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Discussion Starter #1
hey guys, im looking to do some more roadcourse racing and was going to flush the brake system and fill it with DOT 5. Does anyone know if the components have any issues with dot 5? or am i good to go, because once i fill it with 5 i obviously plan to leave it in there permenantly. also any particular brands of fluid i should stick with? thanks
 

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I believe DOT5 is for full on race cars with specific components. Stock is DOT3. I switched to DOT4 after a spongey pedal incident, but make sure to keep the level below the line a little or it may leak under hard braking/fast launches.
 

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It is silicone-based , so you will need to flush your system with alcohol to remove all the old fluid, It will make your peddle spongey. I know a lot of old car collectors use it to stop the brake sys from rusting.
 

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Discussion Starter #4
What about dot 5.1 specifically designed for ABS vehicles - non silicone. Do I still have to flush the system?
 

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Well, if you are considering changing brake fluid you need to do a LOT of research.

As noted above, DOT 5 Silicone-based fluid is NOT appropriate for ABS-equipped cars, and in fact has fallen almost completely out of favor with all performance automotive users. For every good thing about DOT 5 Silicone fluid, there are two bad things, for high performance street/strip/track automotive uses.

Your current choices are:

DOT 3 - the default, works reasonably well, has moderate dry and wet boiling temps, probably adequate unless you are seriously tracking the car and only needs to be changed about every 3-4 years, though feel free to change it more often.

DOT 4 - slightly higher DRY temps than DOT 3, BUT!!! it is worse when wet, meaning that to take any advantage of DOT 4 you need to be flushing and changing your brake fluid every 6-12 months. If you aren't changing that often, use DOT 3.

DOT 5 Silicone - Don't Use!

DOT 5.1 - similar to DOT 4 with more additives yielding higher dry and wet boiling temps, some formulations are stable, and some have the same aging issues as DOT 4. It may allow slightly better performance of very new ABS systems, but this is not a guarantee. Not a lot of experience with this fluid, if you plan to go this route, do lots of research.

As a general rule, changing from DOT 3 to DOT 4 or DOT 5.1 does not REQUIRE a complete flush of the system, just push out the old fluid with the new. HOWEVER, it is a REALLY good idea to do a complete flush. And don't come blaming me if you don't flush and it goes badly...

Changing to or from DOT 5 Silicone REQUIRES a flush with alcohol and checking all the seals, hoses, and other components for compatibility.

One final caveat: Some European cars and accessory manufacturers will say DOT 5 when they mean DOT 5.1. Apparently DOT 5 wasn't ever used much in Europe, so they just say DOT 5, but really mean DOT 5.1. Of course, then some of them DO use DOT 5 Silicone, so you have to check thoroughly whenever you see DOT 5 mentioned.

Good Luck!

FluxPrism
 

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tea84 said:
Flushed it with 5.1 and ran it at pocono raceway. No brake fade. Ran great!
Hmmm, did you happen to have any of that sticky-clutch-at-high-RPM-shifts issue with stock fluid and if so, is it gone with 5.1?
 

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Discussion Starter #8
As a matter af fact I did have that issue before. But only at the drag strip. Ill update once I make a couple runs. But I had no issues on the road course.
 

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tea84 said:
As a matter af fact I did have that issue before. But only at the drag strip.
Yeah well I crank it up to 6K whenever a POS cuts me off. lol
tea84 said:
Ill update once I make a couple runs. But I had no issues on the road course.
The DOT4 helped but not solved it for me so def considering this now, thanks. Reports also appreciated.
 
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