First brake flush ever (Unintentional!!!)

[ptschram]

If the manufacturer's maintenance schedule calls for a brake fluid flush at a given mileage and I don't offer it to the client, I'm being negligent as the manufacturer said it needed to be done at that point.

Two of the shops where I worked, one a dealership, flushed the brake fluid every time pads were changed as they opened the bleeder to compress the pistons and it was just as easy to flush it all out at the same time.

I recently avoided an argument with a guy at Napa who claimed he'd never changed the oil in his trucks and ran them for hundreds of thousands of miles. I hope I never buy one of his trucks.

 

[buildmyown]

I can say the only time i flush brake fluid or even a partial flush is when i do pads. Open the bleader compress piston top off as needed. With that said brake lines rot from the outside in new england along with everything else. Perfect example my mother has a 98 camry with 202,000 on it she has owned it since 2000 when she bought it the car had 20,000 on it and it was from FL. The car was always serviced by a Toyota delership till 100K and the warranty ran out. The car has always had all the recomended services done on time including all fluid flushes and that also includeds the brake fluid. thats probally why at 3000 miles the oil still looks new. Now it is serviced by a local indy shop if I dont have the time to do it. Few weeks ago she calls me to tell me it has a soft pedal. Now just a few months ago I put 4 new calipers pads and rotors on it. One caliper was leaking in the front one was frozen in the rear. So for the life of me I couldnt fiqure out why. I go and get the car for a test drive didnt even make it out of the driveway and the pedal hits the floor. Check the master and its empty now thats really odd that me. Fill the master pump the pedal and see it pouring onto the ground. By now its 9PM no way can i get the parts to fix it or do i have the time. I drove the car to the local shop only using the parking brake to stop. Had my mother in front of me in my car so if something did go wrong no harm no foul plus rural area late at night no traffic and only about 5 miles to the shop. I lent her one of my cars while hers was in the shop. I know the owner of the shop and he always saves the old parts for me to see. The reason it lost all the brakes is because the 2 rear lines rotted out and the car has a crossed braking system LF and RR are one system and the RF and LR are the other.

So to make a long story short even by changing the fluid on a regular basis brake lines rot out.

 

[LawnDart79]

I'm not going to argue with you guys, if you feel it's really important to flush your brake fluid, by all means do so. I'm not here to tell you not to do it, I'm just saying it's MY OPINION, repeat MY OPINION, that such a service is generally not necessary on many cars. Whether you agree with my opinion or not is another story.

Now, if your vehicle's maintenance schedule says to do the flush, then I do recommend you do the flush.

Now as far as the "professional mechanic" comment. If we're gonna discuss credentials, I was a "professional mechanic" as you call it, but I worked on the electrical/electronics/engine controls team. I had my head buried in these types of customer concerns all day as opposed to being assigned brake jobs.

Maybe the slugs over on the brakes/maintenance/gravy team saw lots of cases where brake fluid needed to be flushed, I don't know. I do know those guys were best friends with the BG and Wynns snake oil flush chemical salesman, so who knows??? I do know the techs and service writers got a kickback from the flush chemical salesmen for every flush sold to a customer, so lots of flushes of various types got sold.

So, maybe you guys are correct, maybe these flushes are VERY important, but I've never done it on any of my vehicles and I'm still alive to tell about it, believe it or not.

 

[srmofo]

I'm not going to argue with you guys, if you feel it's really important to flush your brake fluid, by all means do so. I'm not here to tell you not to do it, I'm just saying it's MY OPINION, repeat MY OPINION, that such a service is generally not necessary on many cars. Whether you agree with my opinion or not is another story.

Now, if your vehicle's maintenance schedule says to do the flush, then I do recommend you do the flush.

Now as far as the "professional mechanic" comment. If we're gonna discuss credentials, I was a "professional mechanic" as you call it, but I worked on the . I had my head buried in these types of customer concerns all day as opposed to being assigned brake jobs.

Maybe the slugs over on the brakes/maintenance/gravy team saw lots of cases where brake fluid needed to be flushed, I don't know. I do know those guys were best friends with the BG and Wynns snake oil flush chemical salesman, so who knows??? I do know the techs and service writers got a kickback from the flush chemical salesmen for every flush sold to a customer, so lots of flushes of various types got sold.

So, maybe you guys are correct, maybe these flushes are VERY important, but I've never done it on any of my vehicles and I'm still alive to tell about it, believe it or not.

Your opinion is wrong. Simple as that. And if Im reading your comment correctly, you are insinuating that the only reason behind flushing any of the fluids is for a kickback? I just cant for the life figure out why some people are so dead set against it. Every other fluid in the car wears out but for some reason people think brake fluid is magic and never wears or deteriorates.

And about the gravy train comment, I will do anything from change oil to "electrical/electronics/engine controls team" or whatever that **** is you're talking about. I just call myself the lead tech. I find it hard to believe you made it anywhere near diagnosing driveability concerns without first learning how to properly diagnosis brake concerns properly, after all, it is just a gravy train. Everybody was new to the business it some point and the fresh meat gets the easy stuff. Keep throwing jabs at me and Ill keep throwing them back. Im not a kool aid drinker or a gravy grabber, I just like to do the job right which is not usually quicker or cheaper.


Good night guys, Im out before this thing gets locked up

 

[metal1313]

i flush my truck when i do rotors and pads since its cheap and easy.

you can buy a mityvac or similar or build one

http://faculty.ccp.edu/faculty/dreed/campingart/jettatech/bleeder/index.htm

i did and it cost me around 30 total since i bought several master cylinder caps

 

[brslk]

IMHO comparing brake fluid to oil and the changing of said fluids is ridiculous.
The braking system is a closed system. The oil system is not.

If you are getting contaminates in the brake system it is because of a failure somewhere.

If you get contaminates in the oil system it is because the oil system is doing its job.

That is why there are oil filters and not brake fluid filters.

For a so called "Tech" to compare the two makes you sound stupid.

Having said that. If you find your brake fluid contaminated you should first find out how it became contaminated, fix the problem and then flush.

 

[shane3fan]

I dont want to cause an issue with my first post on this forum-but this one is right in my wheel house so to speak.

Ive been in the car business for nearly 20 years and Im not even 36 years old yet.

I will only tell you facts.

Brake fluid systems are not sealed. Check into how the cap vents pressure when the brake pedal is applied and released and then get back to me.

Brake fluid is exposed to very high temps from time to time.

Mercedes Benz--often called the best car in the world--REQUIRES brake fluid flushes once every two years regardless of mileage. If we were to have a car on our showroom that was NEVER driven but sat for two years before we sold it we would HAVE to perform a brake fluid flush before we could deliver it.

 

[PassnThru]

Good night guys, Im out before this thing gets locked up

Now that's funny considering you are the one that derailed the thread with post number 2.

 

[BTC]

I think the rationale behind changing your brake fluid is that the boiling point drops as it absorbs moisture, not to mention that it begins to promote corrosion within the system. It seems to make more sense to change it periodically than to just say f*** it, but to each his own.

 

[bentwrench54]

adding to the fire....

the only time i've flushed brake fluid was when i had to do repairs to the hydraulic system on any of my personal vehicles.

when i replaced the master cylinder and wheel cylinders on my wife's buick this spring.

when i replaced all brake lines and hoses on my 2000 astro 2 years ago this christmas.

when i replaced all brake lines and hoses on my 1995 astro 3 years ago this summer.

when i was younger and worked on my own stuff it didn't seem to be important to me.

now that i work with this stuff daily, i'll pay closer attention to it.

 

[Stick]

IMHO comparing brake fluid to oil and the changing of said fluids is ridiculous. The braking system is a closed system. The oil system is not. If you are getting contaminates in the brake system it is because of a failure somewhere. If you get contaminates in the oil system it is because the oil system is doing its job. That is why there are oil filters and not brake fluid filters.

For a so called "Tech" to compare the two makes you sound stupid.

The only thing that sounds "stupid" is your take on things. I'd wager that a good number of "Techs" both realize and understand that a brake system isn't truly "sealed", and for good reason. Need some evidence?

Behold, a standard brake system cap from a modern vehicle. Nothing special here really, IIRC it's from a 4 channel Bosch or Wabco ABS system.

If we remove the rubber diaphragm it looks like something is going on here. Notice the channel going from the edge of the cap to the center?

Not the greatest picture ever, but if you look carefully at the diaphragm you can see a slit in it. Why's that slit there? It's so the master cylinder can breathe during ABS application (when fluid levels can change), and also to prevent self application of the brakes during temperature changes. It's only a small amount of air that travels back and forth through the slit (or sometimes a pinhole), but over time it's enough to introduce contaminants to the system in the form of water vapor from the ambient air.

This water vapor eventually condenses and settles to the lowest point in the system, which happens to be the calipers, hoses, etc. This is why you can't just take a look at what's in the master cylinder and call it good. To get a true representation of what's going on with your brakes, you need to get a sample of brake fluid from the location where the contaminants are most likely to be. Seeing how you have to open the system to get that sample anyway, why wouldn't you take just a couple minutes more and just do the job properly and remove the old fluid by gravity bleeding it, manually bleeding it, or god forbid... flushing it?

Maybe some of you should read what I posted back in post #32 of this thread. There is a reason brake fluid isn't on a dedicated service schedule, the amount of maintenance required to that system is going to vary just from the use of the vehicle and the climate that it's operated in, but that doesn't mean that it's something that is free from any maintenance concerns. Luckily for us, the engineers have taken the safe route and over-engineered the system so that it can withstand a lack of maintenance from the average vehicle owner.

It used to be that back in the "old days", a proper brake job included rebuilding wheel cylinders, and since the system was completely open, fresh brake fluid was put back in negating the need for a "flush". Now with components lasting longer than ever, maybe we need to pay more attention to what's actually going on with our brakes.

 

[brslk]

The only thing that sounds "stupid" is your take on things. I'd wager that a good number of "Techs" both realize and understand that a brake system isn't truly "sealed", and for good reason. Need some evidence?

Behold, a standard brake system cap from a modern vehicle. Nothing special here really, IIRC it's from a 4 channel Bosch or Wabco ABS system.

If we remove the rubber diaphragm it looks like something is going on here. Notice the channel going from the edge of the cap to the center?

Not the greatest picture ever, but if you look carefully at the diaphragm you can see a slit in it. Why's that slit there? It's so the master cylinder can breathe during ABS application (when fluid levels can change), and also to prevent self application of the brakes during temperature changes. It's only a small amount of air that travels back and forth through the slit (or sometimes a pinhole), but over time it's enough to introduce contaminants to the system in the form of water vapor from the ambient air.

This water vapor eventually condenses and settles to the lowest point in the system, which happens to be the calipers, hoses, etc. This is why you can't just take a look at what's in the master cylinder and call it good. To get a true representation of what's going on with your brakes, you need to get a sample of brake fluid from the location where the contaminants are most likely to be. Seeing how you have to open the system to get that sample anyway, why wouldn't you take just a couple minutes more and just do the job properly and remove the old fluid by gravity bleeding it, manually bleeding it, or god forbid... flushing it?

Maybe some of you should read what I posted back in post #32 of this thread. There is a reason brake fluid isn't on a dedicated service schedule, the amount of maintenance required to that system is going to vary just from the use of the vehicle and the climate that it's operated in, but that doesn't mean that it's something that is free from any maintenance concerns. Luckily for us, the engineers have taken the safe route and over-engineered the system so that it can withstand a lack of maintenance from the average vehicle owner.

It used to be that back in the "old days", a proper brake job included rebuilding wheel cylinders, and since the system was completely open, fresh brake fluid was put back in negating the need for a "flush". Now with components lasting longer than ever, maybe we need to pay more attention to what's actually going on with our brakes.

So the very minor amount of air that CAN contaminate the brake system is comparable to the oil system?

I am very glad you are not the "tech" that works on my car.

I prefer a mechanic. Not a part changer.

 

[ptschram]

So the very minor amount of air that CAN contaminate the brake system is comparable to the oil system?

I am very glad you are not the "tech" that works on my car.

I prefer a mechanic. Not a part changer.

Given the size of the items that are moving into and out of that system every tie the pedal is depressed and released, there could be any of a number of things takingpalce that we don't want to in our brake fluid.

C02 in the atmosphere is dissolving in the hygrocopic brake fluid, acidifying the brake fluid.

Water is similarly entering through that avenue, thus lowering the boiling point of the fluid and increasing its corrosivity even more than the acidic CO2 that's entered.

Let's not forget that there is a good bit of ground-level ozone that is both reacting with the brake fluid, but also deteriorating the seals in the system.

When we are working on atomic and sub-atomic particles, it doesn't take a big hole to cause significant problems. Might not happen today, or tomorrow, butit might happen. It's cheap liability insurance.

 

[WRX/Z28]

So the very minor amount of air that CAN contaminate the brake system is comparable to the oil system?

I am very glad you are not the "tech" that works on my car.

I prefer a mechanic. Not a part changer.

I love that you're calling the guy a parts changer after he showed you that the brake system is not "sealed" as you and many others seem to think. That's ballsy...

Brake fluid is ~$20 for enough to replace everything in your car. Are you guys really that lazy/cheap that you're going to cling to the belief that brake fluid is good for the life of the vehicle?

**** BTW, if you're participating in this thread, why are you using a mechanic at all? If you're throwing your $.02 in, shouldn't that mean you at least work on your car yourself?

 

[MrMark]

Stick, I have that same chair. It is my favorite.

You parts changer!

The Germans all require flushes. I think a lot of this is that most of the piles people drive it doesn't matter if a little moisture is in there. These cars don't perform well enough braking wise for anyone to notice a little decreased performance. I doubt anyone is going to notice that a Chevy Tahoe, for example, takes a little longer to stop.

I wonder if air can get in the system through the seals in other places too. Air is able to move through a tire at a molecular level so I am guessing it can get into the brake system in places in addition to the vented cap.

 

[WRX/Z28]

Now that's funny considering you are the one that derailed the thread with post number 2.

Seems like we're on topic to me...

"First brake flush ever (Unintentional!!!)" was the thread title, right?

 

[Stick]

So the very minor amount of air that CAN contaminate the brake system is comparable to the oil system?

Obviously you haven't been paying attention. In no way did I compare the two, I've only stated that it's on a "periodic maintenance" interval for some vehicles and that how often it needs to be changed depends entirely on driving style and climate among other factors. Brake fluid is not and never has been a "lifetime fluid" and talking to brake systems manufacturers (like Bendix) will confirm that. It's just fortunate that most engineers have the foresight to design a system that handles the kind of abuse it does.

I am very glad you are not the "tech" that works on my car.

I prefer a mechanic. Not a part changer.

If you only had any idea... You might want to do a little more reading about me. I don't work on private vehicles and make money from selling un-needed fluid flushes hand hanging parts. I'm the farthest thing from a parts changer you'll ever find.

 

[metalhead212121]

I prefer a mechanic. Not a part changer.

Rarely do I call anyone out over the net but you do realize that Stick goes out of his way to do monthy tech threads??? If he's a parts changer I'd LOVE to see what a mechanic could write up for monthly sticky threads.


http://www.garagejournal.com/forum/showthread.php?t=111779


http://www.garagejournal.com/forum/showthread.php?t=102616

Dan

 

[bgott]

I prefer a mechanic. Not a part changer.

I usually hear that **** out of people that are too cheap, and too ignorant, to properly repair or maintain their vehicles. What is being implied is that, if you are a *real* mechanic, it wouldn't cost him anything to keep his POS running. Hell, all a *real* mechanic needs to diagnose and repair a modern fuel injected vehicle is a paper clip, you don't need all those expensive scan tools and meters!

 

[W650Mike]

I'm glad that Stick joined this thread.

To the OP: Good job on the brake job (and flush). Rust ***** and my projects always mushroom - both in time and $$!

PS: I'm a flusher and damn proud of it!!

 

[scott37300]

So the very minor amount of air that CAN contaminate the brake system is comparable to the oil system?

I am very glad you are not the "tech" that works on my car.

I prefer a mechanic. Not a part changer.

To those of us that have been on this forum for a little while you are really sounding like an idiot. To attack someone that if you read his posts clearly knows what he is talking about and has a thousands times better credability than you on this forum just shows the lack of your intelligence. Stick is the farthest thing from a parts changer and has wrote many great posts on testing things out before throwing parts at the problem. If you prefere a mechanic than by all means take your car to one, but most on this forum do their own maintenance or are prefessionals.

As for brake fluid flushes I will add my thoughts. I am of the mind that it deffinately can't hurt to put some clean fresh fluid in the lines. I started doing this a couple years ago because a lot of the manufacturers are recomending it every 30K now. If some manufacturers recomend it then there is a reason they are, but if it's good enough for one vehicle than it's good enough for all of mine. I bought a mityvac and it takes me about half hour while taking my time and a few bucks for fluid.

I have done about 12 vehicles now and everyone of them came out black or green. Did a Honda with 30K on it that was dirty, did a 04 impala with 45K on it that was blackish/green, an 09 malibu with 50K that was very dirty, 00 taurus that was just nasty. The point is that EVERY vehicle that I changed the fluid out of was discolored and had particles in the dirty fluid, EVERY vehicle.

In my opinion there is no reason other than being lazy that one wouldn't want to change out one of the most important fluids in the vehicle for safety.

If some of you guys don't want to change your fluid that is fine and it's your vehicle. But when something that can mean the difference between stopping and not stopping and is cheaper than doing an oil change and takes about the same time as an oil change I see no reason why someone would ignore it.

 

[esmith2039]

I do regular flushes every 30k or 2 years on the Escape a bit longer on the cars. I get scoffed at but regular flushes on the Escape really pays off. We got it 32k and by 40k I starting to get some pulsation. On a whim decided to try a flush instead of changing the brakes out. Escapes are known to eat brakes. The rear cylinders were full of junk the front were fine. The pulsation went away and never had a problem since. The only thing I could figure is the front brakes were doing all the work and overheating. The brakes themselves lasted to 100k and could of lasted longer if I would took them apart and greased them a few times. Still have the original cylinders on the back so don't know how anything got in there. Truthfully that is the only vehicle where I actually felt a difference after a flush.

 

[99LeCouch]

The Honda in the house calls for brake fluid flushes every 2 years. Just did it, and got rid of a hard to modulate brake pedal. It used a can of Honda Genuine brake fluid to do all the lines. Couldn't tell a difference between new and old fluid except by the car's behavior.

My Buick with 6 month old brake fluid and new lines all around has dark brake fluid. I'm not worried since it was just done.

 

[shane3fan]

one other thing about Mercedes and brake fluid ; If Mercedes was doing brake flushes just as a way to increase profit, would they pay for the flushes? If your car was under warranty when Benz had the maintenance included with vehicle purchase they replaced the brake fluid every 2yrs or 20k. Pre paid maintenance that they have now also includes brake flushes. Mercedes also reserves the right to void any ABS warranty if a failure is proved to be due to no brake fluid flush. That tells me that they firmly believe that brake flushes are necessary.

Maintenance for anything can be seen as a waste of money. You could drive your car for 30k miles or more without changing the oil/filter, 80k or so without air filters, maybe forever without trans,diff , power steering or brake fluid----but they are all good, sound measures to take to make sure the car lasts as long as possible. And isnt that the entire point of maintenance to begin with?

 

[Lotek]

I see we have another convocation of the church of the brake fluid inviolate.

No point in arguing with them, they believe.

If the label on the can warning that it absorbs moisture, mfg recommendations, and the advice of experienced techs isn't enough, I don't know what is.

I know they stand behind their beliefs...I wouldn't stand in front though.

 

[brslk]

To those of us that have been on this forum for a little while you are really sounding like an idiot. To attack someone that if you read his posts clearly knows what he is talking about and has a thousands times better credability than you on this forum just shows the lack of your intelligence. Stick is the farthest thing from a parts changer and has wrote many great posts on testing things out before throwing parts at the problem. If you prefere a mechanic than by all means take your car to one, but most on this forum do their own maintenance or are prefessionals.

As for brake fluid flushes I will add my thoughts. I am of the mind that it deffinately can't hurt to put some clean fresh fluid in the lines. I started doing this a couple years ago because a lot of the manufacturers are recomending it every 30K now. If some manufacturers recomend it then there is a reason they are, but if it's good enough for one vehicle than it's good enough for all of mine. I bought a mityvac and it takes me about half hour while taking my time and a few bucks for fluid.

I have done about 12 vehicles now and everyone of them came out black or green. Did a Honda with 30K on it that was dirty, did a 04 impala with 45K on it that was blackish/green, an 09 malibu with 50K that was very dirty, 00 taurus that was just nasty. The point is that EVERY vehicle that I changed the fluid out of was discolored and had particles in the dirty fluid, EVERY vehicle.

In my opinion there is no reason other than being lazy that one wouldn't want to change out one of the most important fluids in the vehicle for safety.

If some of you guys don't want to change your fluid that is fine and it's your vehicle. But when something that can mean the difference between stopping and not stopping and is cheaper than doing an oil change and takes about the same time as an oil change I see no reason why someone would ignore it.

I really should attach one of those devices that you have to blow into before you can start your car to my keyboard.

It seems after having a few too many wobbley pops I put my foot in my mouth and my head up my ****.

I sincerely apologize to anyone I insulted but most especially to stick.
I have taken the time to read a lot of his very helpful and knowledgeable
posts and see that he clearly knows of what he speaks.

No more drunk posting for me. I am not a big drinker and when I do drink I am clearly not a big thinker.

Bruce.

 

[justanengineer]

Yup, this thread ballooned rather unexpectedly while Ive been busy elsewhere. I apologize if Im a bit late to this rodeo, but Ive been rather blind lately (almost literally).

I can guarantee that your 12 year old 130k mile brake fluid is NOT the same as new. How did he (the "tech") compare new to old?

Brake fluids absorb water by design......Please do yourself, and the others around you a favor, and read up on brake fluid.

What kind of engineer are you btw?

Im a mechanical engineer making his living in engine design for one of the worldest largest manufacturers. If I told you who I work for (I wont on the net for professional/personal reasons), the majority on this forum would agree our lab is THE place to have an analysis like this completed as its one of the world's oldest and most respected fluid analysis labs.

The fluid in question was analyzed for % water content, color, clarity, lubricity, density, impurities/pollutants, and a host of other characteristics. Im not a chemist nor do I pretend to be, but when the lab says every single one of these characteristics in both samples are within a reasonable tolerance of each other, and well within the SAE standards for new fluid, I tend to believe them.

I really see no reason why everyone gets so worked up about this. Brake fluid is simply a check to some manufacturers, no more important than checking bushings or bearings. Yes, nasty fluid does exist in quite a few vehicles. But if the fluid passes a quick visual test and the brake pedal feels fine, I see no reason to worry about changing it. Growing up in the worst of the rust belt, IMHO there are much more important brake system services, such as greasing the caliper slide pins. Ive never heard of a vehicle crash due to nasty fluid, but Ive seen quite a few calipers lock up and cause crashes because they werent serviced properly. Ive also seen quite a few wheel bearing failures. How many of you preaching about brake fluid actually remember to check wheel bearings? Failure to do that simple check could actually get someone killed rather easily when a wheel falls off. At least with brake failures I have a mechanical (parking) brake and a transmission to use.

 

[Lotek]

Given that most of us don't have access to a fully equipped test lab, and that one truck doesn't a representative sample make, and given the dirty fluid that I see on a daily basis, wouldn't it make more sense to run a ten dollar can of fluid through the system every couple of years? And hey, why not check the bearings, pads and calipers while the wheels are off?
Have you ever tried to stop a truck from speed with the parking brake? I have, even with a manual trans, it took a looong time on a downhill, with modern automatics that won't even let you downshift until you are within a certain speed range, not so much. How much is your life, and that of everyone around you worth?

 

[Stick]

I really see no reason why everyone gets so worked up about this. Brake fluid is simply a check to some manufacturers, no more important than checking bushings or bearings. Yes, nasty fluid does exist in quite a few vehicles. But if the fluid passes a quick visual test and the brake pedal feels fine, I see no reason to worry about changing it. Growing up in the worst of the rust belt, IMHO there are much more important brake system services, such as greasing the caliper slide pins. Ive never heard of a vehicle crash due to nasty fluid, but Ive seen quite a few calipers lock up and cause crashes because they werent serviced properly. Ive also seen quite a few wheel bearing failures. How many of you preaching about brake fluid actually remember to check wheel bearings? Failure to do that simple check could actually get someone killed rather easily when a wheel falls off. At least with brake failures I have a mechanical (parking) brake and a transmission to use.

I see what you are saying, I think we're mostly on the same page, and I believe that if your test lab (big yellow iron with a locomotive powerplant facility in Indiana?) says the fluid is within tolerances then it's probably good. However one test result doesn't generate enough confidence for me to say that *all* vehicles are good to go with fluid that old. One thing to keep in mind is that the plural of anecdote is not "fact".

Maybe it's the type of vehicles that I see (emergency service) and the type of use that they are put under that skew my viewpoint on the matter slightly. For my fleet, it makes sense to have a complete brake system flush on a regular schedule, where for your personal vehicle it's probably not an issue. The vehicles I work on see complete brake jobs on the average of every 10-16 months or 8-12k miles or so. I'd probably say that 90% of brake related complaints such as pedal feel/pedal height, brake fade, etc. that aren't a problem with the brake system fundamentals are solved with fresh brake fluid.

I think the best practice is somewhere in the middle ground, there isn't a need for most people to go with a regularly scheduled service, but if you're already doing brake or wheel work of some sort it's not a bad idea to go ahead and flush the fluid while you're there. For whatever it's worth, my personal vehicles are done every 3-4 years or so, and usually when I'm doing other work in the general area.

One of my big pet-peeves in my shop is seeing guys push calipers back in without opening the bleeders. Why pass up a chance to get good clean fluid back into the calipers, even if you aren't going to do a complete system bleed? In fact, Bendix even has a document about "A Good Minimum Brake Job", that outlines pretty clearly the need for fresh, clean fluid. Note that they talk about not forcing fluid back into the system by opening up the bleeders, and further instruct to bleed the system according to manufacturer's guidelines. To me, it just makes sense to do a complete service instead of a half-assed brake job that might return in 3-5k miles with another complaint.

 

[justanengineer]

Stick - Very well stated, and yes we are in agreement. Your bolded statement above is the happy medium I was looking for, and definitely good advice. My truck definitely isnt a fleet, nor even a good representation, so point well taken. Mine was simply that it is possible for fluid to last that long, and there are other services and checks that to me are more critical which are often overlooked even by "professionals" and more so by hobbyists. If I see the need, I definitely will flush the system, but if not, I dont see a need to change the fluid. If youre ever in my neck of the woods get in touch and I will arrange a tour or two if youre interested.

 

[WRX/Z28]

Ive never heard of a vehicle crash due to nasty fluid, but Ive seen quite a few calipers lock up and cause crashes because they werent serviced properly.

I'm betting that crashes that are due to weaker than normal braking, faded brakes, and pulsating pedals are often attributed to driver error.

Ive also seen quite a few wheel bearing failures. How many of you preaching about brake fluid actually remember to check wheel bearings? Failure to do that simple check could actually get someone killed rather easily when a wheel falls off. At least with brake failures I have a mechanical (parking) brake and a transmission to use.

How could a failed wheel bearing cause the wheel to come off? I'm trying to think of a car with a design where a failed wheel bearing could cause this, and i'm coming up with none...

 

[Lotek]

I'm betting that crashes that are due to weaker than normal braking, faded brakes, and pulsating pedals are often attributed to driver error.



How could a failed wheel bearing cause the wheel to come off? I'm trying to think of a car with a design where a failed wheel bearing could cause this, and i'm coming up with none...

I've seen it a couple of times, usually on lifted trucks with oversize tires, seen a couple come in with very loose bearings, one guy thought we were trying to scare him into unnecessary repairs until I shook the wheel. This was a sealed bearing/hub assembly.

I recommend flushes based on visual inspection, if someone asks, I tell them that most mfgs recommend a two year interval, I did my truck after 3 years while I was changing all the other fluids at 60k. The 912 gets it after a track session.

It's preventative maintenance, you do it before there is a problem...

 

[tcianci]

Maybe the Mods need to amend the posting rules to include "No brake flushing posts" as well as no politics or religeon