Birelart Cylinder Master Cap

Summary: Why is this vital ?

This cap (or bellows) is not just a piece of rubber. He plays a crucial role:

1. Anti-contaminant barrier: It prevents track dust, sand and water to enter the body of the pump.

2. Protection of the axis: If dirt enter here, they mix with fat, creating an abrasive paste that will scratch the piston and destroy your internal seals.

3. Maintaining the lubricant: It keeps the clean fat inside the mechanism of the thrust rod.

- Technical specifications

-Tuto mounting: the good gesture

The assembly is simple, but requires finesse to not tear the rubber.

1. Disassembly: Remove the old rod or the holding circlip. Clean the accommodation with a clean cloth.

2. Inspection of the stem: Before replacing the cap, check that the thrust rod has no rust or bites. A damaged rod will "cut" the new interior cap.

3. Lubrication: Apply a very fine film silicone grease or lithium grease on the stem and inside the bellows. Caution: Do not use fat mineral grease, it can boost rubber.

4. Setting up: First look at the wide part on the body of the pump (make sure it is housed in its throat), then pass the narrow part on the rod. Check that it is not pinched.

💡 Michel's trick

"The cap is the health thermometer of your pump. The trick: If, when you remove the cap, you see brake fluid (not grease, but wet liquid) inside, it's not a good sign. This means that your internal piston seal (the primary seal) leaks and lets the fluid pass. My Pro Council: Replace the cap systematically if you see it's cracked or hardened. A cracked cap is the assurance of having a blocked or fleeing brake pump at the next output in the rain. "

❓ FAQ SEO (Frequently Asked Questions)

Q: Is it serious if the cap is a little torn ?

A: Yes, it's an open door to dust. As soon as the cap loses its tightness, your brake pump sucks dirt at each pedal stroke. This drastically reduces the life of internal joints.

Q: Can we use classic grease on it ?

A: No, the classic rolling grease is often incompatible with certain types of rubbers and can soften them or crack. Use silicone grease or specialized brake grease.

Q: Is the cap different between the 22SR model and old models Birel ? ?

A: Yes, the dimensions of the fixing groove may vary. It is best to check your pieces of parts to control the exact reference of the 22SR to avoid adjustment problems.

✅ Ready for your maintenance ?

The braking system is your only ally to take turns safely. To finalize your intervention:

• [Graisse silicone] (Indispensable for preserving rubber).

• [Chiffon propre] (To avoid impurity during reassembly).