Brakes 101 (and 102)

[aklackner]

Out of curiosity what’s everyone using for brake fluid and why?

I have ATE 200 in currently but see quite a few in track forums that seem to consider this a lower end choice. With dry boil point list at 280c(536f) it doesn’t seem that far off of something like Motul 600 (312C) I feel like I’m missing something.

In competition I could see it but wonder if the extra ~60f is really the driver here or something else going on.

I think my track setup should look like:
OEM abs & booster
J’s SS lines
Front Caliper: Mugen AGBS (S2k) - smaller caliper saves some weight, 300mm rotor improves cooling, but maintains oem brake bias
Front Rotor: Racing Brake 2 piece RSX-S rotors (300mm x 25mm) - improved cooling, even pad wear, and looses a couple lbs on standard 300mm rotor.
Front Pad: S2k EBC Blue - for street I’ve liked yellow so figured I’d give blue a try. They are supposed to be street rated so won’t have any concerns about swapping these and dedicated rotors in before heading out to the event. Also supposed to be kinder to rotors so the rings might last a touch longer.

Rear caliper: OEM ITR
Rear Rotor: Racing Brake slotted & drilled - mostly to match the front but should be quality and help even out pad wear.
Rear pad: RSX EBC Blue - wanted same compound front and rear to maintain bias

Is everyone running pad shims front and rear? It looks like Helms doesn’t show them in the insides (piston side) for ITR? In theory this will improve heat transfer to pistons and make pads run cooler. Is there a reason to either run or not run the shims on OEM style pads on track?

[aw614]

IIRC the 97 had 2 bolts holding the arm, the 98+ had a sort of pin in one position and a bolt on the other. Shapes on the caliper mating side may have been slightly different too.

I don’t think I have pictures of the bracket but here’s the mating surface on the OEM 98+ caliper. You can see one side for the pin the other threaded for a bolt.



Was out checking torque so here’s the 98+ arm. You can sort of see the inset where the locating pin is that goes into the non-threaded hole in the calipers.

Thanks, it looks like I got a set of 98+ calipers, odd about that pin, I thought it was two bolts or something, but the parts diagram wasn't clear about it when I looked at it.

On the fluid, the local motorcycle shop has Motul RBF 600 it only costs 20 dollars, and not many other places carry Type 200. It might have less fluid than Type 200, but it is much easier for me to buy it locally vs say waiting for delivery. Honestly, if I was just doing mostly autocross and street use I would stick with Type 200 or even Pentosin Super DOT4 fluid both were fine for that sort of use. But it could also depend on the types of tracks you run, it is just cheap insurance to have to run the higher temp fluid if the track you use is hard on brakes.

For the track days I've run, I've kept the pad shims installed. The Nissin track pads I bought to try for an event at the end of the month came with shims for both sides of the pad. I tend to just swap only the fronts, but keep the stock rear pads on. Autocross and street use I use stock pads all around, but I have considered running the same compound Front and rear.

[coolhandluke]

Out of curiosity what’s everyone using for brake fluid and why?

I have ATE 200 in currently but see quite a few in track forums that seem to consider this a lower end choice. With dry boil point list at 280c(536f) it doesn’t seem that far off of something like Motul 600 (312C) I feel like I’m missing something.

I ran ATE SuperBlue / 200 for years until I stepped up in speed, tire compounds, and pads. I'm currently running Motul RBF 600. If ATE is working, keep with it. Regardless of fluid, make sure it is <1yr old. I flush at the beginning of every track season.

Is everyone running pad shims front and rear? It looks like Helms doesn’t show them in the insides (piston side) for ITR? In theory this will improve heat transfer to pistons and make pads run cooler. Is there a reason to either run or not run the shims on OEM style pads on track?

I have never run pad shims. I can see potential for benefits once the pad wear allows the space, especially for Spoon caliper users. Once the Spoon's get extended the brakes overheat once below ~40% pad material.

FK8 owners do run pad shims. They are often positioned to help prevent pad fade and are made of fancy materials, ie higher price tag. I haven't test before/after but it could be worth researching.

[hondarcb]

I run Motul 660. Castrol SRF is king, but expensive. The biggest benefit is for cars with longer service intervals - it can go longer between changes while maintaining performance. I have no direct experience with SRF. I flush my 660 at the beginning of each season and don't touch it for the duration.

[aklackner]

I run Motul 660. Castrol SRF is king, but expensive. The biggest benefit is for cars with longer service intervals - it can go longer between changes while maintaining performance. I have no direct experience with SRF. I flush my 660 at the beginning of each season and don't touch it for the duration.

Is that due to moisture absorption differences, corrosive properties, or general break down/decline in performance?

Any difference in booted piston oem type calipers vs seal only calipers in fluid life? I’m assuming this would be more evident in south east or where there’s generally high ambient humidity if driven by absorption?

Additional thought/query - for those with Spoon calipers (seal only IIRC) how frequently do you feel you need to service/replace the caliper seals? Do you test/monitor brake fluid for water content since I believe this has greater exposure without OE piston boots?

For those tracking with OEM booted style calipers any issues with boots super heating/melting? I believe this risk was the reason I saw for most performance brakes not booting the pistons as well as possible better visibility/identification of seal damage/leaks that would be hidden by a boot.

Anyone test for evidence of corrosion in brake fluid? I saw Phoenix Systems has a quick test strip kit that you dip in the reservoir.

ATE 200 is <$20 for a liter on Amazon. Add a bleed kit with one way valve (love my Phoenix Systems bottle) and flushing my system takes 15mins, less with help. I think I’m just running this after any event as standard practice also gives an opportunity to do an inspection and can be done at the same time I swap the pads and rotors back to brembo blanks and ebc yellows for street use.

[aklackner]

This brings to mind the environmental aspect of more frequent fluid changes. Oil recycling near me is easy but I don’t know if I’ve run into anyone accepting hydraulic fluids for recycling (only toxic disposal).

Are there more environmental options for managing brake fluids?

[hondarcb]

I believe the big benefit of the SRF is slower moisture absorption.

I wouldn’t think caliper type would make a difference.

I raced 3 seasons on stock calipers with OEM seals. Dust seals would get baked due to temperatures, but the pressure seals were always fine. Never had a leaking caliper. I stopped installing the dust seals. For a comparison of brake wear, I’d go through a set of rotors in 2 weekends. The StopTech dust seals in my Porsche Brembos also bake, and are unnecessary - for a race car anyway.

Brake fluid is so cheap and easy to change, and the potential consequences of a brake failure are so great, it’s not a risk I’m worth taking. Pretty proactive with brake stuff.

If you’re driving cars for a hobby, the waste disposal from the minimal amount of brake fluid seems a small factor in the overall environmental impact, though the thought is surely well intended.

[coolhandluke]

...Additional thought/query - for those with Spoon calipers (seal only IIRC) how frequently do you feel you need to service/replace the caliper seals?

Cliffs: I've yet to need to service a set.

I've had three sets of Spoon Twinblock calipers over the last ~14yrs. I could tell a difference between the older/more tracked set side by side, but this could be said for any caliper with low miles versus high miles. I purchased a Spoon rebuild kit from VPR Motorsports at Type R Expo 17, but I never needed them, so now I will just sell it.

Do you test/monitor brake fluid for water content since I believe this has greater exposure without OE piston boots?

My "test" is when the fluid boils mid-season. My proactive approach matches hondacrb, I flush the fluid at the start of each track season.

[novtecforme]

Does anyone have experiences with the Endless RF-650? I know they’re crazy expensive like the SRF.

[coolhandluke]

Does anyone have experiences with the Endless RF-650? I know they’re crazy expensive like the SRF.

I know a few with first-hand experience. I will ask them to chime in to help document their feedback.