What brake fluid to use

[aany001]

I'm about to start bleeding my brake system and wanna use paint safe brake fluid. Anyone know which one I should use? I've been told dot 5 will do the trick.
Curious what everyone else is using.

[slugo10]

I used dot 5 on my previous 69 Camaro. Worked great and if it leaked it did not hurt the paint. You just have to make sure there is no dot 4 left because they do not mix. I started with all brand new stuff lines, master cylinder, calipers and such.

[dontlifttoshift]

Is it a museum car or will it actually see miles? Any hard use? What kind of brakes are you running?

Not all caliper or master cylinder seals are compatible with DOT 5 silicone fluid. Replacing 4 calipers and a master cylinder and flushing all of the lines is not fun.

There is moisture in any brake system, with DOT3, 4, or 5.1 the moisture is is absorbed by the fluid and pretty evenly distributed. With DOT 5 silicone, moisture is not absorbed an it will puddle together. If the moisture happens to puddle near a caliper and it gets hot enough it turns to steam, now you have no pedal. I have never actually heard of that happening but it is feasible.

DOT5 silicone fluid is compressible, you will never get a great pedal. You can get an okay pedal, but it will never be great.

As already mentioned, it _will not_ mix with regular brake fluid. I can't stress that enough.

The only upside is that it doesn't eat paint. Neither will DOT 3, 4, or 5.1 as long as you clean up any spills.

[aany001]

I have all C6 Z06 front and rear with C5 master and booster. It's gonna be a street car that will be driven occasionally. Might see a track event but doubt it. Everything is painted a detailed and don't wanna mess anything up. I'm just going to run the regular stuff and wet everything down to help neutralize the damaging effects of the brake fluid.

[Shiner]

I doubt one can feel the difference in pedal between DOT 5 and 3/4. I plan on flushing and going with Dot5

[Apogee]

Originally Posted by aany001

I have all C6 Z06 front and rear with C5 master and booster. It's gonna be a street car that will be driven occasionally. Might see a track event but doubt it. Everything is painted a detailed and don't wanna mess anything up. I'm just going to run the regular stuff and wet everything down to help neutralize the damaging effects of the brake fluid.

I use isopropyl alcohol in a spray bottle for cleanup of DOT3/4/5.1 glycol based brake fluids. It's cheap and works great.

As for the difference in pedal feel between the glycol and silicone based fluids, I can notice a difference, especially on motorcycles where you're using a hand brake. Take a container of DOT5 and shake it up, then note how long it takes for all of the tiny champagne bubbles to dissipate...that's what's happening in your brake system. Do the same with DOT3/4/5.1 and you'll find that the bubbles dissipate almost immediately. With that said, to each his own. The military is the largest single user of DOT5 silicone based brake fluid due to the higher levels of lubricity at low temperatures, but they've been looking for a better alternative for years due to it being immiscible with water as noted above.

[aany001]

Tobin I ended up going with the dot3 fluid and was cautious about keeping everything wet with water and it worked out well. After everything was bled and noticed I had no power assist due to a defective brake booster. It came out of a wrecked C5 and I guess it was damaged cause it wouldn't hold any vacuum. I managed to re and re the the booster without disconnecting any of the brake lines. Once again I gotta thank you for all the helpful tips and info to make my brake system work flawless.
Thanks
Steve