I've been wondering something about bleeding brakes before track events.
It's common knowledge it needs to be done - brake fluid absorbs water from the air, and it's boiling point lowers, and when the brakes get hot, if it boils, your brakes get squishy. And so you need to bleed them regularly before track events.
My question is, how does the water get into the sealed brake system? It's not open to the air, right? At least down by the calipers - the reservoir obviously is not water tight, but the whole rest of the system is clearly liquid tight. How does the water get in?
And when you bleed it, you need to replace the fluid in the caliper, but do you need to replace the rest of it? If you do a normal "forward" bleed, from the reservoir down to the calipers, you need to completely flush the old fluid out, right? I use a turkey baster and empty the reservoir, fill it with fresh fluid, and then bleed it a goodly amount using speed bleeders. Is that what you guys do? I know there are reverse bleeder systems that push it up from the caliper, but those seem to need a large amount of fluid in them, and you'd have to replace all that every time, because it would absorb water in between track events too, right?
It's common knowledge it needs to be done - brake fluid absorbs water from the air, and it's boiling point lowers, and when the brakes get hot, if it boils, your brakes get squishy. And so you need to bleed them regularly before track events.
My question is, how does the water get into the sealed brake system? It's not open to the air, right? At least down by the calipers - the reservoir obviously is not water tight, but the whole rest of the system is clearly liquid tight. How does the water get in?
And when you bleed it, you need to replace the fluid in the caliper, but do you need to replace the rest of it? If you do a normal "forward" bleed, from the reservoir down to the calipers, you need to completely flush the old fluid out, right? I use a turkey baster and empty the reservoir, fill it with fresh fluid, and then bleed it a goodly amount using speed bleeders. Is that what you guys do? I know there are reverse bleeder systems that push it up from the caliper, but those seem to need a large amount of fluid in them, and you'd have to replace all that every time, because it would absorb water in between track events too, right?
