Hi Everyone,

Im in the process of taking my car to my mechanic to change the Front and Rear Pads/Rotors on my vehicle and wondering about if I should also replace the Brake fluid. Car has only 35,000 miles.

Thanks

 

The deterioration of brake fluid is time-dependent, not mileage dependent, and ~6 years is a long time. This is typically a controversial topic, and someone will often report their 20-year old vehicle still has the original fluid and stops just fine .

I recommend you read this article, and then decide for yourself. A fluid replacement during brake service should not add more than US$100 to the cost of the job.
Bendix provides an insight into the importance of Brake Fluid - Issue 12 | Bendix Brakes

 

I agree with n0v8or. Six years is a long time. I would definitely have it done.

Personally, I only use OEM fluid in my Lexus' brake system.

I drive appx 20-25k/year, mostly highway. Still I purge/fill my brake fluid appx every 2/3 years - depending on my availability. Oh, by the way, I do it myself

One of the things I ALSO do BETWEEN those intervals, perhaps a couple times a year, is the following:

With the vehicle cold and on a level surface:

• Have a bottle of new fluid handy, in close proximity to the brake fluid reservoir (near master cylinder).
• Place a cloth rag in the area surrounding the reservoir.
• Have a bottle or container available for old fluid, close proximity to reservoir.
• Open the reservoir. Use a turkey baster or Mix Mizer (Walmart ~$3).
• Syphon out a few ounces (perhaps 4) and empty into bottle/container.
• Do this at least a couple times, but not TOO many times. Ensure that you don't completely empty the reservoir, which could let air into the system!
• Replenish the removed fluid with NEW fluid.
• Do this a few times in succession, depending on time, miles and 'how often you brake'. In other words, I would do this N times, until the small (16oz ?) bottle of brake fluid is emptied.

Some words of caution:
1. Don't keep your reservoir open to air any longer than necessary. As soon as you're done, first thing, close it. Same for your new bottle of fluid.
2. Make sure you close TIGHTLY your bottle of new fluid.
3. I'm not sure of shelf life of brake fluid. Even though it's more expensive to buy the smaller bottles, I DO because I want to use it up ASAP, so as to not have an 'opened' bottle on my shelf too long.
4. I use a glass jar for the old fluid so I can easily see the condition of the old fluid. BEWARE: The visual of the fluid is NOT a conclusive determinant of the effectiveness/condition of the fluid. It may tell you something, but not the whole story.
5. Do your best to NOT get this fluid onto anything, except the rag. It is very strong and can easily eat into your paint and other stuff (i.e. clothing).

 

Here are some things to know:

1) brake fluid is very hygroscopic, meaning it readily absorbs water, and this degrades the fluid.

As a result, it is best to buy fresh sealed bottles, and not store half used bottles, nor use bottles that have been opened and stored for an extended period.

2) As you should (or must) bleed the system when replacing brake components, it is trivial to also replace the existing fluid with fresh fluid. Brake fluid should be replaced every two years.

3) Brake fluid is not particularly expensive, and importantly, the brake system is not a place to try and save money.

 

If they are changing the pads and rotors, then it's super easy to change the fluid. When I changed out both the front and rear pads along with rotors on my wife's 2018 NX several months ago I completely exchanged the brake fluid. It was very easy to do using TechStream but did require two people. She had to pump the brakes while I undid the bleeder screws and went around the car. I used almost an entire bottle of fluid in the process. So all the old fluid 100% was removed and the new fluid replaced it.

Fluid is cheap and if you are replacing everything else then 100% you should be getting the fluid changed. Just as mentioned it's hygroscopic and as time goes on it will continue to absorb moisture.

-Nigel

 

It can be done with one person, using a vacuum brake bleeder tool, available at HarborFreight for not much:

Hand vacuum pump $26: https://www.harborfreight.com/brake-...kit-63391.html
I still have my MityVac I bought 35 years ago at PepBoys for $50 (LOL), and this method works great, but you do need to make sure to top off the master cylinder so that it does not run dry,

Vacuum pump with auto-refill tool $30: https://www.harborfreight.com/brake-...der-92924.html
This pump requires a source of shop air, but it comes with an auto-refill reservoir, so you don't have to lower the vehicle to refill the master cylinder. It's on sale right now for Harbor Freight members for $24.

Techstream or an OBDII is still needed to actuate the solenoids in the ABS/actuator.