You may want to allow the vehicle to cool for an hour or two to prevent burning yourself when checking the fluid levels. Parking at an angle may make it appear that you have more or less brake fluid than you actually do.
In some vehicles, the safety release is located in the grill rather than under the hood. If you are unable to locate the release, check in your vehicle’s owner’s manual for guidance.
If you are having difficulty locating the clutch master cylinder, refer to your vehicle’s service manual for assistance. The clutch master cylinder is usually on the driver’s side of the vehicle.
If the brake fluid is well below the minimum line, there may be a leak somewhere in the system. Leaks not only allow brake fluid to escape, but allow pockets of air to enter which can cause further issue when operating your clutch.
Most vehicle’s require SAE J1703, US FMVSS or 116 DOT 3 brake fluid in the clutch master cylinder. If you do not have a copy of the owner’s manual for your vehicle, look for the information you need on the automaker’s website.
You can tear the seal off of the brake fluid container completely, but it will make it harder to direct your pour without spilling any. Be careful not to overfill the reservoir as it may cause the clutch to not function properly.
If anything falls into the brake fluid in the open master cylinder, try to scoop the debris out or dab at it with a dry cloth. Keep the lid on the clutch master cylinder reservoir at all times when not filling it.
If the lid is damaged, place it back on the reservoir and do not drive the vehicle until you purchase a replacement. Replacement lids can be found at your local auto parts store.
Pockets of air can cause the clutch to not engage or disengage properly. Air in the clutch lines can be a symptom of a leak, so be sure to check carefully for one.
Once you’ve cleaned the master cylinder, start the vehicle and have a friend press the clutch a few times. Look for signs of bubbles or fluid leaking from the master cylinder. Check the reservoir and master cylinder again after a few days to ensure there are no leaks.
If you locate a leak, you should have it repaired immediately. After sealing a leak, you will need to bleed the clutch system.
A failed clutch will not allow you to put the vehicle in gear at all. Slight grinding between gears may be due to clutch pressure issues, but may also be caused by failing synchros within the transmission.