Brake fluid change topic

[hate2work]

Can you do the equivalent of several ATF drain and refills with your brake fluid and get mostly new brake fluid as a result?

Just watched a video of that very thing, the guy was driving about 100 miles between the removal of a few ounces and then adding the same amount of new BF. Does that really work? I mean, ATF fluid gets mixed right away, but how would new BF get mixed with the old stuff in the lines?

 

[dnewton3]

Swapping out the fluid in the reservoir is addressing only part of the issue.
To properly do a system exchange, one has to flush the old fluid down through the bleeders using new fluid.
Just sucking out fluid from the res is, well, silly.

 

[Lubener]

Can you do the equivalent of several ATF drain and refills with your brake fluid and get mostly new brake fluid as a result?

Just watched a video of that very thing, the guy was driving about 100 miles between the removal of a few ounces and then adding the same amount of new BF. Does that really work? I mean, ATF fluid gets mixed right away, but how would new BF get mixed with the old stuff in the lines?

You are not going to accomplish much by doing the turkey baster thing at the master cylinder. That new fluid will stay in or near the master cylinder. The only real way to do it is to crack open the bleeders at all four wheels and bleed the system.

 

[CharBaby]

Brake fluid DOES NOT recirculate. It just sits in the reservoir and pushes the fluid in the lines to the brakes, hydraulically.
You need to flush the brake fluid through your brake system. Definitely start with fresh fluid in your reservoir but then, bleed at each wheel.

 

[1000MPH]

Iirc in the old days you would break open the bleeders and get a bunch of rusty fluid. I can’t really imagine how many times you would have to do a res suck and fill to prevent that.

 

[JHZR2]

Pressure bleeder, speed bleeders, or gravity bleed.

Start at the furthest rear corner and bleed from there. You can see when the fluid goes from dark and damp to nearly clear.

There isn’t really another way or a better way…

 

[barryh]

If you just replaced the reservoir fluid with fresh fluid then some moisture would migrate into it from the rest of the system so there would be some benefit form an overall moisture reduction. What I'm thinking it wouldn't do is replenish the corrosion inhibitors in the rest of the system.

So a small temporary benefit but not a substitute for a full fluid change.

 

[shortyb]

As many have said, can't just do an exchange of the reservoir fluid and expect fresh fluid to migrate into the lines etc. You must go to each wheel's bleeder and pump out old fluid with new fluid. Motive pressure bleeder for a good, easy, and complete exchange of fluid. Takes longer to get the wheels off than bleed the entire system. A couple of my cars I can activate the ABS to get fluid out of the pump circuit as well.

 

[MasterSolenoid]

If you can do the work yourself, buy a quart of BF for <$10.00 and have the satisfaction of knowing you have ALL clean BF.
I do mine every two years.

If you need to pay someone to do this work, read your owner's manual (maybe doing every three years).

 

[eljefino]

There is an insanely small orifice between the reservoir and the working portion of the master cylinder. It's intended to only allow a slow drip of fluid when your foot is completely off the pedal, to make up space created by the wearing of disc pads. Once you touch the pedal this orifice is covered, otherwise the fluid would squirt up into it. So check out that tiny bit of play, that's it.

Sometimes reservoirs are just a friction fit that pop on the M/C. You theroetically have brakes if you pop it off. (Don't.)

Hoping the qualities of fresh fluid will help the stuff down in the wheel cylinders via diffusion is optimistic. However, if you do bleed your brakes, start by sucking the old stuff out of the MC so it doesn't get pushed down.

 

[Ronsant]

How does the addition of ABS change the equation?
Do you need a tool to “cycle” the ABS pump? Is there anyway to do a fluid change without cycling the ABS?
Thanks,

 

[eljefino]

Generally people find a dirt road and lock 'em up to get the thing to cycle. The most retentive among us then do another bleed. IMO the trouble spots are at the calipers and wheel cylinders, low dead-end spots. Get the moisture and copper out of the fluid at the corners and you're ahead of most people on the road.

 

[JohnnyG]

Fake news.
(the video, only good for clicks)

 

[D1sc]

This is something I’ve been doing since 08 every time I change engine oil I empty the brake and clutch fluid (Audi is combined) with a turkey baster since a battery filler is harder to clean and refill. My vette builder told me to do this because the triple disc clutch works hard and autocross had me fading brakes consistently.

 

[Volvohead]

As many have said, can't just do an exchange of the reservoir fluid and expect fresh fluid to migrate into the lines etc. You must go to each wheel's bleeder and pump out old fluid with new fluid. Motive pressure bleeder for a good, easy, and complete exchange of fluid. Takes longer to get the wheels off than bleed the entire system. A couple of my cars I can activate the ABS to get fluid out of the pump circuit as well.

Ancient Chinese Secret for using a Motive or other portable pressure bleeder … and never having it touch fluid: Top off the MC reservoir, and use the Motive for air pressure only. As long as you don’t run the MC reservoir dry, you can rinse and repeat the process for as much fluid as you want to pass through the system. Infinitely cleaner, and there is nothing left over in the pressure tank to deal with later.

 

[NibbanaBanana]

No. Tried that and it didn't work at all. The fluid doesn't migrate around at all. Chris Fix has an excellent YouTube video on how to easily change your brake fluid. I change it every 30K miles now and haven't had a problem with any car brakes since I've been doing it.

 

[Lubener]

How does the addition of ABS change the equation?
Do you need a tool to “cycle” the ABS pump? Is there anyway to do a fluid change without cycling the ABS?
Thanks,

It will only be an issue if the system is allowed to go empty.

 

[Lubener]

This is something I’ve been doing since 08 every time I change engine oil I empty the brake and clutch fluid (Audi is combined) with a turkey baster since a battery filler is harder to clean and refill. My vette builder told me to do this because the triple disc clutch works hard and autocross had me fading brakes consistently.View attachment 204414

Turkey basting is a waste of time and a good opportunity for moisture to get in. Fading brakes are due to overheated brakes.

 

[Pew]

We'd use either 1 big bottle of brake fluid or 3 smaller bottles and call it a day for a flush before the track. In-between track days we'd do a bleed.

 

[ordinarybloke]

The turkey-baster and nothing else, is a dealer-dodge. Better than nothing, but fluid won't mix old with new. Go to each corner.

Except on say a clutch, where there's one MC, one pipe, and one slave. Even then, better than nothing, yet still it's not wisest.