Originally Posted by jayok
Oh yeah - I was looking at the sealey VS820. Seriously though I normally suck out the old brake fluid from the reservoir first then then fill with fresh fluid and clear the lines. It means less of the old fluid to bleed. That's what I use the syringes for.
Ah, I see, so you're still getting rid of the old, nasty stuff from the lines. Very important.
Had an old Merc once and the brake fluid in the lines was 20+ years old. Came to roundabout, pressed brakes, nothing.
Had to pump the brakes several times to get them working.
Retained moisture in the fluid can boil, leaving you with steam, effectively gas in the lines and gas compresses. Bad idea in a hydraulic system.
It always amaze me how every garage always tells me about brake fluid, coolant, gearbox oil, diff oil, power steering fluid "Nah, that stuff never needs changing, it will last forever and an unlimited amount of miles". Because they can't be arsed changing it and still charge the same for a service.