Brake Fluid Question.

That's odd. Should be same colour as the bottle it came with for few months at least. If your OCD is in full effect, mind as well change it, maybe you didn't do correctly on one line. If not do it again sooner then later like on 24th month instead of procrastinating for years on without servicing.

Fluid is incompressible so it's not like the new fluid you observe in the reservoir has mixed with any residue further down.

The incongruity may have something to do with the relative levels in the reservoir before and after the flush.

That is, before you flushed the level may have been down a bit because of pad wear.
After the flush, the level in the reservoir is higher and viewing it through the plastic reservoir makes it look more yellow than it really is.
(Of course, it is usually recommended that you fill back up only to the level it was before so as to maintain a visual clue of pad wear progressing.)

Just a theory. But I wouldn't obsess over it anyway. Even if it was an incomplete flushing of fluid, that is way better than nothing at all.

DJ Trance AZ wrote: ↑ I flushed the brake fluid in two cars using a hand pump kit about three months ago.

I noticed that in one of the cars the brake fluid color has turned to a slightly darker yellow (DOT 3 fluid) as observed from the reservoir. The fluid level, however, remains at the same level. The braking response remains firm and responsive.

What are you thoughts about this? I was wondering if I need to do another flush again or if I will be wasting the fluid... being an OCD doesn't help either...

Much appreciate your input.

Most fluid will change colour over time not due to dirt but rather moisture - the darker the fluid, the more moisture in a generic DOT 3/4 brake fluid. The car with the slightly darker fluid may have been exposed to wetter conditions (especially around the engine compartment) than the other car.

Much appreciate your input. I should get one of those brake fluid test pen to check for moisture level.

DJ Trance AZ wrote: ↑ Much appreciate your input. I should get one of those brake fluid test pen to check for moisture level.

You can also check brake fluid with a multimeter.

Lots of instructions but these came up first and they all seemed to be generally the same technique

https://www.linkedin.com/pulse/motor-ve ... l-mucevski

https://www.rvnetwork.com/topic/134413- ... vom-meter/

Perhaps I should check the moisture level at the reservoir, and drain a bit of fluid from the line for checking too...

DJ Trance AZ wrote: ↑ I flushed the brake fluid in two cars using a hand pump kit about three months ago...7

How old was the original fluid before the flush?

billford wrote: ↑ How old was the original fluid before the flush?

The two cars had about 38,000km prior to flushing the brake lines.

Thanks again for all your input

DJ Trance AZ wrote: ↑ Perhaps I should check the moisture level at the reservoir, and drain a bit of fluid from the line for checking too...

If the flush was complete and the calipers are in good shape, you should see the highest moisture content in the reservoir as that fluid is constantly exposed to air.

DJ Trance AZ wrote: ↑ The two cars had about 38,000km prior to flushing the brake lines.

Thanks again for all your input

38,000 km is still pretty new in most conditions. How dark was the old fluid - ie are we talking a pale ale type or more of a darker beer colour?

craftsman wrote: ↑ 38,000 km is still pretty new in most conditions. How dark was the old fluid - ie are we talking a pale ale type or more of a darker beer colour?

Pale Ale is quite perfect in describing the color!!

Just like many things, you can't determine the quality based on its colour.
And just like 50 other previous threads about how people leave their fluid drain for +8 hours, you will never able to get "all" the old fluid out.
It is normal to have a little bit of old fluid mixing with the new fluid.

BDSL wrote: ↑ Just like many things, you can't determine the quality based on its colour.
And just like 50 other previous threads about how people leave their fluid drain for +8 hours, you will never able to get "all" the old fluid out.
It is normal to have a little bit of old fluid mixing with the new fluid.

That's true that you can't definitely determine the status based on colour... however, you can tell one important thing - generic brake fluid starts off life basically as a clear very light yellow in colour (almost like a light vegetable oil in colour) and as more contaminates get mixed into the fluid the colour goes darker. You can almost guarantee that a dark brown or almost black brake fluid is in worse condition than one that is pale yellow.

DJ Trance AZ wrote: ↑ Pale Ale is quite perfect in describing the color!!

That's actually not too bad and is aligned with the mileage you are at.

DJ Trance AZ wrote: ↑ The two cars had about 38,000km prior to flushing the brake lines.

Thanks again for all your input

How many months or years is that? There's usually some sludgy deposits that sits in the bottom of the reservoir that flushing doesn't remove. The older the fluid is, the worse it gets. Once the reservoir is empty you can see it at the bottom.

It doesn't really affect anything because it doesn't move, it can affect the color.

I gravity bleed a litre though my system once a year, it keeps it clean.

So I just tested the fluid in the reservoir and it shows about 1-2% of water present...

DJ Trance AZ wrote: ↑ So I just tested the fluid in the reservoir and it shows about 1-2% of water present...

Test the fluid from a new sealed bottle.

billford wrote: ↑ Test the fluid from a new sealed bottle.

So tonight I opened a new DOT 3 bottle and poured about 30cc into a dry clean cup... Used the same pen (wiped clean from prior use) and also showed 1-2 % of water present...I am thinking the pen is inaccurate...