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Brake pedal to the floor after 4 laps.
#1631686
14/04/2019 16:45
14/04/2019 16:45
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Joined: Nov 2006
Posts: 1,580 Melbourne, Australia
Scuderia
OP
My life on the forum
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OP
My life on the forum
Joined: Nov 2006
Posts: 1,580
Melbourne, Australia
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Took my Coupe to "The Bend", South Australia. What a fantastic facility! More to the point, brake pedal went to the floor after about 3-4 laps on my second run. My question is, can this be something other than the fluid? I haven't done anything different from the previous 4 track events, the only variable is the circuit, which I must admit is hard on brakes but still, it seems unlikely.
Brakes are standard Brembos with Winmax W5 race pads and super dot 4 brake fluid.
First time out I noticed the discs were glazed, noisy LF, a little vibration, nothing too concerning and good stopping power. I tip toed around for the first run learning the circuit, it was my first time out. I decided to try to push the brakes hard on the second run to see if they would come right - and they did, no noise or vibration, good stopping power so I then pushed on and set my fastest 2 laps and by the 3rd or 4th lap the pedal went to the floor all of a sudden. I still felt I was fairly easy on the brakes leaving a lot of margin.
It took 3-4 pumps to get any pedal and then when it came back it was very uneven, pulling to the left, even with the pedal very low the ABS was interrupting, I assume for one of the rears. Let the brakes cool, pedal came back, tried bleeding the brakes, no air. All seems fine again. 3rd run I took it easy for 3-4 laps without trouble, then a few hard laps the pedal went again, this time I continued slowly and the pedal came back up, basically if I was gentle on the brakes they were OK.
Any thoughts?
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Re: Brake pedal to the floor after 4 laps.
[Re: Scuderia]
#1631688
14/04/2019 19:29
14/04/2019 19:29
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Joined: Jul 2007
Posts: 629 Bulgaria
french_coupe
Club member 773
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Club member 773
Enjoying the ride
Joined: Jul 2007
Posts: 629
Bulgaria
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Sounds like a fluid problem. Do you use high temp fluid and change it from time to time? If there was no air and no fluid loss then it cannot be anything else.
lost in space
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Re: Brake pedal to the floor after 4 laps.
[Re: Scuderia]
#1631689
14/04/2019 20:28
14/04/2019 20:28
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Joined: Oct 2008
Posts: 6,783 In the coupe.
magooagain
Club Member 259
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Club Member 259
Forum is my life
Joined: Oct 2008
Posts: 6,783
In the coupe.
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It's easy to boil standard brake fluid in a track scenario. High temp fluid is the only way to go.
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Re: Brake pedal to the floor after 4 laps.
[Re: Nigel]
#1631699
15/04/2019 09:54
15/04/2019 09:54
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Joined: Dec 2005
Posts: 584 Guildford
wink
Club member 1453
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Club member 1453
Enjoying the ride
Joined: Dec 2005
Posts: 584
Guildford
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How old is the Dot 4 fluid? It is hygroscopic, so you may have experienced the water content of the brake fluid boiling in the calipers, which will give the "pedal to the floor" effect.
Before changing any of the hardware, I'd try a fluid change. Make sure you use a top-quality fluid from a household name brand - eg Castrol SRF - there are lots of no-brand brake fluids that have a considerably lower heat range than some of the top-grade stuff +1 old fluid boils at much reduced temperature
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Re: Brake pedal to the floor after 4 laps.
[Re: Scuderia]
#1631706
15/04/2019 15:20
15/04/2019 15:20
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Joined: Jun 2007
Posts: 1,034 Carlisle
Rob40
Club Member 1717
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Club Member 1717
Enjoying the ride
Joined: Jun 2007
Posts: 1,034
Carlisle
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Are you using braided brake hoses? Old OE rubber ones can expand easily under heat and pressure.
This is how it should have come out of Torino!
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Re: Brake pedal to the floor after 4 laps.
[Re: Scuderia]
#1631755
16/04/2019 19:46
16/04/2019 19:46
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Joined: Oct 2010
Posts: 549 Bulgaria
Ferrarist
Enjoying the ride
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Enjoying the ride
Joined: Oct 2010
Posts: 549
Bulgaria
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Had similar situation 4-5 years ago........boiled brake fluid.....
20VT - Alfa 156 2.0 - Alfa 156 Mid-Engined RWD - Locost 20VT
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