Where exactly are you (the cap, the lever, or the hose)? Does the brake lever feel firm or soft when you squeeze it?
Remove the reservoir cap and inspect the rubber diaphragm. Look for tears, swelling, or flat spots. If the gasket looks distorted, it will never provide a vacuum-tight seal. Replacement gaskets are inexpensive insurance against a ruined ride. ski bri of leaks free
When reinstalling the cap, do not "crank" the screws down. Tighten them evenly in a cross-pattern until they are snug. Over-tightening is the #1 cause of cracked reservoir bodies. Advanced Troubleshooting: The "Pro-Fix" Where exactly are you (the cap, the lever, or the hose)
The rubber seal under the reservoir cap can perish or become pinched. Look for tears, swelling, or flat spots
Always use the specific DOT fluid recommended in your owner’s manual (usually DOT 4). Mixing fluid types or using old fluid from an unsealed bottle can cause seals to swell or shrink, leading to immediate leaks.
To ensure your system remains bone-dry throughout the season, follow these maintenance essentials: