How to add brake fluid to the clutch master cylinder

How to top up the brake fluid in your car’s clutch master cylinder

Topping up the clutch master cylinder reservoir is something that any car owner can tackle with confidence. This is a simple task which will make a big difference to maintaining your car, and extending the life of your clutch.

As your clutch wears, the brake fluid automatically adjusts the position of the clutch pressure plate. This action ensures that the car’s clutch is always at its optimum adjustment. This adjustment causes the level of fluid in the master cylinder to slowly, but gradually drop.

If the level of fluid in the clutch master cylinder is allowed to drop below its minimum level, then your clutch will be constantly engaged. Not enough to be noticeable, at first, but eventually it will burn your clutch out.

The clutch is an expensive item to replace, and the old saying is quite true, an ounce of prevention is worth a pound of cure. If a simple thing such as checking the brake fluid level in your master cylinder can save additional wear and tear on your clutch, then it’s worth doing.


Step 1


The very first thing to do is buy a container of brake fluid. You don’t need a large bottle for this type of task. Brake fluid takes in moisture from the air and deteriorates over time once the bottle is opened. It’s best to check the car’s handbook for the proper fluid to buy.

Step 2

Keeping the work area clean

Use a rag to wipe down any dirt on the clutch master cylinder. Brake fluid and paint don’t get on very well, so place a rag around and under the master cylinder reservoir. This will catch any spills or dribbles.

Step 3

Remove the cylinder cap

Once you have protected the area with a rag, unscrew the cap from the cylinder. Have another rag handy to lay the cap onto. This will prevent any fluid on the cap getting on the car’s paintwork, and stop dirt getting into the brake fluid. Contaminated brake fluid soon starts to break down, and becomes less efficient.

Step 4

Topping up the clutch master cylinder

On the outside of the clutch master cylinder reservoir, you will see two lines. These are the minimum and maximum fill lines. Carefully remove the top of the brake fluid bottle and pour the fluid into the reservoir until the maximum line is reached. Sometimes the cylinder can be in a bit of an awkward area to reach without spilling the brake fluid. If this is the case, use a little funnel to help fill the reservoir, but first ensure it is perfectly clean and dry.

Step 5

Replace the cap and tidy up

Once you have topped up the reservoir, replace the cap and give the cylinder a little wipe down. Remove the rags from around the clutch master cylinder, and the job is done. Just remember to wash your hand when finished.

You will Need
• Small bottle of brake fluid.
• A couple of clean, dry rags.
• A pair of latex gloves
• Small funnel (optional)

Tips & Warnings
• Always use fresh brake fluid.
• Remember to keep the area clean.
• Don’t spill brake fluid onto the paintwork.
• Wash your hands afterwards, brake fliud is poisonous


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