If and when changing\flushing the DOT 4 fluid and the old fluid looks clear, how can you tell when the old fluid has been flushed?

When checking my front brake fluid level, I noticed moisture behind the rubber cap, but none in the DOT 4 fluid itself.

 

You can use a moisture meter for brake fluid, if it's clear and dry it's good.

 

Get you one of these:

 

I have that meter. But how to tell when the lines are flushed? My reserve showed 3-4%. Now it shows 1%. By how to tell when the lines are flushed too?

 

Empty the bottle the drained flush fluid goes into, then flush a little more into the bottle so the fluid is clear then measure it. Once you are at or below 1% you are good.

 

catch and test a small sample of the just bled off fluid.

 

To properly bleed one with ABS you need the software to cycle the abs while bleeding. I use Daytona Twin Tec. You can do a manual regular bleed, but the equipment cycles the abs while bleeding to ensure complete flush and new fluid in the ABS unit.

 

Yes, I do have an ABS flush tool. Great suggestion for bleeding into a separate container.