Flush and replace brake fluid at 15K miles??

[TimLee]

Nissan changed to a two year interval on all their vehicles.

Is it overly conservative, Yes.

But I have done it to keep up with the warranty requirements for my seven year warranty.
If the main component fails it is extremely expensive as teported by someone else in another thread.

Reminds me I need to have my 2009 Altima done.
Never been changed.
About time at seven years

 

[RockyNv]

I have been maintaining cars/truck for over 40 years and the standard is to flush brakes every 2 years. This becomes more critical with ABS and Traction Control Systems as the pump and computer controlled valve blocks can be damaged from water absorbed by the hydroscopic brake fluid turning it acidic. More critical than the fluid that remains more fresh in the brake resevoir is the stale fluid that pools in the extramities of the system where it is also subjected to more heat. In a cool dry climate you may get away with skipping a few flush intervals however to play it safe with a modern ABS/Traction Control System you flush at least every two years. You at times will be shocked at what the fluid in the brake calipers and the lines a few inches back from them can look like compared to whats in the master cylinder.

When you flush you should not use brake fluid from a container that has already been opened as that fluid started aging/absorbing water from the moment the seal was broken the first time the cap was removed. Always flush with fresh fluid from a new container. After the container has been opened its good to put the date on it and only use it to top off the system it was used to flush/refill and dispose of what ever is left when the two years are up and you flush the system again.

Remember its not miles but years. Brake fluid absorbs water regardless of how many miles are driven.

 

[AlGrsn]

The reason for changing brake fluid at 12 months / 15,000 miles / 24,000 kms is that it heads off problems with the antilock brake / traction control pump, which costs thousand$ to replace and is not repairable in the field.
Combustion powered cars have engine drag braking, transmission downshifting, hydraulic service and mechanical parking / emergency brakes.
The Leaf, like other electric-only cars, has regenerative, hydraulic service and mechanical parking / emergency brakes. If the regenerative braking blows a fuse, trips a circuit breaker or otherwise fails, there is no significant drive motor and reduction gear drag. Because of this it is fitted with larger front brake pads than a comparable gas car.
Almost all cars’ parking / emergency brakes are on the rear wheels only. On a FWD car with only the driver aboard, the rear tires have very little grip, about half as much as the front tires, so rear wheel brakes don’t do very much in an emergency.

 

[dsevier]

I have owned otherwise well maintained cars that have not had brake fluid changed by previous owners and when I replaced it, it has looked like dark tea at best and Guiness stout at worst. As others have mentioned, the hygroscopic fluid absorbs water but over the years and that can lead to rusting of cast iron or steel components like calipers and pistons. And it can make the finicky and expensive ABS system unhappy. I live in a desert where ambient humidity is 15% in the summer. So I will change mine every 3-4 years. I have a tester and it will show the water at 1% when new and 1-2% a few years later. Also, what's in your reservoir is not necessarily what's in your calipers so I change at 2%. But the idea that brake fluid is good for the life of the vehicle is wrong.

 

[LeftieBiker]

But the idea that brake fluid is good for the life of the vehicle is wrong.

I haven't read every post. Did anyone actually write the above..?

 

[dsevier]

There was a discussion on the first page as to whether this was a legit maintenance item after 5 years and the opinion that the only maintenance needed was cabin filter changes and tire rotations. I apologize if I misconstrued that to mean for the life of the car.

 

[dsevier]

I just replaced my brake fluid on our 2014 Leaf with 66k miles. I did not see any record of this work having been done by previous owners. The old stuff was pretty dark, which did not surprise me. I used a brake fluid tester to see how bad things were. The old fluid in the reservoir had 3% moisture, the fluid first coming out of the caliper nipples had between 3-4%. Well, I say at least 4% as that is the highest level that can be measured and it could have been higher. When replacing, I measured the moisture of the fluid coming out of the nipples periodically until it measured 0% (new). I needed 2.5 bottles of the Nissan DOT3 fluid to complete the job, using about 500 ml to replenish the reservoir after draining and getting fresh fluid out of the right rear, which is the first according to the service manual for '14. I used about 100ml for each of the fronts and about 150 ml for left rear.

A couple of takeaways. One is just how much difficulty I had with emptying the reservoir. I could get out the top 1/3 but the old stuff stayed in there. If there is a trick I could not figure out, please share. The other thing is that I tried to pressure bleed the car but struck out. With other cars, I would have the car with ignition off, put the cap on the reservoir, pressure it to 15 psi, open a caliper nipple and away I'd go. With the Leaf, I noticed I got just a bit of fluid and a lot of air out of the first nipple but the reservoir level did not drop much. So I switched to the using the brake pedal to move the fluid. Again, if I am missing something, I would love to know.