While cable-operated clutches are pretty common, so are hydraulic clutches. These systems offer a number of benefits, including smoother operation, no chance of the cable stretching or breaking, and more. However, they’re not without their issues. If you’ve noticed brake fluid leaking around the clutch pedal, there’s definitely a problem.
How this system works:
A hydraulic clutch works on the same principle as your brakes – it uses hydraulic pressure to engage your clutch, allowing you to change gears. When you press the clutch pedal, a metal rod and plunger moves into the clutch master cylinder. This pressurizes the fluid, and sends it to the slave cylinder, where it is then directed to operate the clutch, allowing you to change gears.
Depending on the make and model you drive, the master and slave cylinders could be located under the hood, mounted up against the firewall near your brake master cylinder. Alternatively, they could be mounted inside the cabin, behind the dash (which makes inspecting them rather difficult).
In all cars, the clutch master and slave cylinder share brake fluid with the braking system. Fluid is sent from the brake master cylinder through a small rubber hose. From the clutch master cylinder, the pressurized fluid moves to the slave cylinder through a metal tube.
Common reasons for this to happen:
- Leaking Hose from Brake Master Cylinder: One of the most common reasons to notice brake fluid leaking around your clutch pedal is a hole in the delivery hose that sends fluid from the brake master cylinder to the clutch master cylinder.
- Leaking Master Cylinder: The clutch master cylinder is subject to leaking at several points. One is the plastic fluid reservoir. However, the more likely problem is that the master cylinder seal has failed. Brake fluid is corrosive, and it will eventually degrade the seal, causing it to leak.
- Leaking Connection Pipe: While rare, it is possible that the leak you’re seeing is actually coming from the metal pipe that connects the master and slave cylinders. The fluid here is under pressure, and it’s possible for it to leak at either end (or through a hole corroded in the pipe in older vehicles).
- Failed Brake Master Cylinder Seal: It’s exceptionally rare for brake fluid to leak from the brake master cylinder to the clutch pedal, but it is technically possible. The most likely cause in this instance would be a failed master cylinder seal.
How important is this service?
If you’re noticing brake fluid leaking around your clutch pedal, you’ll need to take action quickly. A fluid leak reduces the amount of brake fluid in the system, which is required to operate both your clutch and your brakes. Low fluid can render both systems inoperable, and make it unsafe to drive your vehicle.