Dot 5 Brake Fluid... Is it ok?

casualdreamer

Registered
Well, I am finally getting around to putting on my steel braided lines. I know that the Busa take Dot 4 oil but couldn't find any to save my life. All everyone has is Dot 5. Is this ok? It has a picture of a motorcyle on the bottle. I asked the worker at Autozone was this ok and they said it would work. If I can get the ok from you guys here. I will be draining and removing the old lines tonight and then placing the braided lines on. Also does the clutch run off the same kind of fluid or is it completely different. Can't wait..:bowdown:.
 
Yes it is ok to use for both the brakes and the clutch line.

Just remember to not mix Dot 4 with the Dot 5.
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DOT 5 is fine, but you need to not mix between 4 and 5.
 
You can change from dot 4 to 5 by flushing your brake/clutch with rubbing alcohol then dot 5. The alcohol will act like a mild solvent to remove the dot 4 reliably from the system. Otherwise you need to start with all new components as dot 4 and dot 5 will turn to silicone sludge in your lines and eat anything that can be corroded (ie steel/aluminum). I did this swap on my 69 nova and I didn't get enough alcohol through the wheel cylinders in the rear drums and the stuff ate through immediately (like within a week). I wound up flushing the whole system again with dot 5 and have had no problems sense. Dot5 is cool because it doesn't absorb water so your brake feel and performance stays more consistent.
 
I believe dot 5.1 is dot 4 compatible so you could look for that too, but it is pricey (I think I have seen it around here for $20+ per quart)
 
Unless you dismantle all the fluid handling components and clean them, it is probably better to stick with DOT 4.

For new fluid in a new system, DOT 5.

Linky

Bruce Anderson
 
He explains it nicely and that is another thing I forgot, DOT 5 takes an eternity to bleed properly.
 
Yea I am flushing the whole system and running new lines. So the Dot 5 will be ok. Time is not an issue. I just wasn't sure if it was ok to run DOT 5... Awesome. Wish me luck. Tomorrow, I officially run steel lines. Can't wait to feel the difference. Heard nothing but good word.
 
Unless your doing alot of track days and ALOT of heavy braking I would stick with the DOT4. Mixing the 2 types of fluid will swell and corrode all the rubber seals in the master cylinders and brake calipers. I use dot 4 on mine and have stainless braided lines. I also drag race it and I am slowing down from 140+ mph passes and the brakes feel just as good now as they did a year ago when I changed the lines.
 
dot 5 is silicone based, dot 3 and 4 are based on propylene glycol. don't mix, ever.
 
DOT 5.1 FTW. It is a glycol based fluid so it will last longer as where silicone based fluid requires more maintanence.
 
Autozone sells Dot 4 fluid around here. I just bought 2 bottles of Prestone synthetic Dot 4 part# AS-800P.
They also had Valvoline in 12oz and 32 oz bottles that are dot3/dot4 compatable..
 
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