Confirmed Brake Fluid is lifetime! Save your money

[ftgambit]

Full disclaimer:I am simply sharing my opinion based on my experience with my BMW X5 3.0i, I am not responsible for anyone attempting to not change their brake fluid for the life of the vehicle.-------
Thats out of the way, I just wanted to post a brief commentary based on my vehicle hitting 205K miles. I had been running a sort of experiment, I do about 80% of all maintenance on my SAV. Only exception to that it is when I had my transfer case replaced, because I do not have the equipment or tools for major repairs. My engine and trans are still original and in excellent condition, except for an oil leak in the oil filter housing gasket and oil pan. I replaced my Front brakes and rotors with BMW original and my rears with aftermarket. Will save you a few bucks while still giving you that BMW brake bite one is accustomed to. So to the point of my post, I have not replaced the brake fluid since the car was purchased From a dealer as a CPO in 03. I would guess the stealer never swapped it out either. I have lived in Las Vegas,N CA and S CA for the past 10 yrs, to give you an idea about climate, taken it to the snow briefly several times and Vegas gets pretty good extremes for weather, more heat than cold. I cannot speak to Wisconsin or Minnesota winters, as that may affect fluid performance and characteristics. But for the rest I am going to say in my opinion it is not necessary to ever replace or flush your bmw brake fluid. Unless you get a leak or contaminate the fluid by opening the reservoir. My brakes still work as good today as they did when I bought the truck. I still have the original calipers and brake lines, was thinking of replacing those soon as they look weathered.
If someone can suggest a facility I can send a small fluid sample to evaluate the condition of my fluid I would be happy to. Im here to share what I think was a myth propagated by bmw and other auto manufacturers for decades to scare people into performing unnecessary maintenance. I feel my vehicle has provided a fair test platform to merit this claim as I drive it every day. If anyone has a different experience please post And share your thoughts. If you just want to troll dont bother Im simply sharing my experience given the listed circumstances.

[admranger]

Visualize using paragraphs...

You can buy a brake fluid moisture meter on Amazon. They aren't that expensive.

Living in a relatively dry, benign environment will allow brake fluid to last longer. If you lived up in the frozen northland with it's higher humidity day in and day out, you'd get to experience a frozen caliper in the winter, either due to rust or the fluid freezing. BTDT.

[ants_oz]

Brake fluid is hygroscopic - it absorbs moisture present in atmospheric air.

BMW do not use some fancy, new technology brake fluid - they use the same specs as everyone else.

Brake fluid WILL absorb atmospheric moisture over time - the rate at which that moisture is absorbed will depend on several factors.

Moisture in brake fluid will have several adverse effects on the effectiveness and serviceability of the braking system.

All of these are factual statements, with easy to verify scientific evidence available.

Brake fluid does NOT have a "lifetime" rating, however there are plenty of vehicles running around out there in the world with systems that have never been flushed or bled. Is that wise or good practice? No. Simply because your hydraulic braking system is one of the most important safety systems on a vehicle.

This is the statement of a qualified mechanic with almost 30 years on motor vehicles.

But if you want to risk it all to save a few bucks every few years, hell, fill your boots. Might as well stop changing your engine oil at the same time, and don't ever bother checking your tyre pressures either - after all...there are some people out there in la la land that done bother with things like that either.

[Joshdub]

^ Bingo.

Seriously, is ~$15 every couple years too much?

[ftgambit]

Antz and Joshdub thank you for posting. I change my oil every 5K just to clarify and please dont compare engine oil to brake fluid thats just silly. You reinforced my point exactly, BMW brake fluid is not labeled as a lifetime fluid yet it has held up as good as one. I'm not questioning the properties of BMW fluid being special, its obvious to anyone its the same as any quality brake fluid.
Again for the majority of owners that live in the regions I have lived, a fluid replacement may be an unnecessary expense that is all I am stating. Now $15 that's just absurd call any indy shop or dealer and ask what brake flush and fluid replacement runs closer to $200-300 in CA quite a bit more. That money can be better spent on other maintenance, and if you worried seems like once every five years for preventive care would suffice. Again just my opinion.

[ants_oz]

Mate, you've got your opinion based on....I dunno what basis it's on....I've got my opinion.

Our opinions appear to differ. WIDELY.

No skin off me if your brake system fails due to lack of service mate, we live on different continents

[lhordmclain]

vehicle under maintenance/warranty or extended maintenance/warranty, the dealership will do brake fluid service maintenance.

For vehicles out of warranty, dealership cost is top dollars

versus independent shops will typically charge an hour (approx 100) + the cost of the DOT4 fluid

versus DIY the cost of the DOT4 fluid, tools investment and time.

For safety reasons, I'm a firm believer to do this every two years or 30k miles which ever comes first. Also, when the vehicle is due for changing pads+ rotors+sensors.

[crystalworks]

I'm with most here... but don't do it as frequently as above. A brake fluid flush along with soft line replacement is a great way to maintain the health of your ABS pump, calipers, and master cylinder if done every 3 or 4 years. If you do 20,000 miles every year... do it every 3 and less if you drive less.

You may think your system is working as well as when you bought it... but you'll never know for sure until that panic stop where your ABS doesn't stop the truck as quickly as it should for one reason or another.

As stated... even if paying someone $200 for a fluid flush... or $300 for a fluid + soft line replacement... it's a helluva deal for the safety benefits afforded. That's only $300 every 3 or 4 years. And if you do it yourself... then it's only $20 every 3 or 4 years.

[bestvaluestore]

Nice to know.So,it is recommended to flush it once in every 30k miles?I've never flushed mine too.It's been probably like 7 years now.Everything works well,even abs is ok,recently I had to stop suddenly and does the job pretty well.

[ants_oz]

For the education of those who were unaware - as moisture levels increase in the brake fluid, the fluid loses its resistance to boiling. Brake fluid most often boils in the calliper, immediately behind the piston/s as heat is transferred from the pad friction material, to the steel backing plate, and into the piston. And when it boils, there is often no warning. Your brakes just "go away". One moment you are braking well, the next you are on a sled without brakes. But with a steering wheel...