DOT 4 Brake Fluid?
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,625
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From: Cut n Shoot TX
DOT 4 Brake Fluid?
Notice that DOT 4 fluid has a higher boiling point than DOT 3 and is synthetic. Also says it is good in DOT 3 systems. Does that mean it is OK to mix DOT 3 and DOT 4 brake fluid?? 
Le Mans Master
Joined: Apr 2007
Posts: 7,353
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From: Graceland in a Not Correctly Restored Stingray
If it's silicone based, not only should you not mix it with mineral based, you shouldn't even consider it unless you're putting your car in long term storage. Otherwise, you should be OK.
Last edited by TheSkunkWorks; Oct 1, 2007 at 11:26 PM.
Racer
Joined: May 2005
Posts: 436
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From: Stavanger
You can mix dot3, dot4 and dot 5.1. (dot 5.1 is the best)
Dot5 can not be mixed with other fluids, cause it is silicone based. it also is more compressible, and you dont want that in a performance car. (made for long time torage and minimal service, the army use it forexample on some of theyr cars.)
Dot5 can not be mixed with other fluids, cause it is silicone based. it also is more compressible, and you dont want that in a performance car. (made for long time torage and minimal service, the army use it forexample on some of theyr cars.)
Melting Slicks
Joined: May 1999
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From: Moon Township PA
I use the Valvoline Synpower and it mixes readily with standard DOT 3.
Gary
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Synpower is good stuff good for 500 degree boiling. Where DOT 3 is more like 320. Wilwood sells 570 deg. I bought some racing 600 degree. For a laping car of lower speed the higher temp fluids might get you by
Le Mans Master
Joined: Mar 2001
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From: Ann Arbor Michigan
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Safety Car
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From: NorCal
It's been a while, but when I was in charge of brakes and drivetrain for an SCCA national race team, Ford DOT 4 fluid rocked. I wasn't able to get any of the other fluids to work as well, and quit trying after a couple of attempts. Redline was OK, but I had to change it more often and pedal feel definitely was off by the end of a full session. Most of the GT-1 guys swore by the Ford fluid, and those big 'ole cars really needed their brakes! Probably better stuff out there now, but for all around use, it's pretty hard to beat...
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All grades are "synthetics". Only Dot 5 is silicone based and cannot be mixed with the others.
