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Which brake fluid for track? Owners supplement says NO silicone

meterman

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So i've run Maxima 600+ racing brake fluid and Motul's 600 in my 07 GT500, I'm getting ready to switch out fhe factory brake fluid in my GT350R but when I read the owners supplement it says specifically NOT to use silicone brake fluids which Maxima, Motul and Castrol SRF all are silicone.

Page 50 of the owners supplement:
Hydraulic Brake System
Use only Motorcraft DOT 4 LV High Performance Brake Fluid or equivalent meeting WSS-M6C65-A2 and ISO 4925 Class 6. Use of any fluid other than the recommended fluid may cause brake system damage. Prior to track use, replace brake fluid with fresh Motorcraft/Ford DOT 4 LV High Performance Brake Fluid or other DOT compliant fluid with a dry boiling point
greater than 500Ā°F (260Ā°C) from a sealed container. Do not use silicone or DOT 5 brake fluids.

So what's the down side to silicone?

Jim
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JAJ

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So i've run Maxima 600+ racing brake fluid and Motul's 600 in my 07 GT500, I'm getting ready to switch out fhe factory brake fluid in my GT350R but when I read the owners supplement it says specifically NOT to use silicone brake fluids which Maxima, Motul and Castrol SRF all are silicone.

Page 50 of the owners supplement:
Hydraulic Brake System
Use only Motorcraft DOT 4 LV High Performance Brake Fluid or equivalent meeting WSS-M6C65-A2 and ISO 4925 Class 6. Use of any fluid other than the recommended fluid may cause brake system damage. Prior to track use, replace brake fluid with fresh Motorcraft/Ford DOT 4 LV High Performance Brake Fluid or other DOT compliant fluid with a dry boiling point
greater than 500Ā°F (260Ā°C) from a sealed container. Do not use silicone or DOT 5 brake fluids.

So what's the down side to silicone?

Jim
Silicone brake fluid is not a good choice because it doesn't absorb water. Water always seeps into the braking system and because DOT 5 brake fluid does't absorb it, it stays as water, which boils at 212 degrees F. Even wet DOT 3 brake fluid boils at a much higher temperature than that.

That said, Maxima, Motul and SRF are all glycol based - they are not silicone. Silicone fluid is quite rare, as it should be.
 

pilotgore

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So i've run Maxima 600+ racing brake fluid and Motul's 600 in my 07 GT500, I'm getting ready to switch out fhe factory brake fluid in my GT350R but when I read the owners supplement it says specifically NOT to use silicone brake fluids which Maxima, Motul and Castrol SRF all are silicone.

Page 50 of the owners supplement:
Hydraulic Brake System
Use only Motorcraft DOT 4 LV High Performance Brake Fluid or equivalent meeting WSS-M6C65-A2 and ISO 4925 Class 6. Use of any fluid other than the recommended fluid may cause brake system damage. Prior to track use, replace brake fluid with fresh Motorcraft/Ford DOT 4 LV High Performance Brake Fluid or other DOT compliant fluid with a dry boiling point
greater than 500Ā°F (260Ā°C) from a sealed container. Do not use silicone or DOT 5 brake fluids.

So what's the down side to silicone?

Jim
I like Motul 600 specifically because itā€™s readily available and the price is reasonable. SRF seems to be the superior product, but the prices recently have reached stupid territory.
 

Slopoke

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You could try 5.1. It's got a higher boiling point compared to 4.0 fluid. DON'T confuse this with 5.0, 5.0 is the silicone fluid.
 
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meterman

meterman

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Ok, my bad, DUH!! I said silicone, and misread the label, it's synthetic.

so let's just pretend I didn't even post this thread.
 

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BimmerDriver

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I tried but I just can't ignore the thread, LOL. I have used ATE brake fluid for many years, it's much cheaper than Motul and has nearly as high boiling points.

Back when I was a track rat, I was flushing brake fluid every few months. Now it's just twice a year.
 

honeybadger

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Castrol SRF is the only direction I'd go. I've tried the factory stuff - boiled it. Tried Motul 600 - boiled it. Currently Motul 660 in it now due to the SRF shortage when I needed to flush - it was okay.

I ran SRF for 3 years straight and NEVER had an issue with it. I've gotten it hot enough to have brake fade, but once it cooled down, it was back to normal. The others were done once boiled. Also note that SRF comes in 1 liter bottles vs. half liter. So it's really only a bit more bottle.

Brakes are literally the most important part of the car...especially on track. Not the area to penny pinch, IMHO.

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pilotgore

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Castrol SRF is the only direction I'd go. I've tried the factory stuff - boiled it. Tried Motul 600 - boiled it. Currently Motul 660 in it now due to the SRF shortage when I needed to flush - it was okay.

I ran SRF for 3 years straight and NEVER had an issue with it. I've gotten it hot enough to have brake fade, but once it cooled down, it was back to normal. The others were done once boiled. Also note that SRF comes in 1 liter bottles vs. half liter. So it's really only a bit more bottle.

Brakes are literally the most important part of the car...especially on track. Not the area to penny pinch, IMHO.

SV503 GT350 Brushed Bronze Tinted Honeybadger (23 of 26).jpg
Where can I get those awesome rotor illuminating LEDā€™s like you have....? Definitely my next upgrade!!
 

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Flyhalf

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I use motul 660
Great compromise betweem price and quality.
Srf is the king of the fluid. If you dont track the car often i think it could be an overkill.
But like Kevin said
brakes are important. :)
Alessandro
 

WItoTX

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So I am bumping this thread up because I've read that srf is bad for the clutch lines. Since the clutch and brakes share the same reservoir/fluid, has anyone has issues with their clutch since swapping to srf or even 660?

If so, did you add a clutch reservoir with regular DOT4 fluid?
 

honeybadger

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So I am bumping this thread up because I've read that srf is bad for the clutch lines. Since the clutch and brakes share the same reservoir/fluid, has anyone has issues with their clutch since swapping to srf or even 660?

If so, did you add a clutch reservoir with regular DOT4 fluid?
Iā€™ve used SRF on track for years and never had an issue. Iā€™ve heard others have, tho. Iā€™ve wondered in climate has something to do with it.
 

WItoTX

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Iā€™ve used SRF on track for years and never had an issue. Iā€™ve heard others have, tho. Iā€™ve wondered in climate has something to do with it.
It certainly doesn't seem like a huge issue. However, I ended up at TMO researching, and found the parts needed for under $100. Since it's not critical, I'll probably take care of it this summer.

You are not the only person I've heard never have an issue with it.

I messaged a friend late last night after I couldn't get the dang brakes bled, despite doing it three times. He said pump the clutch until your leg feels like it is going to fall off. "Huh, did you read my text, or are you drunk?" Sure enough, pumped the clutch a ton, and the brakes got significantly stiffer. Going to do one more round of bleeding at the caliper tonight just to make sure all the air is out, but interesting design from Ford for sure!
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