Help - Bleeding brake fluid - How to know when new fluid is in the cal

[Mz3bo]

Hi Folks,

Sorry for this newbie question.

When I put the power bleeder cap on and pump to 20psi, how do I know where my new brake fluid is at ? I mean, once you open the bleeder valve on the first caliper, when do you know that the new brake fluid has "arrived", and how do you make sure the old/new fluid is not mixing togother in the brake system ??

Thanks

[Izzy]

One easy way is to change colors every change, from ATE Superblue to Gold. That way is postive that the flow is there.

Otherwise, if you are changing from gold to gold, you will see the dirtier or darker fluid come out first, then the cleaner and clearer new one later.

[KevinC]

If you are not using a different color fluid, it will be very hard to see when all the old fluid is out. The fluid in the calipers which has gotten very hot may be a darker color but, if you are doing a full flush, you want to exchange all the fluid.

I make it simple for myself. I know that a one liter can is more than enough to do a full flush of the fluid, so I just flush the fluid into a similarly sized clear bottle and remove about a quarter of a liter from each caliper. I take a bit more from the rear calipers which are flushed first and have longer lines leading to them. But, as I say, a liter is more than enough so you don't need to be very precise.

[djantlive]

Old fluid typically has darker color as said. Sometimes, you'll see some bubble in the line as well. Typically, there isn't that much to be flushed out. A litre should have 1/4 left over so if you use a full litre, you're definitely flushing out all the fluid. As KevenC said, the rear ones need to bleed out more.