# Which brake fluid to use.



## oaksenov (Jul 2, 2003)

I am confused. I have called my local BMW dealer at Sterling, VA to ask if they sell DOT 4 brake fluid for 2003 525i. The guy said that they sell it and it is actually DOT 5 fluid now. BUT the manual for the car sais it is DOT 4 fluid. And from what I read so far DOT 5 does not mix well with DOT 4 fluid. 
Could someone clarify this for me?


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## Nick325xiT 5spd (Dec 24, 2001)

I've read the same things you've read... And that DOT 5 brake fluid shouldn't be used in systems that might have any water in them as it tends to pool in bad places.

Just get some ATE Typ 200 from OG Racing in Manassas. It's a similar color to the BMW fluid so you can avoid warranty issues, but it's more tolerant of higher temperatures.


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## oaksenov (Jul 2, 2003)

The other thing I have heard that it is HUGE NO NO to put DOT 4 after DOT 5 was in the system. And now since the guy said that it is DOT 5 for my car I am really not sure what to do. 
I wanted to bleed the clutch only. And now it looks like I have to bleed brakes as well. :-(


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## DZeckhausen (Mar 11, 2003)

oaksenov said:


> The other thing I have heard that it is HUGE NO NO to put DOT 4 after DOT 5 was in the system. And now since the guy said that it is DOT 5 for my car I am really not sure what to do.
> I wanted to bleed the clutch only. And now it looks like I have to bleed brakes as well. :-(


The guy who you spoke with is totally wrong if he said to use DOT 5! That silicone-based fluid is completely inappropriate for use in a car with ABS and, even if you could use it, it would give you a spongy pedal feel because it is slightly compressible.

On the other hand, he might have been talking about "DOT 5.1" fluid which is rather unfortunately named, because it has nothing to do with DOT 5. It is compatible with DOT 4 and is a lower viscosity. Perhaps that is what he was talking about. I certainly hope so.

In any case, you would do well to follow Nick325xiT 5spd's advice and use ATE TYP 200 or ATE Super Blue Racing. You could also pick up some BMW DOT 4 fluid (or DOT 5.1) at the dealership, but it would probably be more expensive than the ATE fluid.


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## DSPTurtle (Oct 4, 2003)

ATE Superblue all the way!!! Plus it is a cool color...Bling Bling. Makes it easy to see when you have all the old fluid drained out. ATE has blue and gold so you just change every two years between colors to make sure you know when it has all been drained out.
JB


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## DZeckhausen (Mar 11, 2003)

Given that your car is a 2003 model 525i 5-speed, I'm going to assume that the only reason you want to bleed the clutch is in order to do the CDV delete modification. Otherwise, the dealer should be doing brake fluid swaps for the next few years under the free maintenence plan.


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## mottati (Apr 15, 2003)

DSPTurtle said:


> ATE Superblue all the way!!! Plus it is a cool color...Bling Bling. Makes it easy to see when you have all the old fluid drained out. ATE has blue and gold so you just change every two years between colors to make sure you know when it has all been drained out.
> JB


If you are underwarranty, you may want to stick with the ate type 200, as the blue fluid seems to be a signal for bmw techs to freak out. I had a guy write a paragraph on my repair order saying how i no longer have warranty coverage for using a "non approved silicone" brake fluid. I argued for a while, but finally just brought the can to show them ate is dot 4, not silicone... Additionally, that stuff stains everything blue, your master cylinder, bleeder, etc. I do agree it's good stuff though...
Mike


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## DZeckhausen (Mar 11, 2003)

mottati said:


> If you are underwarranty, you may want to stick with the ate type 200, as the blue fluid seems to be a signal for bmw techs to freak out. I had a guy write a paragraph on my repair order saying how i no longer have warranty coverage for using a "non approved silicone" brake fluid. I argued for a while, but finally just brought the can to show them ate is dot 4, not silicone... Additionally, that stuff stains everything blue, your master cylinder, bleeder, etc. I do agree it's good stuff though...
> Mike


Agreed! TYP 200 may be not quite as cool a name as "Super Blue Racing" but it's just as good and it is DOT compliant. The Super Blue won't meet the DOT 4 specification because of its color. Believe it or not, part of the DOT 4 spec calls for "clear to amber" color. So ATE Super Blue meets all the DOT 4 performance specifications, but it can't call itself a DOT 4 fluid because it is blue.

I've seen several cars with reservoirs stained dark blue, such that you can't tell the fluid level without removing the cap. It took several years of use, but it does happen.


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## possessed007 (May 26, 2003)

DZeckhausen said:


> Agreed! TYP 200 may be not quite as cool a name as "Super Blue Racing" but it's just as good and it is DOT compliant. The Super Blue won't meet the DOT 4 specification because of its color. Believe it or not, part of the DOT 4 spec calls for "clear to amber" color. So ATE Super Blue meets all the DOT 4 performance specifications, but it can't call itself a DOT 4 fluid because it is blue.
> 
> I've seen several cars with reservoirs stained dark blue, such that you can't tell the fluid level without removing the cap. It took several years of use, but it does happen.


Yo Dave do you sell any of these fluids?


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## DZeckhausen (Mar 11, 2003)

possessed007 said:


> Yo Dave do you sell any of these fluids?


Not yet. I carry Motul 600, but if you don't race, it would be silly to use this. It's more than twice the price of ATE TYP 200 and, if you aren't boiling your fluid, it gives you no additional benefit. It's really for folks who track in the advanced and instructor level run groups, especially those who use R-compound tires.

For ATE fluids, try http://www.raceshopper.com/ate_brake_fluid.shtml for good pricing. At the moment, that's where I get this fluid for my own street cars and for bleeding customers' brakes.


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## TeamM3 (Dec 24, 2002)

tried them all, switched to Castrol SRF and never looked back ... :eeps: 

wouldn't recommend it for general use though


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## oaksenov (Jul 2, 2003)

I actually came to that dealership Friday night. And obviously some other guy told me that they do not sell DOT 4 fluid. Now I wonder who was that genius I have talked over the phone with. 
So I just went to Curry's Auto and picked up couple of cans with ATE Type 200 just in case. The guy there said that ATE do not make Super Blue anymore, but he can still find it if I wanted. 

Anyway I have replaced CDV today and I have to admit it was the best and quickest mod I have ever done.


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## DZeckhausen (Mar 11, 2003)

TeamZ4 said:


> tried them all, switched to Castrol SRF and never looked back ... :eeps:
> 
> wouldn't recommend it for general use though


Were you still boiling brake fluid when you tried Motul 600? What made you switch to SRF?


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## bluer1 (May 30, 2002)

TeamZ4 said:


> tried them all, switched to Castrol SRF and never looked back ... :eeps:
> 
> wouldn't recommend it for general use though


You must be rich! I've been using Motul longer than I can remember.
:thumbup:


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## DZeckhausen (Mar 11, 2003)

bluer1 said:


> You must be rich! I've been using Motul longer than I can remember.
> :thumbup:


I agree! SRF costs six to eight times more than ATE TYP 200. The best price I've seen is here: http://www.raceshopper.com/castrol_srf_brake_fluid.shtml at $65/liter.

If you are making it through a track event with ATE TYP 200 and NOT getting a soft pedal, then you don't need to pay twice as much for the Motul 600 and you certainly don't need to pay six times as much for the Castrol SRF.

The really interesting thing about SRF is that it has a very high wet boiling point of 518 degrees F, whereas Motul 600 is only 421 degrees F. However, Motul 600 has a higher dry boiling point of 594 F vs SRF which is 590. So, fresh Motul 600 actually has a higher boiling point (by 4 degrees) than fresh Castrol SRF. It's only after sitting in your car for a month or more that the SRF boils at a higher temperature. Motul's boiling point falls away faster with age than SRF and Motul bottoms out almost 100 degrees lower!

For comparison, ATE Super Blue Racing and TYP 200 have a dry boiling point of 536 degrees F and a wet boiling point of 396 degrees F.


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## TeamM3 (Dec 24, 2002)

two reasons; the high wet boiling point means I don't have to be overly concerned about moisture contamination over time and IMO I get a firmer pedal and better control at the limit using it. Yes, it is expensive but 1L thoroughly flushes the entire system and except for an occasional front caliper bleed that doesn't require much add'l filling it is pretty much hands-off. Otherwise, I just do a complete flush on an annual basis. So while $65/L seems relatively expensive it's not really a continuous cost and for the added protection relative to the risk IMO it's worth it. Let's face it, most of you blow that or more on many other things of minor benefit or value. With the other fluids you better be flushing out the entire system on a regular basis to ensure you are getting the high temp protection. It's not much of an advantage on a vehicle that is only used for the street, that is why I don't recommend it for general use.

BTW, for a dry boiling point difference of 4 degF you'd have to be pretty damn lucky for that to be the deciding factor between boiling and not boiling and except for extreme racing brake pads or moisture in the system it's usually the pad that gives up before a quality high temp fluid. Also, if you evaluate the dry vs wet range between the fluids it isn't going to take much moisture absorption before the other fluids are dropping below the boiling point of SRF at the same moisture level, but that precludes the fact that SRF is more moisture resistant than the other high-temp fluids. So again, if you are into maintenance and doing a complete flush before every high temp excursion you can get by with the cheaper fluids.

Finally, I'm not advocating anyone else doing the same. I'm only said, "... *I* switched to Castrol SRF and never looked back". I like it, it works for me and IMO the added cost isn't significant; end of story.


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## DZeckhausen (Mar 11, 2003)

TeamZ4 said:


> two reasons; the high wet boiling point means I don't have to be overly concerned about moisture contamination over time and IMO I get a firmer pedal and better control at the limit using it. Yes, it is expensive but 1L thoroughly flushes the entire system and except for an occasional front caliper bleed that doesn't require much add'l filling it is pretty much hands-off. Otherwise, I just do a complete flush on an annual basis. So while $65/L seems relatively expensive it's not really a continuous cost and for the added protection relative to the risk IMO it's worth it. Let's face it, most of you blow that or more on many other things of minor benefit or value. With the other fluids you better be flushing out the entire system on a regular basis to ensure you are getting the high temp protection. It's not much of an advantage on a vehicle that is only used for the street, that is why I don't recommend it for general use.
> 
> BTW, for a dry boiling point difference of 4 degF you'd have to be pretty damn lucky for that to be the deciding factor between boiling and not boiling and except for extreme racing brake pads or moisture in the system it's usually the pad that gives up before a quality high temp fluid. Also, if you evaluate the dry vs wet range between the fluids it isn't going to take much moisture absorption before the other fluids are dropping below the boiling point of SRF at the same moisture level, but that precludes the fact that SRF is more moisture resistant than the other high-temp fluids. So again, if you are into maintenance and doing a complete flush before every high temp excursion you can get by with the cheaper fluids.
> 
> Finally, I'm not advocating anyone else doing the same. I'm only said, "... *I* switched to Castrol SRF and never looked back". I like it, it works for me and IMO the added cost isn't significant; end of story.


We're in total agreement on every point except, possibly, for the pedal firmness. There shouldn't be any difference between any DOT 4 brake fluid as far as pedal firmness, assuming you got all the air out. Any difference between fluids that you've experienced is likely due to the effectiveness of the particular bleed. You probably got lucky on your first SRF bleed and displodged a pesky bubble. I can see how that would convince someone that it was better. Thus far, I've seen no data to support a lower compressibility of SRF over other fluids. If that was the case and it did make a noticable difference, I would be switching over all my street cars in a heartbeat. As you point out, $65 is not much to spend for a tangible upgrade.

I don't understand your comment about having more control at the limit. Can you elaborate? Or is it simply because you have a firmer pedal?

SRF really is a remarkable fluid and can allow you to go for several track events without having to bleed with fresh fluid. My understanding, at a very high level, is that it reacts with moisture to chemically change it so the boiling point isn't as dramatically reduced as other fluids that become saturated.

For those who are only driving on the street, even the Motul 600 at a fraction of the price is overkill. But if it makes you feel better or have more confidence in your brakes, $65 is not a huge price to pay. And the case could easily be made that the high wet boiling point makes it a good choice for the track for drivers who don't have the time or the means to bleed the brakes frequently.


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## sph17 (Oct 5, 2003)

*For regualar folks*

I purchased some Valvoline SynPower (the can says "Exceeds DOT 3 & DOT4") Synthetic Formula Brake Fluid for an older MB. It dosn't claim to be a DOT 5.

If I am out of warrantee with my E39 is this brake fluid OK to use?


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## DZeckhausen (Mar 11, 2003)

sph17 said:


> I purchased some Valvoline SynPower (the can says "Exceeds DOT 3 & DOT4") Synthetic Formula Brake Fluid for an older MB. It dosn't claim to be a DOT 5.
> 
> If I am out of warrantee with my E39 is this brake fluid OK to use?


That fluid is perfectly fine to use, in or out of warrantee, on the E39. If you are going to track the car, you probably want something with a higher dry and wet boiling point, like ATE or Motul. But for the street, the Valvoline stuff is perfectly fine and it's readily available at a very low price.


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## sph17 (Oct 5, 2003)

DZeckhausen said:


> That fluid is perfectly fine to use, in or out of warrantee, on the E39. If you are going to track the car, you probably want something with a higher dry and wet boiling point, like ATE or Motul. But for the street, the Valvoline stuff is perfectly fine and it's readily available at a very low price.


Thanks!

<sph17>


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