What to know about the Clutch Master Cylinder & Slave
A clutch master cylinder contains a reservoir that stores the brake fluid. It is linked to the clutch slave cylinder through hoses. When you push the clutch pedal, brake fluid flows from the clutch master cylinder to the slave cylinder, applying the pressure necessary to move (engage) the clutch.
It has internal and external seals that can fail. If the external seals wear out, the clutch master cylinder will leak brake fluid, reducing the amount of fluid in the car and causing the clutch to malfunction. You may also find leaked brake fluid down by the clutch pedal (inside the car). If the internal seals wear out, the clutch fluid will continue to circulate inside instead of being directed to the slave cylinder. In that case, the clutch pedal will go all the way to the floor when you apply the clutch.
Facts to Note:
Every time the clutch master cylinder is changed, it is recommended to change the slave cylinder as well. When the master cylinder goes bad, it is extremely common for the slave cylinder to follow suit.
Note that some clutch slave cylinders are fitted inside the transmission. To change this type of slave cylinder the transmission has to be removed.
How to Fix:
Check clutch master cylinder and slave cylinder.
Check the condition of brake fluid.
Examine the operation of clutch pedal.
Remove and change clutch master cylinder and slave cylinder.
Bleed all air from the master cylinder.
Test drive the vehicle.
During an oil change, the mechanic should check the amount of brake fluid. If you feel a change in the way the clutch pedal feels (softer pedal) when stepping on it, you should have a mechanic examine the clutch master cylinder and hose.
Clutch fluid should be changed every 24,000 miles.
Common symptoms indicating you may need to change the Clutch Master Cylinder & Slave Cylinder:
Clutch pedal goes all the way to the floor.
Brake fluid leaking around the clutch pedal.
Not able to change gears.
Importantof this service:
The clutch master cylinder stores brake fluid. When the clutch pedal is depressed, the fluid is transferred from the clutch master cylinder to the slave cylinder, which generates the pressure required to engage the clutch. If the clutch master cylinder is leaking, it won’t hold the correct amount of brake fluid, and there will not be enough pressure from the fluid to engage the clutch.