Summary: Why is this spring critical?
Although it is a simple room, the internal spring of the 22SR pump filled a major safety function:
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Return of the piston: It guarantees that the piston returns to the "rest" position after each braking. If the piston does not return completely, the circuit does not fulfill correctly by the tank, creating a soft pedal or braking that "drag" (drives that heat).
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Maintaining pressure: It ensures a constant pre-load for the joints (cups) remain in place.
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Reactivity: It allows the pedal to go back immediately as soon as you relax the foot.
- Technical specifications
| Feature |
Specification |
| Mark |
Birelart (original parts) |
| Compatibility |
22SR / 22SRR / CL pump |
| Material |
High resistance spring steel (tempered) |
| Function |
Piston reminder |
| State |
Must be perfectly cylindrical and without oxidation |
- Mounting tutorial: good positioning
Unlike the joints, the spring is simple to ride, but there are rules to prevent it from being laid.
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Inspection: Before reassemble, check that there are no traces of rust (oxidation). If the spring is stung by rust, change it. The rust is abrasive: it will create iron filings in your brake fluid, which will destroy your new joints in a few tours.
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Positioning: The spring is inserted into the bottom of the body of the pump and fits on the base of the piston. Make sure it is well centered and that it does not "scratch" against the internal walls of the aluminum cylinder during compression.
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Do not stretch: DO NEVER on a spring to give him back from force. A stretched spring is a weakened spring that will break prematurely. If it is soft, it is at the end of life: Replace it.
💡 Michel's trick
"Often, the pilots complain about a 'heavy' or slow brake pedal. They accuse the stirrups or purge. The trick: Most of the time, it is this spring that has lost its strength with time and heat. My Pro Council: When you redo your pump with the seal kit (cups), replace systematically This spring by a new one. It is a piece at a few euros that avoids having a pedal that seems 'gummy'. The difference of feeling at the foot is flagrant on a competition kart. "
❓ FAQ SEO (Frequently Asked Questions)
Q: Can we use a "home" substitution spring?
A: Absolutely not. Tare (the spring force) is calculated by Birelart to overcome the friction of the cups and ensure a quick return. A spring too soft will make the braking hazardous, a spring too hard will prevent the piston from doing all its run.
Q: Why did my spring become brown / black?
A: It is the sign of oxidation due to water in the brake fluid (the liquid has aged). If your spring is colored, it is that your liquid was too old and probably corroded the inside of your pump. Check the condition of the bore!
Q: Is the spring identical on all Birelart pump models?
A: No, there are variants of length and stiffness. Always use the reference corresponding to your model (22SR or 22SRR) to ensure compatibility.