BMW 640i Clutch fluid is contaminated Inspection at your home or office.

Common reasons for this to happen:

• Failing External Dust Boot: Clutches have a number of rubber parts that tend to fail. A ruptured or hardened clutch dust boot will allow dirt and moisture to gain access to the cylinder bore outlet and contaminate the fluid. The dust boot should be inspected on a regular basis to ensure that it is not failing.

• Failing Seal or Valve: The clutch cylinders have valve seals and if they fail it prevents the master cylinder from raising the proper pressure when the pedal is depressed. Once a seal fails it allows fluid to leak out and contaminates to enter the system.

• Clutch Fluid Leak: A leak in the clutch fluid system can lead to contaminated fluid. Water, dirt and even oil can end up in the system. A fluid leak will also make the vehicle hard to shift. The clutch pedal may go all the way down to the floor if the clutch fluid level is low.

• Clutch Fluid Needs to be Changed: Like all fluids, over time they pick up contaminants and become dirty. Clutch fluid needs to be replaced on a regular basis, usually at least once a year. If the system is losing clutch fluid on a regular basis the entire system should be inspected for leaks.

• Poorly Done Repair: A poorly done clutch repair or service can result in containments such as oil or water entering the system. A professional mechanic should do clutch work.