Is it necessary to replace brake fluid on a car every 3 years?

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IowaFarmBoy
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Joined: Fri Jan 22, 2010 8:19 am

Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by IowaFarmBoy » Sun Apr 15, 2018 8:40 pm

I try to do it every 3-4 years. Our older Volvos have it in the maintenance schedule for every 3 years or 30k miles if my memory is good. Our new Toyota is something like that also.

In addition to safety concerns, I do it for protection of the system. Modern anti-lock systems have some expensive components and flushing should help prevent corrosion.

inbox788
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Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by inbox788 » Mon Apr 16, 2018 2:23 am

Woodshark wrote:
Sun Apr 15, 2018 4:53 pm
Over the course of time, I did notice that it was getting harder and harder to stop but, it being a lightly and seldom used vechicle, I ignored it. ...I was shocked to see that the old brake fluid was the color of Coca-Cola. One hour and a large bottle of new fluid. Problem solved.
Could you see that in the reservoir? I've never noticed a major color change through the plastic and on occasion will open up and look directly inside, and I've never noted anything close to coca-cola color. New cars are nearly clear and older cars a little yellow. I've sometimes worried a little it's worse at the brake piston, but not enough to do anything about it. FWIW, I regularly test my brakes and so far so good. Note to self, DO NOT ignore when braking is getting harder to stop or if brake fluid looks like Coca-cola. Those are reasons to take a look at the fluid in the lines. And I figure if it's been years and I bother to bleed the fluid and check the line at the pistons, most of the work was already done and I might as well finish and exchange all the brake fluid.

ssquared87
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Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by ssquared87 » Mon Apr 16, 2018 2:51 am

Honda does not make money by selling you brake fluid. They make money if you live long enough to buy another Honda.

Follow the owners manual. Many posters correctly note that brake fluid absorbs water over time/use leading to weaker and weaker braking effectiveness. The change is gradual over a long period of time so you may not realize its happening until one day you hit the brakes and nothing happens as some previous posters have experienced.

Aside from safety, not flushing the brake fluid can lead to corrosion issues and frozen calipers etc.

Many manufacturers (i.e. the reputable ones) have a brake fluid service recommendation. I'm surprised to learn from one of the posters above that Toyota does not include that in their maintenance schedule. Their vehicles are not immune to the laws of chemistry. Guessing they don't recommend it because they want to make it appear as if their cars require less maintenance, but who knows.

neilpilot
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Location: Memphis area

Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by neilpilot » Mon Apr 16, 2018 8:13 am

inbox788 wrote:
Mon Apr 16, 2018 2:23 am

Could you see that in the reservoir? ................. Those are reasons to take a look at the fluid in the lines. And I figure if it's been years and I bother to bleed the fluid and check the line at the pistons, most of the work was already done and I might as well finish and exchange all the brake fluid.
While there are obvious differences, the brakes on my airplane are very similar to a car. A reservoir, master cylinder and brake calipers on 2 wheels. A few years ago when I bought my current airplane, the fluid in the reservoir looked fine and my pads were OK but braking was anemic. We had our mechanic flush the brake fluid. The old fluid that initially came out of the bleeders looked like an emulsion and was almost the consistency of toothpaste. That was the result of many years of exposure to atmospheric water and exposure to heat generated during braking. Once the "paste" had bled from the calipers, the majority of the old fluid looked dark but entirely fluid. After the flush, I had great braking.

I would submit that a brake system on an older car that hasn't been flushed or that was treated to the turkey baster reservoir flush is similarly likely to suffer from fluid degradation at the calipers.

alfaspider
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Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by alfaspider » Mon Apr 16, 2018 8:22 am

Over time, brake fluid will absorb moisture from the air. Even though it's more or less a sealed system, some water vapor will seep in through the reservoir or fittings. Water in the brake fluid leads to a lower boiling point, which increases the risk of boiling your fluid under repeated hard braking (such as going down a mountain pass or a performance driving situation). Additionally, water in the fluid will cause internal corrosion in the braking system. In severe cases, brake lines can rust from the inside out, leading to a brake line that looks fine on the outside but prone to rupture.

So that's why you replace your fluid. The question is when? For normal daily-driving usage, most people are probably fine with more like a 5 year schedule, and I am willing to bet a huge percentage of 10-year old cars have never seen a brake fluid change. For a car that's going to see heavy brake usage (performance driving, trailer towing, or mountain driving), a 3-year schedule makes sense. For a car that will be driven on a race track, fluid should be changed at least every other event or so (and bled after every event).

I've used a Motive Power bleeder for brake fluid changes on my car- it eliminates the need for a helper. Only downside is you need a new cap when using it with a different car. I've spent more on caps than on the tool itself.

Woodshark
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Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by Woodshark » Mon Apr 16, 2018 4:27 pm

inbox788 wrote:
Mon Apr 16, 2018 2:23 am
Woodshark wrote:
Sun Apr 15, 2018 4:53 pm
Over the course of time, I did notice that it was getting harder and harder to stop but, it being a lightly and seldom used vechicle, I ignored it. ...I was shocked to see that the old brake fluid was the color of Coca-Cola. One hour and a large bottle of new fluid. Problem solved.
Could you see that in the reservoir? I've never noticed a major color change through the plastic and on occasion will open up and look directly inside, and I've never noted anything close to coca-cola color. New cars are nearly clear and older cars a little yellow.
If memory serves, the fluid in the reservoir was slightly off color but not near as dark as the fluid that initially came out at the calipers. That would make sense, since there is no recirculation in the brake lines and anytime you top off the fluid, it tends to remain in the reservoir for awhile.

alfaspider
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Joined: Wed Sep 09, 2015 4:44 pm

Re: Is it necessary to replace brake fluid on a car every 3 years?

Post by alfaspider » Mon Apr 16, 2018 4:32 pm

Woodshark wrote:
Mon Apr 16, 2018 4:27 pm
inbox788 wrote:
Mon Apr 16, 2018 2:23 am
Woodshark wrote:
Sun Apr 15, 2018 4:53 pm
Over the course of time, I did notice that it was getting harder and harder to stop but, it being a lightly and seldom used vechicle, I ignored it. ...I was shocked to see that the old brake fluid was the color of Coca-Cola. One hour and a large bottle of new fluid. Problem solved.
Could you see that in the reservoir? I've never noticed a major color change through the plastic and on occasion will open up and look directly inside, and I've never noted anything close to coca-cola color. New cars are nearly clear and older cars a little yellow.
If memory serves, the fluid in the reservoir was slightly off color but not near as dark as the fluid that initially came out at the calipers. That would make sense, since there is no recirculation in the brake lines and anytime you top off the fluid, it tends to remain in the reservoir for awhile.
I'd just point out that you should never have to "top off the fluid." The fluid level will drop as brake pads wear, but any OEM reservoir should have sufficient capacity that there is enough fluid even if the pads are completely worn out. Topping off disables an important safety feature because excessive pad wear will not trigger a low fluid warning light.

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