Yes, mileage means nothing, brake fluid attracts moisture, and it can get nasty, I replace mine yearly on my bikes and Corvettes, my daily driven cars and truck every 2 years regardless of miles or 25K miles usually for me.

 

I've been told by a mechanic that in a very dry climate (Phoenix AZ) it is not necessary.

I did do it for my Macan though.
I only did it once or twice for my Jaguar. I was told after the 1st brake fluid flush after 5 years ownership that the brake fluid looked just fine.

So, for most people in most climates, the answer is yes, follow the manufacturer recommendations.

If you always drive in a dry climate, IDK. Probably can get away with extending the time interval.

 

Being a motorcyclist I have learned to error on the side of caution when it comes to brake fluid flushes. Your eyes will get really big if you as captain call down to the folks in the engine room to reverse the propeller and they say maybe not unless you give us a raise.

 

It also depends on the type of brake fluid.

DOT 3 brake fluid does not attract water as much/quick as DOT 4 fluid. DOT 5 fluid is silicone based and doesn’t attract water al all, i.e., immiscible with water.

Macan uses DOT 4 fluid so the need for flushing every 2 years.

 

Water does not mix in DOT 5 fluid, but that doesn't prevent moisture (water) from entering the system. I've used it in a classic car for long-term storage only to find a small puddle of water in the master cylinder under the DOT 5. Since it was a cast iron reservoir, the bottom was covered with rust.

Think of water and oil; they don't mix and the oil sits on top in a distinct layer. So any low point in the system can and will eventually have water collect there.

 

$350 to flush the brakes is highway robbery, imo. You can use a pressure bleeder and DIY in a matter of half an hour including setup.

 

And if you are not the DIY type, I would think most independent garages would quote you $100 or less for the job. It’s a similar job to just about any other car, no special tools needed. $350 is just plain silly.

 

Mines is 2yrs old and I hit 16,000 miles. I went to an indy shop, and it was just under $200 for the job. My mechanic told me, the brake fluid looked a little brown.

 

I just had mine done at a Porsche specialty repair shop. 2 years old, 16,000 miles. $125 for all. It just isn't worth gambling for such a small cost , compared to the cost of new master cyl. or calipers.

 

At 2 yrs, my wife's S had only 14,000 miles; service adviser said no need to flush brakes, so I didn't. At 2yrs, my GTS had 19,000 miles; service adviser suggested flushing, so I did. This is in sunny, dry Tucson. I think in most areas, following the mfg recommendation is advisable, whether at a dealer or indy shop.

 

I’m always game for tinkering with my car. I’m also not afraid of the flame throwers I’ll get for this....

I change the brake fluid from the top side using a 60cc syringe, catheter tip for those in the know. It simple to pop the cap off. Pull the filter thing out, and suck the old fluid out. I use old oil jugs or brake fluid containers to hold the old fluid. Once sucked out I fill back up and replace the filter and cap.

I’ll repeat this process for each gas fill up until the jug is gone....about 3 or 4 fill ups. This gives the fluid a little time to circulate. Is the fluid ever 100% new? No. Is changing the fluid every 2 years a bit aggressive? Yes. This method has always worked well for me and seems to fit into the bell curve of expected real world use conditions.

I figure this method saves me about $100 every 2 years which pays for the spark plugs, brake fluid, and the beer for each project.

Ok...now I’m sure I’ll need my flame suit for a bit.

 

The amount of fluid in the reservoir is nothing compared to the amount in the lines. Additionally, it doesn't circulate, there are no loops in the line for the brake fluid to get back to the reservoir.

Also, you can get a brake fluid tester off amazon for $10-20, checks moisture content in the fluid so you know when to change it. I have the OTC one myself.

 

I'm due for 4 years service but will have < 30K miles. @ 2 years I paid dealer for brake flush.

I see these electronic testers are only ~ $10. So, Since I live in a dry climate, I may buy one & test my fluid.

Maybe I only need to change brake fluid here every 3 , 4 or 5 years?

My question...

If there is 0 moisture in my brake fluid, do I ever need to change it?

What else, besides moisture, goes "bad" with old brake fluid?

 

If there is 0 moisture in my brake fluid, do I ever need to change it?

Would it get dirty over time like power steering fluid tends to? Not sure.

I've seen suggestions that hydraulic power steering fluid be changed every 5 to 7 years as it becomes dirty and therefore abrasive. Seems to make sense although I've never seen a vehicle manufacturer call for this in their maintenance schedule.

And the next question is does the electric power steering used on many if not most newer cars use any fluid at all that it would make make sense to replace at some point? Don't know the answer.

 

If there is 0 moisture in my brake fluid, do I ever need to change it?

Maybe, maybe not. At two years a dealer said no need to change the fluid in my 911. But they did at 3 years. Part of this might be the ABS. Those complaining that the "never had to do this before", were they in pre-ABS days? From 2005 Despite the talk, brake fluid is not forever https://www.chicagotribune.com/news/ct-xpm-2005-11-20-0511200182-story.html

"ABS is very sensitive to foreign matter in the hydraulics. The foreign matter comes from corrosion in the brake system. ... Though there are corrosion inhibitors in the fluid, they wear out over time; up to 90 percent is gone in as little as three years."

I can believe this. Nothing is forever. Brake Fluid is a consumable.

In this day and age, we are still using stone age technology brake fluid. I wonder what's so hard to come up with fluid that does not absorb moisture.

DOT 5 does not absorb moisture. Why doesn't Porsche use DOT 5? I guess you have to ask Stuttgart.

I doubt very seriously changing the brake fluid is as critical as some make it out to be. It's not a bad idea, to be sure, and for a car that sees track duty, it should be considered a mandatory maintenance item.

But is it really necessary for a street only car?

... looking through the manuals for my Nissan and my Kia, neither has any requirement listed to ever change the brake fluid under any circumstances. The only mention of brake fluid in the maintenance manuals is simply to check the level. So, if changing the brake fluid was truly a life saving maintenance item, and you're going to die in a horrible wreck if you don't change it, there would be universal consensus among manufacturers as to the idea of changing it along with required intervals.

Brakes are about THE most important thing on the car. Porsche takes it very seriously. You can look it up but they are serious about testing them. They are always more powerful than the engines. Water in the brake lines means the boiling point goes down. According to this article, 3% water in DOT 3 means a drop of 100 degrees in boiling point. Since Porsche is a performance vehicle, I'll guess they expect people to drive hard and brake hard. Sure, some people buy status symbols but as Ferry Porsche once said: "My cars are meant to be driven, not polished". If water in the fluid, the brakes will fade and then ... crash.

Those Kias and Nissans? Who drives them hard? Who brakes hard on the street? Only in an emergency? So, what is the probability of person A in a Porsche and Person A in a Kia braking hard, day after day? Have you ever seen anyone really use their brakes in a Nissan or Kia? I don't mean once in a great while because of an emergency but brake hard in turns or coming up at lights?

One of the things you learn, and I'm not 100% sure about the Macan but it probably is, but I know it for the 911, is that the brakes are very, very good. VERY good. They are so good that coming up to a light, I purposely keep looking in the rear view mirror because although I knew I could stop in time, that was not true for the person behind me. This wasn't a one time thing. It's ALL THE TIME. Every light, every stop, always look in the rear view mirror.

Brakes don't fail very often. Per the NHTSA in 2015, usually, by a wide margin, its driver error but 2% for mechanical failure. Of that 2%, 22% was for brake failure. They don't break it down anymore than that so for all crashes recorded and documented in that year, .0044% were due to brake failure, ~10,000. It doesn't say "why" the brakes failed. It could be a defective part, brake fade, mechanic error. Who knows. So this is where the numbers come in and this is speculation but I'd bet you could look this up and find something from people who do crash forensics or insurance companies.

The carmaker, tells you the maintenance to do. You think its a scam. "I ain't paying for that. They just want my money". And then there is my favorite that is expressed in this forum over and over again.

"But my (Kia, Toyota, VW, .... car) never did this". This is repeated over and over again. Different subject, same tune. Then go buy a Kia, Toyota, VW ...

So, you don't have the fluid checked out and water has gotten into the fluid. One day, you're trucking down the interstate doing 75, whatever the speed limit might be and some construction comes up fast. You brake HARD. All is OK. You slow down to a stop, then traffic flows again. But construction is constant. You brake hard again from 75 and then get back up to 75 and ... a deer runs across the road. You brake HARD again and .... mush ... crash.

Whose fault is it? Did the brakes have a faulty part? Or did that driver just ignore the maintenance schedule. When the crash forensics are done and the conclusion is water in the brake fluid, who is to blame? Porsche? Did Porsche build defective brakes? Your mechanic? Did the last mechanic who worked on the brakes do something wrong? Or the owner? Did the owner decide brake fluids were a scam and chose to ignore them? Who will be assigned responsibility for the brake failure? Now imagine it wasn't a deer but a minivan full of kids. Are you feeling lucky today?

It's a couple hundred dollars. It's a couple nights out for a fancy dinner for two every other year. Why is anyone questioning this?

My suspicion on why its not in a Kia or Nissan manual? Who drives them and how do they drive them? Its a numbers game. How hard do those drivers brake vs Porsche drivers? What are the probabilities? Is the driver in a Kia or Nissan traveling at high speeds the same as the Porsche driver and braking as hard from higher speeds?

 

Brake fluid attracts moisture, brake fluid is very corrosive, heat effects the fluid just as it would any oil/fluid.

There is a valid reason to keep it fresh every two years, if you do not adhere to the recommended schedules for service PAG may deny a warranty claim in your brake system due to service neglect.

Its under $300 at the dealer and its then documented in their system, I could have changed mine myself last year, but it would not have been noted in the Porsche system as to the date and mileage it was performed, so I had them do it so that it was documented.

Some things you just get done, its a upfront cost to ensure a down the road warranty on the brake system.

 

My question has nothing to do with warranty.
I realize that if everyone tested their brake fluid @ 2 years, the vast majority would have moisture. IDK if it would be 1%, 3% or 5%. So, it is a moot point for most.

Maybe some would be able to change it every 3 years if not living in a humid climate

I was wondering about literally same moisture content (0%) @ 2 years as just after changing the fluid.

Everything I can find in Google searches talks about moisture.

I think a lot of scheduled maintenance items are questionable. Not whether to do them but WHEN. Especially the ones that have time & mileage, whichever comes 1st.

For me:
Oil is easy, synthetic every 1 yr. even if put on only 5K miles. (Yes some want to analyze their old oil & change it every month

Engine air filters s/b mileage & not time. A Garage queen’s air filters are NOT getting dirty sitting in the garage!

Spark plugs, also mileage, not time. I’m going to do mine @ 30K miles Which will be > 4 years. (Porsche mechanic also said he thinks that is OK)

PDK fluid? IDK I asked a Porsche mechanic & he reiterated the official position of 4 yrs. or 40K whichever comes 1st but admitted if it was his car, he’d wait till 40K miles. I’m not sure yet what I’ll do.

Wipers? Give me a @##$***!! break! Whenever I do not like how they wipe, LOL. Probably s/b changed every 6 months in this heat <GRIN>

 

Makes perfect sense and refreshing brake fluid is one of those items many, among the non-enthusiast ranks, are not even aware of.

 

With the small price paid to change your brake fluid and we are talking about a premium priced vehicle, I really don’t get why this topic even gets discussed

 

You're discussing it. Why?

 

Anything that's not required service in the manual, I tell my service dept(s) to get bent unless they can make a REALLY compelling case for it.

 

If you live in a dry climate, do the flush every 3 years. Otherwise, every 2 years.

I live in a relatively dry place with not much rain & no snow so I do it every 3 years for all my cars. Never a problem.

 

I doubt very seriously changing the brake fluid is as critical as some make it out to be. It's not a bad idea, to be sure, and for a car that sees track duty, it should be considered a mandatory maintenance item.



But is it really necessary for a street only car?


Consider this: Every manufacturer has maintenance schedules for the vehicles they make, ALL have engine oil & filter changes required, trans oil changes, diff oil changes, coolant changes, and transfer case oil changes. Pretty much all agree on changing engine oil, some list transmission & differential oil as optional depending on operating conditions, same for coolant intervals, etc. However, there is little agreement as far as changing/flushing brake fluid. We all know Porsche and Mercedes recommend changing brake fluid every two years, as do most motorcycle manufacturers. However, looking through the manuals for my Nissan and my Kia, neither has any requirement listed to ever change the brake fluid under any circumstances. The only mention of brake fluid in the maintenance manuals is simply to check the level.



So, if changing the brake fluid was truly a life saving maintenance item, and you're going to die in a horrible wreck if you don't change it, there would be universal consensus among manufacturers as to the idea of changing it along with required intervals. Since it appears not to be a universal maintenance item for all manufacturers, much the same as changing the engine oil or any other part of the running gear, you have to wonder how necessary it really is for a street driven car. After all, the liabilities are the same for all manufacturers, and lawyers like to keep ahead of possible legal problems, so you have to assume if changing brake fluid was really a critical maintenance item it would be universally required for all cars.



Every auto maker tells you to change tires when the tread is down to the wear indicators for obvious reasons, it's a universal, no questions asked kind of thing. But, for some manufacturers to have NO requirement to change brake fluid, and others to say it's absolutely necessary every two years has to call into question the true necessity of it as a maintenance item, right??

 

You are missing the point of different types of brake fluid requiring different maintenance.

Most non performance cars use DOT 3 brake fluid, which is less prone to absorbing moisture than DOT 4 fluid used by many performance cars, such as BMW and Porsche. DOT 4 fluid has higher boiling points thus better performance, but it absorbs moisture more easily.

 

I had the brake fluid changed at 19k done by dealer along with 20k service on my 2015 Macan and notice an improved in braking especially the initial bite.

 

Changing the brake fluid gets rid of the acids that eat away inside the slave cylinders. I have been up close and personal with this issue with my Ducati motorcycles. When the bores get eaten up the rubber parts go fast. Every time you run your car the brakes get super hot then get cold after you park. Cycle that thousands of times and the brake fluid goes south. It isn't just moisture.

 

What acid are you referring to? Is brake fluid acidic to begin with? Or perhaps it becomes acidic with use? Never heard of this before.

 

brake fluid flush

How important would you say is the 2 year/20,000 mile brake fluid flush?

For the Macan and Cayenne, is this really a crucial maintenance cycle?

 

IMO changing brake fluid based on testing is far more accurate than just changing it based on a time interval. I’ve had brake fluid that did not need to be changed until it was 5 years old, and I’ve had brake fluid that needed to be changed after only a year.

Not suggesting not to change your fluid when it needs it, but when was the last time you heard of am in warranty brake system repair where it could have had anything to do with not changing brake fluid? This is very rare anymore.

Problems caused by brake fluid not being changed as needed tend to show up way down the road as the car gets much older and almost is always out of warranty.

 

In this day and age, we are still using stone age technology brake fluid. I wonder what's so hard to come up with fluid that does not absorb moisture. It's a simple hydraulic system. Why can't the brakes be adapted to use hydraulic fluid? Then I thought that the brake fluid makers would shoot themselves in the foot if the fluid need not to be changed often. Of course, the service shops will see a big drop is sales also. What a racket!

 

I've long assumed the reason for changing brake fluid on a street vehicle was to protect the system components from deterioration from moisture, such as metallic brake lines. Wrong?

 

Did you read above? 3% moisture in DOT 3 results in 100 degrees lower boiling point. Get on the brakes hard and Pfft ..... it boils away.Now the brake line problems might also be an issue but brake fade would seem to be the big issue. Watch. I'm sure someone will wonder where the videos are of cooked brakes on the street? How many people video record while driving? 3? Unless in Russia :laugh:

987S Cooked braked. Pedal to the floor. I assume he was either accelerating or braking as hard as possible

3:35 Cooked brakes

11:37 cooked brakes.

 

I would never let the dealer get away with the sunroof drain excuse (unless I did not clean the sundrains). If your drains really were cleaned, should be easy to show that clean drains don’t prevent the problem.

I will never ever let a car dealer extort money out of me to insure that a warranty remains valid.

 

I would never let the dealer get away with the sunroof drain excuse (unless I did not clean the sundrains). If your drains really were cleaned, should be easy to show that clean drains don’t prevent the problem.

I will never ever let a car dealer extort money out of me to insure that a warranty remains valid.

Trying to argue with Porsche about what they will pay for and what they will not, is like arguing with the IRS over what you owe in taxes..............or what they say you owe.........its a fight best avoided if at all possible.

They do what they want, sometimes the cost to fight over it out weighs the end result.

If the design sucks, and paying $250/2 years means they have no leg to stand on and nothing to say, then it is what it is, unless I video the procedure and have proof of the VIN and the time/day they can deny warranty for whatever they want for not adhering to a schedule.

Some fights are worth having, some are not, yeah its extortion, but the fact is they stated if we had had the drains cleaned by the dealer they would have ate both modules, now that its been documented, if it leaks again, they agreed to eat the modules under warranty for the next two years.

So I spent $250 to guarantee the repair moving forward.........>

 

Is there a DIY on checking/cleaning these drains ???