Contour Enthusiasts Group Archives Forums Modifications Brakes Brake Fluid--Can regular and synthetic mix?

If I have regular mineral-based DOT 3 fluid in my reservoir, can I top it off with Valvoline Synth-Power (DOT 3 and 4) or something similar? Or am I stuck with the old DOT 3 until I have time to flush the whole system?

Dino and Silcone brake fluids can not be mix. That being said, the Valvoline Syn-Power is a synthetic and you can use it just fine. If you have to toping off your brake fluid it probably means your pads are just about shot. You should probably have them checked. I would also suggest while you are at it to flush your whole braking system and put in ATE TYP200 or ATE SUPER BLUE. They are the same formula's in different colors. $15 will get you a litre and that is more than enough to flush the whole system and the clutch, if you have a manual!

-Andy

Thanks, Andy.

I'm getting ready to change discs/pads all around. My plan, right now, is to do the rear axle tonight. The rears are at kind of a critical wear point, and I have 2 weeks until my next Autox. That should be enough time to break in the rears. (I hope.)

For the fronts, I'm going to wait until after this autox season is over, and at that time, I plan to switch to new fluid.

I'm installing BAT premium rotors with Mintex A/F pads, which have no bed-in procedure dictated except "try not to do hard braking for the first 200 miles."

If any of this sounds stupid or wrong-headed, please say so.

If you are going to Auto-X I'd go with a pad a little better adapted for high heat like the 1144, KVR, or even EBC Green/Red Stuff pads!

As for bedding pads, soft pads like the AF's don't take long to bed and just go easy on the braking because you could warp new rotors in the first few hundred miles. If you get a harder compound like, CF it can take up to 1000 miles before they even start to bed well!

-Andy

If in doubt, read the label. Valvoline does mix with factory fluid just fine.

I suspect that you may be confusing synthetic brake fluid with silicon brake fluid. Silicon brake fluid (DOT 5) is not compatible with conventional DOT 3 or DOT 4 fluid and should NEVER be mixed.

I know of no DOT 3 or DOT 4 fluid that is not fully mixable with any other DOT 3 or DOT 4 fluid. I understand that such mixibility is part of the DOT standard.

I'm not confused about silicon vs synthetic. But I am often confused.

Hey Jim does ford still sell the Heavy Duty DOT 3?

IIRC that stuff was all the rage with IT racers because of its high boiling point.

Check this awesome brake fluid page out!

http://www.shotimes.com/SHO3brakefluid.html

-Andy

Great link! Thanks.

Hmmm. I didn't have to crack open that Valvoline when I did my rears. I think it will going back to Autozone along with that rear caliper tool.

Originally posted by TedS:

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Hey Jim does ford still sell the Heavy Duty DOT 3?

IIRC that stuff was all the rage with IT racers because of its high boiling point.

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Yes, Ford still sells a Heavy Duty Dot 3 fluid. It now is packaged in plastic 12 oz bottles with the Motorcraft label instead of metal 16 oz cans with the Ford label. It is still 550 degree dry boiling point fluid. The wet boiling point is not very high though. That is part of the reason that I use Valvoline. It has a much higher wet boiling point. I still change it every year.

yeah that is the downside to the ford fluid... but I know some ITA, ITB and ITS racers who love the stuff... of course they change their fluid after every event (Several times a year).

I have been using Valvoline as well and am pleased with it.