Brake Fluid question

[Repack]

My dad bled the brakes on his car a few weeks ago with racing fluid and has some left over that I am thinking about putting in the disc brakes of my downhill mountain bike. What I am wondering is how long it takes for an opened bottle of fluid to draw in water. I think that I am just going to try it since bleeding them is simple but wanted to know if there was any sort of general rule of thumb or whatever.

 

Thanks

[mws]

The simple answer is.... it depends!

 

1) How well sealed was the cap when it was put back on the shelf?

 

2) What was the humidity on the day it was originally opened and reclosed?

 

3) What is the average humidity in your area?

 

4) How hygroscopic is the brake fluid?

 

If the answers are:

1) well 2) low (under 20%) 3) Low (usually under 40%) and 4) Low (like Castrol LMA)

Then it will be OK for several months

 

If the answers are:

1) cap? What cap? 2) Raining 3) Let's see, average humidity in Pensacola is, ummm.... 4) Traditional Dot 3, 3.1, or 4

Then maybe a day....