Skip the auto shop - Our mechanics make house calls

What Can Cause Brake Fluid to Leak From the Brake System?

brake fluid leak

The braking system in a vehicle is designed to circulate brake fluid, using it create the pressure against the wheels when slowing or stopping is desired. It is a closed system, which means that the fluid doesn’t evaporate over time and require periodic topping off when it is operating optimally. If you have a brake fluid leak, it is anything but natural and is the result of another problem in your braking system. The only possible exception to this rule is if you’ve recently had parts of your brake system serviced and the brake fluid reservoir is low; this just means that the fluid has naturally settled throughout the system and required a little more to be completely full.

Since a brake leak can lead to brake failure, this is not an issue to take lightly and requires your immediate attention for your own well-being and the safety of others. Here are some of the most frequent reasons why a vehicle may leak brake fluid:

  • Damaged brake lines or fitting: This is a very serious issue that, although inexpensive to fix, can endanger lives if not tended to quickly. You will know if there is a hole in one of the lines or a failed fitting if there is little to no resistance when you press the brake pedal, even after pumping it several times to try and build up pressure.

  • Loose bleeder valves: Also known as bleeder bolts, these parts are situated on the brake calipers and serve to remove excess fluid when servicing other parts of the brake system. If you have recently had a brake fluid flush or other work, the mechanic may not have tightened one of the valves fully.

  • Faulty master cylinder: When brake fluid accumulates on the ground underneath the rear of the engine, the master cylinder is a likely culprit, although it could also indicate an issue with the slave cylinder. With other brake leak issues, the fluid tends to pool near the wheels.

  • Bad wheel cylinder: If you see brake fluid on one of your tire’s walls, then you probably have a bad wheel cylinder if you have drum-style brakes. Another symptom of a brake leak from a wheel cylinder is your car pulling to one side as you drive due to uneven fluid pressure.

If you have seen evidence of your car or truck leaking brake fluid or have checked the levels and found them low, seek help immediately. Our mechanics can come to you for a complete inspection to diagnose the cause of your brake fluid leak.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance Related Trouble Codes: P2158: Vehicle Speed Sensor B P2160: Vehicle Speed Sensor B Circuit Low P2161:...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed Related Trouble Codes: P2441: EVAP Vent Valve Stuck Open EVAP trouble...
P0291OBD-II Trouble Code: Cylinder 11 Injector Circuit Low
P0291 code definition When your vehicle’s PCM registers the P0291 code, it means that a voltage reading came from the fuel injector circuit – for cylinder number 11’s fuel injector –...


Related questions

Q: Brakes locked up

When the rotors get this hot, this is usually an indication that the brake pads are dragging on the rotors. This can happen when the brake calipers are misaligned on the rotors. This problem is often compounded when, as a...

Q: no reverse

The first thing to check is the transmission's fluid level. If the transmission works in the other ranges, like park and drive, there is a very good chance the transmission will need to be rebuilt or replaced. If you would...

Q: Locked brakes - 2004 Cadillac CTS

Hi there. From the description you have provided, your vehicle's left front and right rear caliper locking would have been a combination/proportioning valve before ABS (anti-lock brake system). The EBCM (electronic brake control module) controls the valves in the hydraulic...