hey i took my car into an import service place to have my tranny fluid changed. i wanted them to change my brake fluid w/ the valvoline syn power fluid but the mechanic told me that putting in synthetic brake fluid would cause severe problems with my car. i didnt argue w/ him b/c he seemed pretty knowledgable but isnt this wrong? alot of people are putting in like ATE superblue and valvoline syn power i think and are not experiencing any problems.

 

I have no idea why so many people are scared of synthetics. Then again I also wonder how so many mechanics out there actually have jobs.

 

You might want to find yourself another service department. A lot of comments and misconceptions like that are perpetuated by ignorance. Most people, on almost any subject, tend to think different = worse. Gear and engine oils are a perfect example of this. As long as you're using a proper weight, and a reputable brand, you'll be fine.

 

He's confused, and doesn't understand brake fluid grading. Do not take your car there again!!!

There are several commonly specified grades of brake fluid by the DOT - DOT 3, DOT 4, and DOT 5 are common. 3 and 4 are what's specified by all car manufacturers, are reasonably interchangeable, and those are the specs for ATE and V. Synpower. DOT 5 is silicone-based, NOT synthetic, and THAT is the brake fluid to avoid at all costs - silicone. Never, ever, use DOT 5 in your RX-8.

Additional wrinkle - there's a recently new brake fluid classed as DOT 5.1. 5.1 IS compatible with DOT 3 and DOT 4 brake fluid.

Summary - DOT 3, 4, and 5.1 are OK. DOT 5 is very bad. Silicone (DOT 5) is bad; synthetic DOT 3, 4, or 5.1 is fine.

 

I actually use Valvoline SynPower brake fluid in a number of my other vehicles with no problems whatsoever. SynPower is just a DOT 4 brake fluid with a higher than average boiling point (they don't claim it meets any higher spec).

 

What to the DOT's signify? Do they meausre "thickness" as with oil grades, or something else? And what is the 5 typically used in?

 

DOT 3, 4, and 5.x have successively higher boiling points and varous resistance to moisture. Anti-lock or newer brake systems typically call out the DOT 4 spec. They all pour the same and look pretty much alike. Don't use a grade less than called out. DOT 5 (without the .x) is silicone brake fluid and, technically, can be used in almost any brake system - however, it's incompatible with DOT 3, 4, 5.x and you'd have to flush the system first (not as easy as it sounds because if it's not done 100% thoroughly you literally end up with mush in your brake system). DOT 5 doesn't absorb water so, theoretically, your brake system shouldn't get any corrosion (a good thing). The bad thing is that if any moisture should, somehow get into your brake system (contaminated flush, for example) it would be trapped and contribute to corrosion and/or boil off and create brake fade (a bad thing). Some feel DOT 5 makes their brake pedal mushy. DOT 5 costs more but doesn't take your paint off if you spill it on your car (like the others would).

 

I have used nothing but Valvoline synthetic in all my race cars (RX-7's, RX-8, Miatas) for years and never had a single fluid related problem, including never once having boiled the fluid.

Steven

 

put some Motul Dot 5.1 in today . The pedal now seems to vibrate a little as I apply the brakes . As if there fluid is not lubricating the seals & they are grabbing .
Anyone else had this before ?

 

wow,

you drug up a almost 2 yr old thread.. good job...

btw, still no news.

beers

 

heh - well at least I searched .......

 

Haha...damned if you do, damned if you don't! Welcome to internet forums!

 

I had that feeling at first, but after maybe 2-3 weeks its gone.

I guess its break-in period maybe ?

 

This thread is old but

I think if I were u, I will just tell the owner of the dealership so they can fire him.

cuz obviously that dude doesnt even know the automobile basics. FIRE HIS ***.

 

Ok, as everyone knows, I just replaced all my brake pads a couple of days ago. I bedded the pads (10 stops from 60 mph to 10 mph) TWICE with a 4 hour rest between. Brakes feel smooth with no judder. Only issue is brake pedal feels very soft and I have to push the pedal down quite far now, which means I'm going to have to bleed the brakes, which means I'm going to have to buy some brake fluid.

What would you guys use? Dot4? I never track my car and I drive real conservative, mostly fwys.

What is used by the dealership when they top off my fluids when my car is in for an oil change? Does the dealership use Dot4? Is there an OEM brake fluid for the RX8 and if so, would you guys encourage me to buy it?

If I top off using a different kind of brake fluid (versus the brake fluid that's already in my car), is the mixing of different brake fluids ok (like adding different kinds of engine oil together isn't a big deal)?

 

If it feels softer than before, that means you did NOT bleed your brake lines correctly and theres some air still inside.

Happened to me. when I first bled my lines I didnt put my car off the jacks, I start her up and try, yep, its soft, so I bleed it again, and yep, this time it feels right.

So if u'rs is soft, bleed it again.

 

I wrote that I haven't bleeded yet but I'm going to.

My question was about brake fluid.

 

Yes, brake fluids of the DOT 3 and 4 type are miscible.

...and if you think about it, ALL brake fluids are 'synthetic' unless you fresh squeeze the fluid yourself, from an organically grown Diethylene glycol monoethyl ether tree!


S

 

If your not going to track your car use what is recommended in the manual (DOT3) . Dot 3 & DOT 4 can be mixed without any issue.

 

Use DOT4, DOT3 is fine too. but DOT4 is better so why not ?

and ALL Brake Fluids are *Synthetic* when you think about it.

 

and ALL Brake Fluids are *Synthetic* when you think about it.


hey.....is there an echo in here?


S

 

So are all brake fluids synthetic or not?

Ok i'll go with DOT4. Valvoline Syn Power or ATE TYP 200? I read that ATE TYP 200 is the same as ATE super blue, the only difference is it's amber instead of blue color.

What would you guys purchase for my type of driving?

 

Ahh **** u answered it. wasnt paying attention :P

 

What is *your type of driving*

Any name brand Fluids are good to use.

and yes they're all *somewhat* Synthetic

 

for your use i'd recommend Valvoline Syn Power since they're widely available (any major auto parts chain store should have it) and they're inexpensive ($5 gets you the BIG bottle that'll be more than enough to flush your whole brake system)