i was wondering if u guys know if s5 turbo brake bleeders r the same as s4 braker bleeders?
also is it safe to put in dot-5 brake fluid? and is it any better? thanks!

 

i can type out a whole article, but in short, you MUST flush your entire system, DO NOT mix DOT 5 with DOT 3, DOT 4, or DOT 5.1.
DOT 5 CANNOT be used in ABS systems.

 

Dot 5 and dot 3/4 will NOT mix... Dot 5 doesn't absorb water (its silicone based) and it will not absorb into dot3/4. If you mix it, the two mixtures will seperate in the system and causing uneven braking.

Why?

dot 5 doesn't compress nearly as much as dot 3/4. Whatever residual dot 3/4 is in the brake line will compress before the dot5... this means that when you step on the brakes, the front left tire may lock up, and the front right may not even activate...

sounds like fun huh?

 

btw.. as for the bleeders, IIRC they are different sizes, see my big bolt thread... i think they are listed there

 

so as long i bleed all of the dot-3 brake fluid i can put in dot-5?

 

i believe it has other downsides. i'll write the article out. i just tried to find my other brakes book (i'm looking at the shop manual), but i couldn't. the info is worth looking at nontheless. hold up while i type it out.. sucka !


using DOT 5 Silicone Fluid
DOT 5 silicone fluid does not absorb water and has a very high boiling point. It is noncorrosive to hydraulic system components, and it does not damage paint as does polyglycol fluid. DOT 5 fluid has other characteristics that are not so beneficial.
DOT 5 silicone fluid has a lower specific gravity than polyglycol fluid. If the two types are mixed, they do not blend; the silicone fluid seperates and floats on top of the polyglycol fluid. Therefore, if a customer [or rx7 owner] wants silicone fluid in his vehicle, all the polyglycol fluid must be completely flushed out. The best time to convert to silicone fluid is during a complete brake system overhaul.
Silicone compresses slightly under pressure, which can cause a slightly spongy brake pedal feel. Silicone fluid also attracts and retains air more than polyglycol fluid does, whicj makes brake bleeding harder; it tends to outgas slightly just below its boiling point; and it tends to aerate from prolonged vibration. DOT 5 fluid has other problems with seal wear and water accumulation and seperation in the system. All of these factors mean that DOT 5 silicone fluid should never be used in an ABS.
The best practice is to use a single, high-quality brand of brake fluid of the DOT type specified for a particular vehicle. Avoid mixing fluids whenever possible.

 

you realise how long this will take to rebleed with dot5? The advantages aren't worth the $20 per quart either...

Air gets trapped in silicone pretty easily, so you will have to bleed the entire system 4-5 times to initially get the air out, and then once every 6-12 months.

 

ok i'm convinced i won't put dot-5 fluid in my brakes. thanks everyone for the helpful info!

 

I have to admit, good call!

leave dot 5 for the new cars that "require" $20/qt brake fluid!