Can't tell if all old brake fluid is out - The old fluid is as clear as the new

[Palut]

My buddy came over with his Civic wanting to change his brake fluid. I think the fluid was 4-5 years old. We started bleeding the brakes, but ran into the issue that the old fluid coming out was just as clear as the new fluid going in.

All advice I can find online says that you'll know the old fluid is all out when the fluid coming out of the brakes turns clear. How can you tell that though if the old fluid was already clear to begin with? Are there any other tricks?

 

[slacktide_bitog]

How old is the car? Has it had any other work done to it recently?

Just flush out a good amount, typically a quart for a car, or about 8 oz/250mL per wheel/caliper.

Speed bleeders are awesome. I usually just do 6-7 pumps per wheel, which ends up being a quart for the whole car

 

[mrsilv04]

If no one could tell the difference in the old fluid and the new fluid.... then how badly did the old fluid really need to be changed? Seems like a waste of time and effort to me.

There used to be a company that sold tinted brake fluid... until our helpful federal government put a stop to that total insanity.

 

[Tomioka]

Get some brake fluid test strips to get a definite condition on the brake fluid.

 

[The Critic]

For a car of that size, exchanging at least 24 oz should be more than enough to flush out the old fluid.

 

[ChristianReske]

Change it every 2 or 3 years for safety reasons. Dont take a risk.
The coluor says nothing. Atfer 2 years, you can hardly tell a difference between old or new brake fluid by the colour. The old fluid is just a little bit more cloudy, opaque. Thats it.

It´s the hydraulic clutch system where the brake fluid turns black soon. But nobody knows why...

There are electric brake fluid testers available, cheap. Buy one.

 

[CharBaby]

I always start with fresh fluid in the master cylinder. Then start bleeding. Lot of folks like to change brands/iridescent color each time they bleed so they can see the difference from one to the other. But, I can usually tell as my fluid in the system is usually darker than the new fluid.

 

[Snagglefoot]

There are plenty of brake fluids that are light yellow. As far as changing out brake fluid, if your old stuff is clear, it is Bitog anal retention at work if you change it.

 

[demarpaint]

How old is the car? Has it had any other work done to it recently?

Just flush out a good amount, typically a quart for a car, or about 8 oz/250mL per wheel/caliper.

Speed bleeders are awesome. I usually just do 6-7 pumps per wheel, which ends up being a quart for the whole car

I agree, a quart per car works out quite well. Sometimes we over think things.

 

[supton]

Most cars go 10-20 years without changing, Changing “most” is vastly better. I would not over think it.

 

[Falcon_LS]

Out of interest, what brand/type fluid did you use?

I stick with DOT 5.1 (or "DOT 4 Plus"), and change it out every 6 months. At that point, the fluid in the reservoir looks like olive oil, and it's very easy to tell when you've thoroughly flushed out one side.

 

[Jetronic]

My buddy came over with his Civic wanting to change his brake fluid. I think the fluid was 4-5 years old. We started bleeding the brakes, but ran into the issue that the old fluid coming out was just as clear as the new fluid going in.

All advice I can find online says that you'll know the old fluid is all out when the fluid coming out of the brakes turns clear. How can you tell that though if the old fluid was already clear to begin with? Are there any other tricks?

I use vacuum to pull the fluid through, this causes bubbling in the fluid. No doubt the bubbles come from sucking air through the bleeder but the bubble size is night and day different between old and new fluid.

When I can't see the fluid or bubbles, I go with volume.

 

[atikovi]

Most cars go 10-20 years without changing,

From one neglectful extreme to

I stick with DOT 5.1 (or "DOT 4 Plus"), and change it out every 6 months.

a pathologically OCD extreme. Only on BITOG.

 

[supton]

From one neglectful extreme to

a pathologically OCD extreme. Only on BITOG.

Care to explain how I stated that one should go 10 years and not change brake fluid?

 

[BMWTurboDzl]

Change it every 2 or 3 years for safety reasons. Dont take a risk.
The coluor says nothing. Atfer 2 years, you can hardly tell a difference between old or new brake fluid by the colour. The old fluid is just a little bit more cloudy, opaque. Thats it.

It´s the hydraulic clutch system where the brake fluid turns black soon. But nobody knows why...

There are electric brake fluid testers available, cheap. Buy one.

If TUV changed there recommendation to 4 years would you go that long? Apparently oxidation of copper is a better indicator of the condition of brake fluid and it seems that the fluid can go well past 2-3 years. Obviously if one only follows this method then brake components would probably never get looked at.

 

[Falcon_LS]

From one neglectful extreme to

a pathologically OCD extreme. Only on BITOG.

My car, my money. I don't see where the problem is.

Plus I operate my vehicles in a completely different environment than most folks on here.

 

[atikovi]

Care to explain how I stated that one should go 10 years and not change brake fluid?

Most cars go 10-20 years without changing,

 

[supton]

And...?

 

[atikovi]

Huh...?

 

[slo town]

I knew what you meant, supton.

Scott