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Gasket set for master cylinder model 6+7
Gasket set for master cylinder model 6+7 Gasket set for master cylinder model 3+4 Gasket set for master cylinder model 6+7

TOST Gasket Set

Sale Price: $30.00

SKU: 6119, 6126

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Detailed Description

TOST Gasket Set

General Description

TOST Gasket Set for Master Cylinder 3&4 and 6&7.

History of TOST

TOST has more than 60 years of experience in the development and manufacturing of aviation safety equipment. It's a family business – run in the fourth generation – they stick to the motto: Conserving the well–proven system – Developing forward.
The cornerstones of their corporate policy are:
Customer satisfaction is their highest goal. The customer is the king – he should like to come back – and not like to send the product back.
Since 1969 TOST holds a LBA approval as Design and Production Organization. (LBA= German Aviation Authorities). In the meantime, all approvals are issued by the EASA. In yearly audits through the aviation authorities, the compliance with quality standards is checked and kept record of. Over and above those official regulations, they live the quality thought in their every–day work.
Modern manufacturing techniques, economical resource management and the long lifetime of TOST products are their contribution to the protection of the environment. Gliding is an ecologically friendly sport.
Long standing relations to their customers, suppliers and employees stand for the continuity in their company.

TOST Master Cylinder

Overhauling and Replacing Master Cylinder Parts

If the master brake cylinder is not functioning properly, the seal rings (gasket) must be replaced.

  1. Drain brake fluid reservoir.
  2. Unscrew brake pipe and plug up hose ends.
  3. Dismantle operating lever A.
  4. – Type 3 and 4: Dismantle seal collar C with operating arm.
    – Type 6 and 7: Press in piston B completely to remove washer E from the inside of the bore.
  5. Pull out piston B by hand.
  6. Turn piston spring F clockwise to loosen it.
  7. Remove the old seal rings by hand. Do not use metal tools and take care not to damage the piston.
  8. Clean all arts with alcohol and check them for damage caused by wear or by improper usage or handling.
  9. Finally, brush parts with brake fluid.
  10. Install new seal rings G and H, see sketch for position. Since July 2012 seal ring H is a two–part seal. First position the o–ring in the groove, second slide the seal onto the o–ring.
  11. Grease sliding parts and rubber parts with “ATE” brake cylinder paste before assembly.
  12. – Type 3 and 4: Install piston, taking special care of cup leather.
    – Type 6 and 7: Place seal D and washer E on 10 mm diameter of piston and push in together.
    Press washer E into place with pipe tool (25Ø x 2.5 wall x 60 long).

Use above dropdown box for TOST Gasket Set selection and final price.

General Maintenance

  1. Regular Operating Checks

  2. • Regularly check the brake fluid level in the reservoir. The level must never drop more than 10 mm below the maximum fill level. For topping up use only brake fluid specified for the system. Do not open the brake fluid can until just before topping up.
    Do not use old brake fluid for topping up!

  3. Annual Checks

  4. • Check wear on dist pads and replace if wear has exceeded 2.5 mm.
    • Check disk surfaces for deep grooves and if necessary install new genuine brake disks. Disk thickness (new disk) = 5 mm, wear limit = 4.3 mm
    • Completely drain brake system, fill with new brake fluid and bleed brake system as described on this page.
    Never use mineral oil or grease!


  1. Rules for disassembling any part of the disk brake system
    • Before dismantling any parts thoroughly clean the outside of the brake system with alcohol and a clean brush.
    • Unscrew hydraulic pipes and carefully close off pipe end with stoppers to prevent dirt from getting into the pipes.
    • Clean all dismantled parts, including those made of rubber, with alcohol using a fine brush and let them dry in a dust–free area.
    • Using other cleaning agents such as petrol, diesel, petroleum or trichloroethane is strictly prohibited, as these will irreparably damage the rubber parts!
    • Handle precision metal parts (alloys) carefully to avoid damage.
    • Brush cleaned parts with brake fluid to inhibit corrosion.
    • Grease sliding parts and rubber parts with “ATE” brake cylinder paste before assembly.
  2. Description
    • The master cylinders are die–cast alloy housings, comprising the reservoir that holds the brake fluid, the brake lever mechanism and the cylinder.
    • The hydraulic piston has two seal seats, one at the front for holding the pressure collar, one at he back for holding the guide seal (since July 2012 a two–part seal us used as spare part). The top of the piston is milled to seat the return spring. On the rear there is a pan–shaped recess (type 3 and 4) into which the operating arm off the brake lever fits.
    • The exact position of the piston is determined by the setting of the manual brake.
    • To unsure that the hydraulic circuit is always supplied with brake fluid, the slack of the manual brake lever (travel between rest and working position) must be 3 to 4 degrees.
    • The master cylinder must be mounted in such a way that it is always above the brake yoke even under unfavorable operating conditions.

Filling or bleeding the hydraulic system is simpler from below using a TOST brake fluid gun or with TOST vacuum filling and bleeding pump.

Topping up Brake Fluid in Disk Brake Systems

  1. Loosen bleeding screw on brake yoke by one turn.
  2. Fill master brake cylinder reservoir with brake fluid and pull manual brake lever repeatedly full travel until brake fluid starts to flow through the bleeding screw on the brake assembly.
  3. Tighten bleeding screw.
  4. Continue to operate the manual brake lever slowly until a distinct shortening in the travel of the brake lever is observed.

Bleeding the Hydraulic Disk Brake System

  1. Pull manual brake lever.
  2. Slowly loosen and re–tighten bleeding screw before reaching full travel with the manual brake lever.
  3. Repeat bleeding process until the brake fluid flowing through the bleeding screw is completely free of bubbles.
  4. Fill brake fluid reservoir to about ¾ of total capacity and carefully replace closure cap.

Why Buy From Us?

Wings & Wheels has been serving the sport aviation and soaring community for more than 20 years.  We have the largest and most comprehensive inventory of sailplane and soaring supplies.  Nearly everything you find here is in stock and can ship the same day.  We are here for aviators, businesses, mechanics and government.  Our goal is to fulfill your order promptly and as conveniently as our resources allow.

Wings & Wheels is proud to be the American representative for HpH Ltd, producer of the finest quality 304 sailplanes.

Our staff has over 8,000 hours of flying experience in gliders and airplanes. Wings & Wheels is staffed by Sean, Garret, Miki, Matt and Linda. You will have a friendly voice pick up when you call. Our staff is trained to promptly take your orders and ship your products.

Shipping Information

Same Day Shipping

Orders placed by 3:00 pm PST Monday-Friday for “off-the-shelf“, in-stock items are normally shipped same day by UPS.  Although we stock the vast majority of the items on our online store, we cannot assure that they will all be on hand at all times. We ship every order as quickly as possible, and in the event of a delay, be assured that we are working hard to get your order shipped promptly. Due to order volume during holidays, we cannot guarantee that all orders placed can ship on the day after the holiday closure. 

Orders for special cut products may take a few days to ship depending on order volume. Special order products ship based on the lead times of each manufacturer. 

Shipping Service

UPS LogoUPS Shipping

UPS orders will need to be placed before 4:00 pm EST and 4:00 pm PST Monday-Friday to ship out the same business day.  We apply UPS retail rates to calculate shipping costs.  Packages may not qualify for actual wieight due to size.  If dimensional weight is applied by UPS your shipping & packing rate will be adjusted.  Packages are only insured aganst theft if signature delivery is accepted.  Request signature delivery.


Priority Mail & 1st Class order has to be placed by 11am. We will use the flat rate box service if your parts fit in the box and the service cost is less than USPS Priority Mail. USPS may not always have tracking information available.  If you request lower cost USPS shipping you agree to accept all responsibility for lost, stolen and damaged packages.

Delivery Timing

UPS Ground Delivery

USPS Delivery Timing

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