Brake Fluid Recommendations

[Nix]

OK so I want to change my brake fluid and im looking for suggestions. Other than OEM Honda fluid what do you performance peoples like to use? I am specifically looking for better pedal feel. I know brake fluid absorbs moisture from the air and that leads to spongy pedal feel. Would just draining, bleeding, and refilling with OEM fluid restore pedal feel? Or since im at it anyway, change to a better fluid?

Also im willing to do this once a year so longevity is not a super high priority. Thanks!

 

[Monk]

Dot 4 is what you need.... forget 5....... Once a year is the best, that the real problem.

-the simlest way to think of brake fluid is that the higher the DOT # the higher the temp, and newer the standard.
(note: this is very simplistic and vauge, and probably doesnt take into account everything.)
think of it as dot 4 is the newer version of dot 3. made for newer systems (types of materials) and has a higher dry and wet boiling point.
-dry is the temp brake fluid boils when new. with a moister content of less that whatever percent. and wet is when the moister content is above a certain percent...used. as brake fluid absorbs moister.
-dot 5, and 5.1 (i belive) are both silicone based and are NOT compatible with other systems, w/o a complete and thurough flush. even still leaks can occur as the system was not designed for it.
-unless you have a problem with your brakes boiling there is no reason to "upgrade". as the life of all fluid is about the same. (e.g. going from dot 3 to 4 will give you say a 100 deg higher boiling point) something like a motol 600 means it goes up to around 600 deg dry before it boils, so unless your gonna circle track your hundy its a waste of money...imo.
-i constantly tow my race car and trailer ~5000lbs and have never boiled the fluid. toyota would be nuts to advertise a towing capacity of x amount and not provide the proper fluid.
-if you really want to "upgrade" for whatever reason DOT 4 should be plenty sufficient. ive used castrol gt lma dot 4 in the race car and like it. its cheap, and you dont have to worry about fluid incompatibility. imo even thats a waste. brake fluid is held to a pretty high standard. even the cheap dot 3 (or whatever) still has to meet temp standards.
-google BITOG and read the brake fluid sec.

 

[webby]

jrotax101 may be up on this, but I do recall reading a list of fluids & their boiling points on HT a year or so back.

Here it is:

=========
Time to post up the list again for 2011 because there is some new product and some updated pricing since the last list.

Newest member is Performance Friction RH665 DOT4 fluid with guaranteed minimum dry boiling point of 323C and wet BP of 195C, from Performance Friction Brakes (UK) Ltd.

http://www.performancefrictionbrakes....pdf?pageId=47

and Brembo HTC 64T racing only fluid with a dry boiling point of 335C (635F)

Prospeed RS683 with a 683F has the highest dry boiling point and also the highest wet boiling point of 439F:
sold here: http://www.pegasusautoracing.com/pro...asp?RecID=1036

and how about this for high tech brake fluid PROJECT MU G/FOUR 335 :
"Totally reliable brake fluid that combines a boiling point so high it’s in another dimension with durability and maintainability. You know it’s time to change your G-four 335 brake fluid, which can reach close to 300C, when the color changes from green to crystal clear."
http://www.project-mu.co.jp/en/produ...her_fluid.html
...so you know when it's time to change it. and at about $22.50 per 0.5 litres, it is the best deal having the second highest dry boiling point. Not that much more than the el cheapo stuff I've been using for years, Motul RBF 600.

Lately I'm on AP Racing PRF 660, which seems very, very good.


ARRANGED BY DRY BOILING POINT(some prices from my 2010 list and some are updated, check with your favorite supplier, and look for case prices so you can change it often):

DRY:401F -- WET:284F --- DOT3 MINIMUM (GLYCOL BASE)
DRY:446F -- WET:311F --- DOT4 MINIMUM (GLYCOL BASE)
DRY:500F -- WET:356F --- DOT5 MINIMUM (SILICONE BASE)
DRY:500F -- WET:356F --- DOT5.1 MINIMUM (GLYCOL BASE)
DRY:500F -- WET:???F --- FORD HEAVY DUTY DOT 3 PM-1C (new since 2006)
DRY:527F -- WET:302F --- AP RACING 551 ($12.799/0.5L OR 16.9 OZ)
DRY:527F -- WET:347F --- VALVOLINE SYNPOWER DOT3 & DOT4
DRY:536F -- WET:388F --- ATE SUPERBLUE/TYP200 ($13.99/1L)
DRY:550F -- WET:284F --- FORD HEAVY DUTY DOT 3 PM-1 (pre 2006) ($4/12 OZ)
DRY:570F -- WET:284F --- WILWOOD 570 ($7.95/12 OZ)
DRY:570F -- WET:284F --- PERFORMANCE Friction Z rated ($6.27/16 OZ)
DRY:572F -- WET:410F --- AP RACING 600 ($19.95/0.5L OR 16.9 OZ)
DRY:590F -- WET:???F --- TILTON TBR-1 ($11.95/0.25L) (new since 2006)
DRY:590F -- WET:518F --- CASTROL SRF ($74.99/1.0L 0R 33.8 OZ)
DRY:593F -- WET:421F --- MOTUL RBF 600 ($15.99/0.5L OR 16.9 OZ)
DRY:601F -- WET:399F --- BREMBO LCF 600 PLUS ($19.95/0.5L OR 16.9 OZ)
DRY:608F -- WET:390F --- AP RACING PRF660 ($29.95/0.5L OR 16.9 OZ)
DRY:610F -- WET:421F --- NEO SYNTHETICS SUPER DOT 610 ($11.95/12 OZ)
DRY:613F -- WET:424F --- ENDLESS RF-650 ($33.00/0.5L OR 16.9 OZ)
DRY:617F -- WET:399F --- MOTUL RBF 660 ($28.99/0.5L OR 16.9 OZ)
DRY:617F -- WET:383F --- PFC RH665($28.99/0.5L OR 16.9 OZ)
DRY:622F -- WET:???F --- TILTON TSR-1 ($17.95/0.25L) (new since 2006)
DRY:626F -- WET:???F --- FERODO FSF050 Super Race Brake Fluid ($39.99/0.5L OR 16.9 OZ)
DRY:626F -- WET:417F --- WILWOOD EXP 600 ($18.99/0.5L 16.9 OZ)
DRY:635F -- WET:???F --- BREMBO HTC 64T ($32.00/0.5L 16.9 OZ)
DRY:635F -- WET:430F --- PROJECT MU G/FOUR 335 ($45.00/1.0L 33.8 OZ)
DRY:683F -- WET:439F --- PROSPEED RS683 ($39.99/0.5L OR 16.9 OZ)

ARRANGED BY WET BOILING POINT:

DRY:500F -- WET:???F --- FORD HEAVY DUTY DOT 3 PM-1C (new since 2006)
DRY:590F -- WET:???F --- TILTON TBR-1 ($11.95/0.25L) (new since 2006)
DRY:622F -- WET:???F --- TILTON TSR-1 ($17.95/0.25L) (new since 2006)
DRY:626F -- WET:???F --- FERODO FSF050 Super Race Brake Fluid (new since 2009)
DRY:635F -- WET:???F --- BREMBO HTC 64T
DRY:401F -- WET:284F --- DOT3 MINIMUM
DRY:570F -- WET:284F --- WILWOOD 570
DRY:570F -- WET:284F --- PERFORMANCE Friction Z rated
DRY:550F -- WET:284F --- FORD HEAVY DUTY DOT 3
DRY:527F -- WET:302F --- AP RACING 551
DRY:446F -- WET:311F --- DOT4 MINIMUM
DRY:527F -- WET:347F --- VALVOLINE SYNPOWER DOT3 & DOT4
DRY:500F -- WET:356F --- DOT5.1 MINIMUM (GLYCOL BASE)
DRY:500F -- WET:356F --- DOT5 MINIMUM (SILICONE BASE)
DRY:617F -- WET:383F --- PFC RH665 (new since 2011)
DRY:536F -- WET:388F --- ATE SUPERBLUE/TYP200
DRY:608F -- WET:390F --- AP RACING PRF660
DRY:601F -- WET:399F --- BREMBO LCF 600 PLUS
DRY:617F -- WET:399F --- MOTUL RBF 660
DRY:572F -- WET:410F --- AP RACING 600
DRY:626F -- WET:417F --- WILWOOD EXP 600
DRY:593F -- WET:421F --- MOTUL RBF 600
DRY:610F -- WET:421F --- NEO SYNTHETICS SUPER DOT 610
DRY:613F -- WET:424F --- ENDLESS RF-650
DRY:635F -- WET:430F --- PROJECT MU G/FOUR 335
DRY:683F -- WET:439F --- PROSPEED RS683 (new since 2010)
DRY:590F -- WET:518F --- CASTROL SRF


Some fluids on the manufacturer's web site did not specify wet boiling point, so I used the relevant DOT 3 value.

Water absorption:
DOT 3: This brake fluid has a glycol base with additives. It is clear to amber in color. It is hygroscopic (meaning it absorbs moisture) and has a minimum dry boiling point of 401F (205C) minimum and a minimum wet boiling point of 284F (140C). It will absorb 1 to 2 percent of water per year depending on climate and operating conditions.

Castrol SRF remains as always the Wet boiling champ. I don't know of any other new ones.

Now of course boiling temp is not the only thing to consider, as compressibility, water absorption rate, recovery, viscosity index, etc all play a part. But without a brake dyno, that data is hard to get.

Here is an interesting chart of brake fluid compressibility: http://www.hrpworld.com/client_image...pdf_4745_5.pdf

 

[Monk]

We've gone though this on my MC forum a thousand times and it comes out to "use dot 4" and change it at least once a year.

 

[Monk]

This is what I was looking for, this guys knows his Stuff......... Called BusylittleShop

I coach my customers that instead of looking at brake fluid as
D.O.T. 3/4 versus D.O.T. 5, we should see the issue as glycol versus
silicone. This represents the larger division of type, and comparing
D.O.T. ratings just isn't significant, especially since D.O.T. 5
fluids are now available in glycol formulation. Glycol fluids have
improved until they now meet D.O.T. 5 standards. D.O.T. 5.1 for
example, is a glycol fluid designed for certain ABS systems having
mechanically cycling proportion valves. So now we have D.O.T. 3, 4, 5,
and 5.1, with all but the 5 designation being glycol, while D.O.T 5 is
silicone.

The real way to compare brake fluids is by deciding what is important
to you. Is silicone fluid's safety around paint and plastic more
important than yearly changes and a softer action? Its higher boiling
point, the reason for its development and at one time its strong suit,
is now academic, since D.O.T. 5 glycol (5.1) fluids are now widely
available. Glycol fluid therefore is, for most of us, the better brake
fluid, and the best just may be the 5.1, if the highest boiling point,
which is really a moisture tolerance measurement, matters.

As Glycol progressively contains more moisture it will start to turn
golden, then light brown, Eventually, if left unchanged beyond the
recommended service interval, the fluid will become dark brown,
indicating high amounts of water absorption and thus badly
contaminated fluid... The other problem with this continuous exposure
to moisture is that moisture makes the brake fluid more compressible.
You don't want any compressibility in a brake system. For every
millimeter that the lever moves, you expect a proportionate movement
of the brake pads against the disc. If you don't have that, you have
an unreliable and dangerous brake system. Unfortunately, brake fluid
becomes more compressible as it increases in water content. Water
contains hydrogen, and in response to many heat cycles like at a track
the brake fluid soon has air mixed into it as well as moisture and may
boil... in fact some track day tech inspectors check for brown fluid...

On the practical side, beware that glycol and silicone brake fluids
are hugely incompatible with each other. Mixing even small amounts
will create a sludge that looks amazingly like Italian salad dressing
and is about as effective as a brake fluid

Boiling point of Glycol based brake fluids
DOT 3 205 °C (401 °F)
DOT 4 230 °C (446 °F)
DOT 5 260 °C (500 °F)
DOT 5.1 270 °C (518 °F)

Boiling point of Silicone based brake fluids
DOT 5 260 °C (500 °F)

 

[jrotax101]

Not much to add.

Flush once a year and be wary of the higher BP fluids being more hygroscopic.

I use Motul RBF600. Easily obtainable as it's primarily used on race bikes.

 

[Nix]

Thanks guys.

Anything that I should watch out for that might eat components or Honda parts or are they all fairly compatible?

 

[jrotax101]

Don't get it on your paint..

and I don't like superblue.