As the brake pads wear down, the caliper pistons STAY OUT, and so all the time you drive the car and use the brakes there is a very gradual wearing of the pads, resulting in a slight reduction of the fluid level in the master cylinder reservoir.
If the pads wear quickly (cheap ones, or soft linings, or lots of heavy braking) you might notice this and think you have a leak.
ah .... so he did. t was hiding off the right side of my screen.
LandyZone is wider than either of my screens (I run two side-by-side)
Bloody nuisance actually.
If there's no sign of a leak, I still think his "loss" is only pad creep.
That is a very good point, and I have seen that myself.
There is a seal around the pushrod between the servo and the master cylinder. If he slackens off the two nuts holding the master cylinder to the servo he may be able to wiggle the master cylinder away from the servo enough to find out if there's any sign of brake fluid there.
There should be NO BRAKE FLUID in the space between the servo and the master cylinder. If there is, the master cylinder needs new seals.