I thought my brake fluid level was going down so marked it with a pencil. Tonight upon checking it, a month after marking & 2000 miles later it has gone down about 1.5mm from where marked. Not much I know, but is this a problem? I've remarked it to see if it goes down again. Should the level remain constant. I presume it doesn't matter if I'm checking level when engine is hot or cold?

Cheers

nothing really to do with engine temp but brake temps willo affect it slightly.it will go down with pad wear though

So it could be OK, just down to pad wear?

Did 100 miles today and it didn't move from the pencil mark. If I'm losing a mm every 1k is that acceptable?

Obviously if I hadn't have marked it I wouldn't know!

Pad wear is a big factor

On mine there was an eigth of an inch left on the pads. The new pads were about half an inch-ish (if not more)

over four pads on two wheels- this makes a difference to piston positions and possibly fluid levels