This is usually located in the engine bay on the other side
of the dividing bulkhead to the brake pedal
Examine for leaks and/or corroded pipes leading to the unit.
Rubber pipes should
not be split or show damage or wear.
The fluid in the reservoir should be in between the min and max levels
as indicated on the side of the reservoir.
The top shop be in place to prevent fluid spillage.
Check around the cylinder for any signs of leakage.