How to Fix Air Leakage from the Brake Master Cylinder Vent?
2 Answers
Methods to repair air leakage from the brake master cylinder vent: 1. Remove the master cylinder and clean it thoroughly, then inspect the air shut-off valve for any cracks. If cracks are found, apply some grease at the cracked area and reassemble it properly; 2. Install air filters on the two branch pipes leading to the master cylinder to solve frequent air leakage issues, and purchase a repair kit for the same model of the master cylinder; 3. If the leather cup of the master cylinder is leaking, it needs to be replaced entirely. When pressing the brake pedal, if you notice the braking feel is significantly softer and the stability of continuous braking decreases, it might indicate poor sealing of the master or slave cylinder pistons, or a crack somewhere in the brake lines causing oil leakage.
I've dealt with the issue of brake master cylinder vent port leakage several times. This is usually caused by aging seals or a damaged vent valve. When the seal fails, brake fluid can leak out, allowing moisture from the air to enter, which leads to a spongy brake pedal or even brake failure. You'll need to open the engine hood first, locate the vent port, check if the reservoir fluid level is low, then wipe the surrounding area clean with a cloth to look for signs of oil leakage. If it's a seal problem, you can buy a new set of seals to replace them yourself for about a few dozen yuan. Remember to bleed the air and add new brake fluid afterward. However, if you can't handle it, it's advisable to go to a repair shop because air leakage might affect the entire brake pump, posing significant safety risks over time. Always check the seal condition during every maintenance service—don't wait until something goes wrong to fix it.
