# Do you really need to change your brake fluid????



## SergioK (Aug 14, 2002)

car_for_mom said:


> Again, bimmerfest.com is the *best!* (I would have said "da bomb", but I wouldn't want anyone from Homeland Security to contact the moderators  :rofl: :rofl: :rofl:


 :bustingup :bustingup :bustingup


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## rruiter (Feb 10, 2004)

wavewuver said:


> Bimmer owners seem preoccupied with changing fluids I've never changed in my 40 years of owning a car. For example, brake fluid. Can anyone tell me why you really need to change your brake fluid every couple of years? I don't take my car to the track.


well, others said it mostly. You also keep better brake performance. The more water in the system, the worse the brake pedal feel gets.
Worst part is the damage to the brake system. Brake fluid is cheap, it's fairly easy to replace and brake components are expensive. Seems like an easy decision to me !


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## The Roadstergal (Sep 7, 2002)

car_for_mom said:


> Soooooo, I hope to show up with turkey baster, brake fluid (oh, defnintely *not* from Savage (or even Crevier; maybe Bavarian Autosport [hopefully that's *all* I'll buy  ) and one Karl Bimmer!


Get ATE Superblue from Eurasian (EAP4parts.com). 



Kaz said:


> Do NOT use silicon (DOT5) brake fluid in vehicles not made for it. It may cause seals to swell, and IIRC it's also not ABS compatible.


To further confuse the issue, DOT 5.1 isn't silicone.


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## Kaz (Dec 21, 2001)

The Roadstergal said:


> To further confuse the issue, DOT 5.1 isn't silicone.


IIRC '5.1' isn't even an actual DOT spec. It's a marketing term for DOT3/4 with higher boiling points.


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## mrtm2008 (Oct 24, 2003)

After reading the previous posts, I have to say for the most part, that many of you are correct. I am a Mechanical Engineer & am currently attending UTI, an automotive technical school. The school has a manufactur's programs with BMW, Volvo, Audi, MB & some others. I will add to the already right answer of, YES, you should change your brake fluid every 2 years & also try to further explain some of the other questions with braking systems, especially BMW.

First off, YES, you "Should" change your brake fluid every 2 years or so. Why??? 

1. Because if only costs about $3.00-$5.00 in Oil (& yes that's after you buy some of the other brake bleeding equipment).

2. As mentioned before, brake fluid will absorb moisture at a rate of about 3% year. It will do so no matter how air tight you think your braking system is. It does not matter if you race your car or not! Especially, if you race, your brake fluid should be changed as frequent as every 3rd race.

DOT ratings are based on the boiling points of the brake fluid. DOT 3 is the most readily used. DOT 5 as mentioned before, has a higher boiling point & as mentioned before is silicon based & will cause rubber seals to swell up & fail. You can ONLY use DOT 3 with DOT 3 brake systems, though you can use DOT 3 in DOT 5 systems...but NEVER the other way around!

To further explain how this moisture effects the boiling point of the brake fluid & effects corrosion of the braking system...As mentioned before, the more moisture in you have in your brake fluid, the lower the boiling point is effected in the brake fluid. You also need to understand that Brake fluid is more than a means to hydraulically push your caliper pistons to stop you. Brake fluid also lubricates the braking system..meaning, the more moisure you have in your brake system, the less the brake fluid acts as a lubricant. This will cause those parts that need lubricated to heat up sooner & will start to have more water flowing over them. Also, you won't be able to see this corrosion with the naked eye, unless, like mentioned before, it's too late & your buying a whole new braking system.



Also to answer some of the other questions about why BMW changes the rotors & brake pads at the same time...

BMW like other manufactures have designed their braking systems based on economics. It is more cost effective for them to just replace rotors than spend the time & $$$ to turn down brake rotors. Most people are unaware of this, but unless your racing, regular, unslotted or cross-drilled brakes will work perfectly fine on all our vehicles. The cost of rotors is about less then $20 if not lower. I had one instructor who writes for a technical journal & flat out asked one brake manufacturer on thier opinion of the different types of rotors and what was recommended. He was told that they charged only $12 for thier plain rotors. Then the same plain rotors that got only crossed-drilled by a machine that cost them about $2/piece, they charged $45/ea for. & then those same plain rotors that also got slotted, they charged about $75/ea. They told him that plain rotors are designed to disipate (sp) as much heat as needed for any day to day application. But it's supply & demand. The main reason they did that, was because people are willing to buy them for that much because of the "Look" they gave their cars & trucks.

Where I was going with that, is that it is so cheap for BMW to just throw away good rotors, is because it's cheaper for them, especially when they are doing the service under warranty. Also, in this day & age of liability, they'd rather replace something that costs that cheap with a new component in case there might be a failure.

Bleeding the brakes means that you are only getting the air out of the brake lines & system.

Flushing the brakes means that you are replacing all of the fluid in the brake system with new brake fluid, in which you do bleed the brakes too.

Also, in regards to the aprehension to the Manufacurer's recommended fluid changes, remember that they are based on progressive advances in fluid modifiers & additives, but most of all, from manufacturers moving toward warranty work (cost out of thier pocket). I would still highly recommend you change the oil on a brand new car after 3000 miles. Also either just change the oil filter, which is a synch on BMWs, every 3000-6000 miles. Though they say that it doesn't need changed until 12,000 miles...new engines still deposite metal filings during the brake in period of the engine.


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## Nick325xiT 5spd (Dec 24, 2001)

The Roadstergal said:


> Get ATE Superblue from Eurasian (EAP4parts.com).
> 
> To further confuse the issue, DOT 5.1 isn't silicone.


 No!

Superblue is crap!

Get ATE Typ200 and avoid staining your brake components for all eternity. You get the exact same (mediocre) performance from Typ200 as you do from SuperBlue. Although the truth is that infrequent changers may want to consider something else. In my experience, Castrol GT LMA lasts a lot longer on the street than Superblue. And it's 1/4th of the price. Not suitable for the track, mind you.


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## Kaz (Dec 21, 2001)

Nick325xiT 5spd said:


> No!
> 
> Superblue is crap!
> 
> Get ATE Typ200 and avoid staining your brake components for all eternity. You get the exact same (mediocre) performance from Typ200 as you do from SuperBlue. Although the truth is that infrequent changers may want to consider something else. In my experience, Castrol GT LMA lasts a lot longer on the street than Superblue. And it's 1/4th of the price. Not suitable for the track, mind you.


I dunno that Typ200 would fare worse than ATE SL or LMA for street use. There are definitely fluids that won't last as long (Motul 600) and that probably aren't great for street use and infrequent changes.

I'm definitely not a fan of the blue tinting, though.


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## Nick325xiT 5spd (Dec 24, 2001)

Typ200 is no worse than Superblue given that they're exactly the same, other than the color.


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## The Roadstergal (Sep 7, 2002)

First I've heard of Superblue staining... it'll give your tubing a blue tinge, but that's all it's done for me.

Ja, Typ 200 is the same stuff. I alternate.


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## kurichan (May 1, 2004)

Donnalee said:


> You dont have to.
> But one day you will be going down the highway and have to hit your brakes hard, your foot will go to the floor and the car wont stop, and bang youre probably dead.
> 
> Brakefluid sucks up water like crazy , through your brakelines and calipers. Water is compressable, so when you press the brake it just compresses the water instead of moving the brake piston. It also makes the fluid boil at a lower temperature creating air pockets which are even more compressable.


While the opening statement above is exaggerated, it's more likely you'll notice your brake pedal soften and notice brake feel degragation and perhaps even less stopping power (perceived, probably not actual). A total loss of braking power is very unlikely. I'm pretty sure you can get away with NEVER changing the brake fluid and be fine.


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## Chris90 (Apr 7, 2003)

kurichan said:


> While the opening statement above is exaggerated, it's more likely you'll notice your brake pedal soften and notice brake feel degragation and perhaps even less stopping power (perceived, probably not actual). A total loss of braking power is very unlikely. I'm pretty sure you can get away with NEVER changing the brake fluid and be fine.


On the plus side, a soft brake makes it easier to heel & toe - after I get a fluid flush, I have trouble heel & toeing.


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## rruiter (Feb 10, 2004)

kurichan said:


> While the opening statement above is exaggerated, it's more likely you'll notice your brake pedal soften and notice brake feel degragation and perhaps even less stopping power (perceived, probably not actual). A total loss of braking power is very unlikely. I'm pretty sure you can get away with NEVER changing the brake fluid and be fine.


OH you will know before it is too late. However you won't be "fine" wrt the condition of your braking system. The corrosion will eat up the expensive parts and your wallet won't be "fine"


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## rruiter (Feb 10, 2004)

mrtm2004 said:


> After reading the previous posts, I have to say for the most part, that many of you are correct. I am a Mechanical Engineer & am currently attending UTI, an automotive technical school. The school has a manufactur's programs with BMW, Volvo, Audi, MB & some others. I will add to the already right answer of, YES, you should change your brake fluid every 2 years & also try to further explain some of the other questions with braking systems, especially BMW.
> 
> First off, YES, you "Should" change your brake fluid every 2 years or so. Why???
> 
> ...


Good info, I am missing where DOT 4 comes in and what's compatible with it.


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## Nick325xiT 5spd (Dec 24, 2001)

rruiter said:


> Good info, I am missing where DOT 4 comes in and what's compatible with it.


 DOT 4 is what you use in BMWs. Don't use anything else.


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## Chris90 (Apr 7, 2003)

Nick325xiT 5spd said:


> DOT 4 is what you use in BMWs. Don't use anything else.


I'm confused, you saying ATE Blue and the brown version are both going to blow the seals on a BMW? What about the Motul 600 stuff?


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## Nick325xiT 5spd (Dec 24, 2001)

Dawg90 said:


> I'm confused, you saying ATE Blue and the brown version are both going to blow the seals on a BMW? What about the Motul 600 stuff?


 Huh?

They are DOT 4 fluids.


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## Nick325xiT 5spd (Dec 24, 2001)

That said, so far as I can tell, DOT 3 and DOT 4 are compatible. (At least that's my assumption when certain fluids are listed as exceeding both standards.) You just shouldn't use DOT 3 because it's inferior, unlike DOT 5, which is just not compatible.


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## SergioK (Aug 14, 2002)

Nick325xiT 5spd said:


> No!
> 
> Superblue is crap!


  :tsk: :loco:

I've been using it for years now and I definitely do NOT think it's crap.


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## Nick325xiT 5spd (Dec 24, 2001)

SergioK said:


> :tsk: :loco:
> 
> I've been using it for years now and I definitely do NOT think it's crap.


 Well, if you don't mind staining your brakes permanently, it's just fine.

And if you're under warranty, an unfriendly dealer CAN use SuperBlue to get your brake warranty voided. So no one under warranty should use superblue, and anyone out should think about whether or not they like having lots of blue components before they use it.


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## SergioK (Aug 14, 2002)

Nick325xiT 5spd said:


> Well, if you don't mind staining your brakes permanently, it's just fine.
> 
> And if you're under warranty, an unfriendly dealer CAN use SuperBlue to get your brake warranty voided. So no one under warranty should use superblue, and anyone out should think about whether or not they like having lots of blue components before they use it.


The last thing I'm thinking about coming into a braking zone is the color of my brake fluid reservoir. :tsk:


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## operknockity (Apr 19, 2002)

doeboy said:


> I think he means "what do you mean you don't know anyone who alternates between Typ200 and SB.... " because I think most of us SCTS guys do...


Really :dunno:

I haven't seen every fluid flush you guys have done, but all the ones I have seen have been done with SB, though I haven't noticed the color of the old fluid.

(Or maybe I really am :loco: )


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## doeboy (Sep 20, 2002)

operknockity said:


> Really :dunno:
> 
> I haven't seen every fluid flush you guys have done, but all the ones I have seen have been done with SB, though I haven't noticed the color of the old fluid.
> 
> (Or maybe I really am :loco: )


I think you just missed a lot of our in-between mini-tech sessions where these things happened. 

the :loco: part could be true too... after all... you do hang out with us sometimes...  uch:


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## operknockity (Apr 19, 2002)

doeboy said:


> I think you just missed a lot of our in-between mini-tech sessions where these things happened.


Quite true. I've also come fairly late to the last few regular tech sessions at B&M and I know some fluid flushes occured those days before I got there.


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## car_for_mom (Jul 15, 2002)

Just ordered Typ200 (Gold) from Bavauto...there's a little sale on right now, so it was $10.95 for a liter.

Sooooo....yet another _neue_ Bimmer experience ahead (changing the oil, driving the track at California Speedway during Oktoberfest2004, changing brake fluid, getting Dr. Panke to remove I-Drive from future Bimmers :angel:   )


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