What brake fluid do you use?

[STi_traitor]

Originally Posted by sawzall

We use SRF in both our track day cars and our race car. The main reason we like SRF over the other fluids is because you can basically do a flush once a year, and then bleed as needed, and never have to worry about the fluid boiling. It really is the best stuff out there.

Motul RBF is a fantastic fluid, and generally you can't go wrong with it. If you do boil it (which can be tough to do), it's cheap enough to flush. We used to run Motul, and found that we would end up flushing the fluid 2-3 times a track season, and we would bleed pretty much at the end of every day.

Thanks for the input!

[1MOREMOD]

Originally Posted by STi_traitor

Not just the Ring. I am curious what others use for state side tracks as well. I am going to return to the states at some point.

Plus this is great to get a idea of what everyone uses and to maybe try out new fluids like you stated earlier.

good plan. im not a frequent bleeder or at least in the past i wasnt so maybe i would benefit from the srf. but i have the wheels off so often i could just do a flush every other month with the ate and have it work out to be similar priced. i may give that ap racing 660 a shot also. for now i have a bunch of ate that will last me for quite a while.

[STi_traitor]

Originally Posted by 1MOREMOD

good plan. im not a frequent bleeder or at least in the past i wasnt so maybe i would benefit from the srf. but i have the wheels off so often i could just do a flush every other month with the ate and have it work out to be similar priced. i may give that ap racing 660 a shot also. for now i have a bunch of ate that will last me for quite a while.

Same here, I have usually only touched my fluid once a year. Maybe I will start being more active with bleeding and see if there is a significant difference which I doubt. To each his own I guess. Did the AP 660 come with the kit?

[1MOREMOD]

Originally Posted by STi_traitor

Same here, I have usually only touched my fluid once a year. Maybe I will start being more active with bleeding and see if there is a significant difference which I doubt. To each his own I guess. Did the AP 660 come with the kit?

no someone above mentioned the AP as a higher dry boiling pt alternative than the srf for less money. right now i have had my car together for a couple months and it has been flushed twice and bled several times. mostly due to the st-40s going in.

[sawzall]

Originally Posted by 1MOREMOD

no someone above mentioned the AP as a higher dry boiling pt alternative than the srf for less money. right now i have had my car together for a couple months and it has been flushed twice and bled several times. mostly due to the st-40s going in.

The boiling points for AP PRF 660 is - Dry 325°C and Wet 204°C
The boiling points for Castrol SRF is - Dry 310°C and Wet 270°C

PRF660 usually sets for around $30/500ml which is around $60/l. At Gruppe Werks, we sell SRF for $70/1000ml so it ends up not being much more than PRF660.

Generally, we tell our clients to look at the wet boiling points. If your brake fluid has been in for a month, your boiling point is going to be somewhere in between the dry and wet points. And with the SRF, the performance of the brake fluid won't degrade as much over time as other DOT4 fluids, which is why we think SRF is superior, and generally cost effective.

On a similar note, Brembo HTC 64T has an even higher dry boiling point of 335°C, but a wet boiling point of 204°C and costs around $33/500ml.

PS. Sorry for using the metric system everywhere - i'm Canadian - Farenheight just doesn't make sense to me!

[1MOREMOD]

Originally Posted by sawzall

The boiling points for AP PRF 660 is - Dry 325°C and Wet 204°C
The boiling points for Castrol SRF is - Dry 310°C and Wet 270°C

PRF660 usually sets for around $30/500ml which is around $60/l. At Gruppe Werks, we sell SRF for $70/1000ml so it ends up not being much more than PRF660.

Generally, we tell our clients to look at the wet boiling points. If your brake fluid has been in for a month, your boiling point is going to be somewhere in between the dry and wet points. And with the SRF, the performance of the brake fluid won't degrade as much over time as other DOT4 fluids, which is why we think SRF is superior, and generally cost effective.

On a similar note, Brembo HTC 64T has an even higher dry boiling point of 335°C, but a wet boiling point of 204°C and costs around $33/500ml.

good points. would be interested to know how fast you go from dry to wet with time.

[sawzall]

Originally Posted by 1MOREMOD

good points. would be interested to know how fast you go from dry to wet with time.

That's the million dollar question! There are a ton of variables that go into factoring how quickly your fluid absorbs water. Condition of hard and soft brake lines, caliper condition, climate all factor in. The main things are to make sure all your caliper seals (including piston seals) are in good condition, along with your soft brake lines. Those are the main areas where moisture can get in, and keeping those maintained will make sure your fluid stays as dry as possible.

[STi_traitor]

Originally Posted by sawzall

Generally, we tell our clients to look at the wet boiling points. If your brake fluid has been in for a month, your boiling point is going to be somewhere in between the dry and wet points. And with the SRF, the performance of the brake fluid won't degrade as much over time as other DOT4 fluids, which is why we think SRF is superior, and generally cost effective.

You are speaking of clients with heavy track use? You and a few others are starting to lean me in the direction of sticking with SRF. Thanks for the solid information.

[1MOREMOD]

Originally Posted by sawzall

That's the million dollar question! There are a ton of variables that go into factoring how quickly your fluid absorbs water. Condition of hard and soft brake lines, caliper condition, climate all factor in. The main things are to make sure all your caliper seals (including piston seals) are in good condition, along with your soft brake lines. Those are the main areas where moisture can get in, and keeping those maintained will make sure your fluid stays as dry as possible.

well i should be good for a while then shouldnt absorb too fast. i have new st-40s so new seals on the pistons and new lines. should i quit leaving the cap off the master cylinder?

[STi_traitor]

Originally Posted by 1MOREMOD

well i should be good for a while then shouldnt absorb too fast. i have new st-40s so new seals on the pistons and new lines. should i quit leaving the cap off the master cylinder?

No, leave it off in case there is too much pressure. Imagine hitting the brake pedal and its like kicking a wall! No good....

[sawzall]

Originally Posted by 1MOREMOD

well i should be good for a while then shouldnt absorb too fast. i have new st-40s so new seals on the pistons and new lines. should i quit leaving the cap off the master cylinder?

LOL.

On a serious note, after particularly hot days at the track, don't forget to check your bleeder valves. Last time we were at the Glen, one member's bleeder valve came loose (we assume from the heat and subsequent contraction), and lost brake pressure in his passenger rear! Luckily he was able to get his car into the garage with no incidents.

[1MOREMOD]

Originally Posted by sawzall

LOL.

On a serious note, after particularly hot days at the track, don't forget to check your bleeder valves. Last time we were at the Glen, one member's bleeder valve came loose (we assume from the heat and subsequent contraction), and lost brake pressure in his passenger rear! Luckily he was able to get his car into the garage with no incidents.

ive never heard of that. good to know i guess but if that happens im going to assume i didnt tighten properly. i had a freeze plug come out on the front of my block, alsoa rare occurrence. maybe im just lucky.

[r53s65e90]

MOTUL RBF 600 after I boiled fresh ATE gold going into turn 2 at Laguna Seca. That was with stock calipers and stoptech street performance pads with about 7mm of pad material.

[1MOREMOD]

Originally Posted by r53s65e90

MOTUL RBF 600 after I boiled fresh ATE gold going into turn 2 at Laguna Seca. That was with stock calipers and stoptech street performance pads with about 7mm of pad material.

How do you know when you boil your fluid. Just making that assumption based on an instance of fade? I've had fade tons of times and just cooled it for a turn or 2 then right back at it.

[Drifty//]

Originally Posted by STi_traitor

Did the AP 660 come with the kit?

No, the AP Racing kit was drop shipped from Stillen (the US distributor) and did not include any fluid. I got my AP PRF 660 from SafeRacer.com.

It's true that the wet boiling point is a lot lower than SRF (204° C vs 270° C). But it's not so bad since the recovery on the AP fluid is so good (95%, they say). So, if you go too long between flushes (which is where the wet boiling point starts to come into play) and do manage to boil it, you're still not running a huge risk.

[Drifty//]

BTW, because I have no idea how close I am to boiling, the recovery property is the main reason I run the AP fluid. I guess I could just switch to SRF and assume I'll never boil it, but the good recovery sounds safer to me than simply hoping the higher wet boiling point of SRF is high enough.

[edwinm3]

SRF and forget about it for awhile

[r53s65e90]

Originally Posted by 1MOREMOD

How do you know when you boil your fluid. Just making that assumption based on an instance of fade? I've had fade tons of times and just cooled it for a turn or 2 then right back at it.

Pedal went to the metal (or this is how it felt). This I assume means air bubbles increased the compressibility of the fluid. Other fade I experienced before was different: it required more pressure for required stopping power, but the pedal was firm and did not dive. So I assumed I boiled it and replaced it with RBF 600.

It was a bit scary. Fortunately I had scrubbed enough speed to be ok and the brakes continued to work: The travel just got enormous.

Sounds reasonable?

[1MOREMOD]

Originally Posted by r53s65e90

Pedal went to the metal (or this is how it felt). This I assume means air bubbles increased the compressibility of the fluid. Other fade I experienced before was different: it required more pressure for required stopping power, but the pedal was firm and did not dive. So I assumed I boiled it and replaced it with RBF 600.

It was a bit scary. Fortunately I had scrubbed enough speed to be ok and the brakes continued to work: The travel just got enormous.

Sounds reasonable?

yep ive had it feel like i overheated the pads to get fade and required a lot of pressure and still didnt do much but never just to the floor feeling. my assumption is i have never boiled the fluid only overheated the pads.

[sawzall]

Originally Posted by STi_traitor

You are speaking of clients with heavy track use? You and a few others are starting to lean me in the direction of sticking with SRF. Thanks for the solid information.

Woops. I failed to answer this question earlier.

I am generally speaking about people who track regularly. Part of the factor is the condition of the car, which really has nothing to do with tracking (if anything i've found people who track are better at maintaining their car). If you go to the track on a regular basis, and find your brakes getting soft (you may not go too often but the tracks you go to could require a ton of brakes) then you ought to at least consider a better brake fluid.

[Endless619]

Originally Posted by STi_traitor

My bad, I figured talking boiling points and what not would have made that clear. I will make a update.



Not just the Ring. I am curious what others use for state side tracks as well. I am going to return to the states at some point.

Plus this is great to get a idea of what everyone uses and to maybe try out new fluids like you stated earlier.

It is not clear to the average layman.

Some of us know but we like folks to be thorough with their posts. I don't know how many times I have had to tell folks selling Volks to put the damn color.

Thank you.

[Transfer]

I'm in the ATE super camp. I do about 6-7 track days a year and do a bleed once or twice a year.