Bakit nagbabawas ang level ng brake fluid?

Описание: The automobile brake system is a hydraulic system that uses brake fluid to transfer pressure from the brake pedal to the brake calipers or wheel cylinders, which then press the brake pads or shoes against the rotors or drums to slow or stop the vehicle.

Main components include:

Brake pedal – The driver applies force.

Brake master cylinder – Converts pedal pressure into hydraulic pressure.

Brake lines and hoses – Carry the brake fluid to each wheel.

Calipers (disc brakes) or wheel cylinders (drum brakes) – Use hydraulic pressure to push pads or shoes.

Brake pads and rotors (or shoes and drums) – Create friction to slow the wheels.

Brake fluid reservoir – Stores brake fluid for the system.

Why Brake Fluid Level Reduces Even Without Visible Leaks

Even when there’s no obvious leak, the brake fluid can gradually decrease over time due to normal system operation or hidden causes. Common reasons include:

Brake pad wear

As brake pads wear thinner, the caliper pistons move further out to compensate.

This extra piston travel retains more fluid in the calipers, causing the level in the reservoir to drop slowly.

Fluid absorption and evaporation

Brake fluid is hygroscopic, meaning it absorbs moisture from the air.

Over time, moisture contamination can slightly reduce the effective fluid volume or cause minor evaporation through the cap vent.

Tiny internal leaks

The master cylinder seals or caliper piston seals may leak internally — fluid moves past the seals but doesn’t drip outside.

These leaks don’t show visible fluid loss but can still lower the reservoir level gradually.

Temperature-related expansion and contraction

Heat from braking can cause the fluid to expand and contract. Repeated cycles can lead to small fluid volume changes and apparent level drops.

Brake bleeding or topping error

If air was not fully removed during past brake bleeding or the fluid wasn’t topped properly, the level may appear to “drop” as the system stabilizes.

What to Do

Check brake pad thickness. If pads are worn, fluid drop is normal — it will return to normal when new pads are installed.

Inspect for hidden leaks at the master cylinder (especially behind the brake booster) and all connections.

Replace brake fluid every 2 years or as recommended — old fluid absorbs moisture and reduces braking efficiency.

Monitor fluid level. Rapid drops are not normal and indicate a serious issue.