Dot five brake fluid

Norm reynolds · #1 03-31-2015, 01:36 AM

I have a question
A good friend of my has 1966 vette that's been restore ten years
One of the brake calipers started leaking so got a replacement
Now the problem I want to use dot 5 brake fluid just because this car sits
More that on the road He was told if there is one drop of dot 3 will turn the dot
5 in to jelly am WORNG in to try to use dot 5

**luzl78** · #2 03-31-2015, 02:21 AM

I would stay with dot 3

**Lynn** · #3 03-31-2015, 03:35 AM

I would not even consider changing over an assembled existing system. Dot 3 and dot 5 are not compatible. Don't know about one drop turning it to jelly, but does that really matter? How are you going to remove every bit of the dot 3?

The only time I considered dot 5 was when I was putting my car back together after rebuilding EVERY part of the brake system and replacing the lines with stainless. I know some restorers swear by the dot 5 because if you spill a bit, it won't remove paint like dot 3.

I chose the 3 anyway. I am a firm believer that brake fluid needs to be flushed / replaced every 3 or 4 years regardless of whether the car is driven daily or only occasionally. It is a maintenance requirement, just like changing oil.

**njsteve** · #4 03-31-2015, 11:24 AM

It doesn't turn to jelly if mixed. But they are not compatible. Only put in Dot 5 if it is a new fresh system that has not been filled yet with Dot 3. X2 on the frequent flushing. Dot 5 will go bad over time - when I flushed the Dot 5 in Charger a few years ago it had turned dark yellow from the original purple color. It was 5 years old at the time.

Just over the weekend I looked at the original Dot 3 fluid in our 2001 WS6 Trans Am and noticed that the fluid had turned a dark green. NASTY! I suctioned out the reservoir and refilled it with Dot 3. I will be flushing the entire system in the next week or so to get rid of the rest.

I have used Dot 5 in some of my cars - especially the Mopars since everything is body color under the hood and really hard to repaint if damaged by brake fluid. Dot 5 doesn't hurt paint.

Norm reynolds · #5 03-31-2015, 11:53 AM

Thanks every one I guess I will stick with dot 3 for now. two years ago I did a total flush
This car does sir a lot

L78steve · #6 04-01-2015, 10:47 PM

Dot 3 obsorbs moisture. Silicone fluids do not. If you use Dot 3 and you change the dot 3 fluid in the 2 year period as required you will remove the moisture with it. If you use silicone fluids, since they do not absorb moisture you will not be removing the moisture in the system when the silicone fluid is changed.
Remember moisture will get in the brake system reguardless of which type of fluid you use.