Depressing caliper pistons

[emmett442]

Sure I have. Going one step further, it's in contact with air before you even pour it out of the bottle!

Originally Posted By: SHOZ
It's not a completely sealed system as the Master Cylinder has to be vented or it will not work


Originally Posted By: Claud
it absorbs water. Normally atmospheric humudity via the master cylinder vent.


But these ^^^ 2 posts previous to mine made it sound like fluid in the master cyl is directly vented to atmosphere, which is incorrect. Could be confusing to other readers. The system IS SEALED with the cap on, and vented via a bellows.

 

[Claud]

Originally Posted By: emmett442
Sure I have. Going one step further, it's in contact with air before you even pour it out of the bottle!

Originally Posted By: SHOZ
It's not a completely sealed system as the Master Cylinder has to be vented or it will not work


Originally Posted By: Claud
it absorbs water. Normally atmospheric humudity via the master cylinder vent.


But these ^^^ 2 posts previous to mine made it sound like fluid in the master cyl is directly vented to atmosphere, which is incorrect. Could be confusing to other readers. The system IS SEALED with the cap on, and vented via a bellows.


On American cars, yes. But not on most cars sold in the UK. It seems to make little difference in the life of the fluid in my experience. My wife & I run European cars as daily drivers, old American cars for fun.

Claud.

 

[SHOZ]

So how does the fluid get contaminated with water over time?

 

[nthach]

I've been getting into the practice of cracking the bleeders open, retracting the caliper piston in followed by a partial flush that takes care of the bleeding. It only takes a few more minutes and 12oz of brake fluid.

At least the new stuff will replenish the corrosion inhibitors in the current fill, as most cars do have diagonally split brakes. Unless it's a Prius(or other Toyota hybrid) or a Mercedes with Sensotronic braking, in that case there's a F/R split and the front brakes will be put into emergency duty if there's a electrohydraulic failure.