates and a Transport Canada Form One (authorized release certificate) to keep your logbook up-to-date.
    • Applicable to OEM P/N 96-380034-25 series brake master cylinders manufactured by Commercial Aircraft Corp.
    • NOTE: This kit may fit other OEM brake master cylinder part numbers. Please contact customer service for further details.
    • Approved for installation in Canadian Registered aircraft by Transport Canada Supplemental Type Certificate No. SA21-5 and US Registered aircraft by FAA Supplemental Type Certificate SAO4634NY (FAA)
    • Supplemental Type Certificate
    • FAA Supplemental Type Certificate
    • FAA Approved Models List
      Supplemental Type Certificate

      Bonanza Models

      Baron Models 

      TCCA: SA21-5

      FAA: SAO4634NY 


      35 E55
      A35 E55A
      B35 D55
      C35 D55A
      D35 56TC
      E35 58
      F35 58A
      G35 58P
      35R 58PA
      TCCA: SA21-5 FAA: SAO4634NY  35-33 58TC
      35-A33 58TCA
      35-B33 G58
      35-C33 95
      35-C33A 95-55
      36 95-A55
      A36 95-B55
      A36TC 95-B55A
      B36TC 95-B55B
      E33 95-C55
      E33A 95-C55A
      E33C A56TC
      F33 B95
      F33A B95A
      F33C D95A
      G33 E95

      Kit Content Picture

      Note: The Piston is not included in this kit.

      Item#  MBA Part # Description Quantity OEM Cross Reference Part #
      1 AN316-5R NUT ROD END JAM 1 AN316-5R
      2 MS16625-1100 INTERNAL RETAINING RING 1 MS16625-1100
      3 MBA-03-10000 PISTON ROD GLAND SEAL 1 A57G401 / AN6227B6
      4 MS28775-117 O-RING (STATIC GLAND) 1 AN6227B11
      5 MS28775-111 O-RING (PISTON HEAD) 1 AN6227B9
      6 MS28774-013 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


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