Full description of the product (H1: sealing cup for FREELINE master cylinder 25 x 30 x 2 mm - Birel Art)

The fREELINE BRAKE CUP (dimensions 25 x 30 x 2 mm) is a high precision replacement hydraulic component of origin manufacturer (Original Freeline / Birel Art). It is designed to ensure absolute internal sealing and pressurizing the circuit at the cylinder master piston on the group's competition chassis Birel ART.

This cup (or specific lip seal) displays an inside diameter of 25 mm, an outside diameter of 30 mm and a thickness / height of 2 mm. Its technical profile is specially molded to evade under the pressure of the brake fluid, ensuring that no internal leakage occurs when the driver crushes the pedal. Made in a high-end elastomer resistant to chemical aggressions of competitive fluids, it maintains a reactivity of instantaneous and constant pedal, handle after handle.

Technical characteristics:

• Inner diameter: 25 mm

• Outside diameter: 30 mm

• Thickness / height: 2 mm

• Part type: Pressure lip seal (cup)

• Location: Master Cylinder Brake Piston

• Chassis compatibility: Birel Art, CL Kart (Charles Leclerc Racing), RicCiardo Kart, Kubica Kart

• Origin: FREELINE Certified Certified Part

- 3. Tip in Michel (the corner of the expert)

* "Hi Surgical Brake Aces! The 25x30x2 mm cup, it's it that creates the pressure in your brake circuit. If your pedal becomes mole, that it sinks to the floor during braking but that you do not see any external leaks on the Chassis, look for: it is the internal cup of the master cylinder that is returned or worn. The liquid passes" through "instead of being pushed towards the caliper.

My old mechanic trick for perfect mounting: attention to the sense of lip and lubrication required !

A cup has a specific editing direction: the hollow part (the open lip) must always be pressure oriented, that is to say to the bottom of the master cylinder where the liquid is compressed. If you ride it upside down, you will not have any pressure at the pedal.

Before reinserting the piston with its new cup into the master cylinder body, clean the bore thoroughly to eliminate impurities. Soak the clean brake fluid cup (dot 4 or dot 5.1 according to your system). Never force through to get it home, help a small mounting cone or go very slowly with your fingers to cut the edge of the rubber lip on the input thread. A joint cut to assembly, it's a master cylinder to reopen direct! "*

- 4. The replacement guide: step by step

- 5. SEO FAQ (Frequently Asked Questions)

Q: Does this 25x30x2 mm cup suit it for the inside of the brake caliper ?

A: Not. This cup is specifically dimensioned for the control piston of the master cylinder (which sends the pressure). The brake calipers (which receive the pressure around the wheel pistons) have square profiles or different diameters (usually 22, 24 or 32 mm at FREELINE).

Q: Can we use standard grease to facilitate the mounting of this cup ?

A: Absolutely not! Mineral or universal fats alter, swell and destroy the rubber of brake cups in a few hours. Use only clean brake fluid identical to that of your circuit, or special mounting grease for hydraulic braking circuits.

Q: Is it necessary to replace the spring of the master cylinder at the same time as the cup ?

A: This is not mandatory if the spring is in perfect condition and retains its original voltage. However, for optimal rehabilitation, it is advisable to check the condition of the piston and the internal walls of the master cylinder. If the bore is scratched, the change of cup will not suffice to guarantee the tightness.