I'm changing the factory porsche brake fluid for Castrol SRF. Obviously my fluid looks brand new. What's the best way to tell when you have the old fluid flushed out and the new fluid all the way to the calipers? Would you draw the old fluid out of the master cylinder with a syringe before adding the SRF? At $75 per liter I don't want to waste it. B-

 

Most people will tell you a power bleeder is your best solution for home bleeding. SRF if I recall is clear (yellowish) as is your OEM brake fluid. Many people use Motul Blue and Yellow and just rotate: When it goes blue, you're flushed, when it goes greenish/ clear: you're flushed.

So no real solutions in your situation other than maybe getting some Motul blue and saving your SRF for the next bleed: FYI, I stopped using Castrol SRF long ago simply because of price. If you look at boiling temp's of Motul Blue/ Yellow vs SRF, there is not enough difference (in my mind) to justify the cost difference.

As for your question to syringe-draw fluid from the master cylinder; I'd definitely not suggest it because what replaces fluid is air. I'm sure it can be done, especially if you just watch for bubbles as you're bleeding the lines, but I think trouble is more likely.

For what it's worth, when I bleed mine (using color change to indicate when I'm done) I typically put in a quart of new (into the power bleeder) start with right rear and remove ~ 8 oz, then 4 oz (left rear), 2 oz (rt front), 1 oz (lt front). This would be a very rough estimate if you don't have color change to tell you otherwise.

I think the MOST MOST MOST important thing when changing brake fluid is not new vs. old fluid or debris. It's air. As long long as you are not seeing bubbles towards then end of your bleeding (per wheel) you're probably fine.

 

Thanks KK Moto for the response. I was thinking using the syringe to pull the majority of the fluid out of the MC but leave enough in the bottom so no air enters the system. I do use a power bleeder.