Valvefloat991

There's one part of flushing the brake fluid that I find difficult. If one performs this flush every two--or even three--years, the fluid coming out of the brakes is as clean as the fluid you're using to replace it. So how do you know when you've flushed enough fluid out of each caliper?

In the Nineties, this was less of a problem, as brake fluid was available in different colors. ATE, for example, manufactured decent fluid in both amber and blue colors. This made it determine when you ahd completely flushed the old fluid. And you just alternated colros with every brake flush. Then, in its infinite wisdom, the Depart of Transporation outlawed this practice, and assigned colors to several kinds of automotive fluids, lest some nimrod mistake brake fluid,for hydraulic fluid--or Coca Cola.

How do you guys solve this problem?

rubycaymanr

I measure the evacuated fluid. 700 ML for Passenger Rear, 250 ML for Drivers side rear and 150 ML for the 2 front wheels. In addition I do 50 ML for each of the inner bleeder screws. Its probably more than needed but I play it safe... . .Hope that helps

DC991

999.1 brake bleed procedure:
https://rennlist.com/forums/991/9568...procedure.html

CSK 911 C4S

Time and the amount. It really isn't rocket science.

The rear passenger is the longest to flush so I usually fill up one of the catch bottles to capture all of what's in the lines and what ever was left in the bottle at the start. The other's I usually just fill up to about 1/2 the catch bottle.

One liter of brake fluid is enough to do the entire system unless you changed out a brake component and need some longer flushes to extract air.

asellus

as an aside, I thought the ATE blue colouring was found to be carcinogenic or super bad for the environment or some such, and that was why it stopped being produced.
never mind I am an idiot and spent eight seconds googling it, turns out it is indeed a "protect americans from their own stupidity" law.

4 Point 0

Mine gets changed about 4 times per year. Every pad change, and every rotor change. I track the car. But even my cars I don't track, I believe they should be done every year.

Brakes seem important to me. I run Castrol SRF in everything, except the Macan Turbo (Mainly wife's car). Very small price to pay to never experience brake fade.

I hear people say, they would never buy a car that has been tracked. Quite frankly, I'd never buy one that wasn't. Guys who don't track, have everything perished and most go years with little to no maintenance. Original tires, oil, brake pads, rotors and brake fluid after 4 years sounds horrific to me. It sounds like an accident waiting to happen.

Tracked cars always have fresh fluids, fresh tires, fresh pads, fresh rotors. Consumables should be consumed, and refreshed. IMO.

justabout

Due to mixing, you don’t get all the old fluid so I flush it once a year. I use 2 liters, probably overkill.

shyamvenky

I've read that DOT 4 and DOT 5.1 brake fluids can be mixed because they're made from same/similar base chemicals.
Is there a color difference between those two?

Valvefloat991

I believe that all brake fluid is amber in color--by Federal regulation!

Thanks for all of the advice. Some of the specified amounts to flush make sense, but it all feels a bit like guesswork. If in doubt, keep flushing, seems to be the word.

By the way, good brake fluid prevents the fluid form boiling, which is very different than brake fade. Fade can happen even with perfectly liquid fluid, if the pads and rotors overheat.

Wujohn

I've followed the link @DC991 referenced for 5 years and have never had an issue. I do change fluid much more often than recommended due to tracking the car but have never had an issue (Castrol SRF). Only difference is I use the dry method, which makes cleanup easier.

As long as you've not left the fluid for years and years, those directions work great.

WJGreer

This thread reminds me of a time I had a Ford Explorer at the shop for an oil change. I'd had the differential fluid changed a month earlier somewhere else. The guy came into the office from the garage carrying his little tray of fluid samples to show me how dirty "my" differential fluid was.

I told him that I'd make him a bet. We could go out to the truck and take a new sample of differential fluid while I was watching. If it was as dirty as the sample he showed me, I'd do the fluid flush plus 20 bucks for his trouble. If the fluid was clean, I wanted my oil change at half price that day.

Guy said "I'm sorry man, they make me do this for every customer, this isn't your fluid."

Never been back.

ZnZBar 986S

My buddy and I were just discussing the same topic as I bled the practically new fluid (flushed by the dealer before I bought the car in October) and replaced with SRF. Super Blue made life so much easier. Use quality fluid, flush it annually and even if you still have a few drops of the old stuff, you'll be way ahead of the guy who has a 10yo 991.1 with the original fluid from the assembly line. You know they're out there!

Jack F

Good info here.