Could I recognize Dot5 fluid just from looking at/feeling it?

[elduderino200]

Long story short: I had my brakes serviced a few years ago (2012 or 2013 - cant remember) and in my reservoir when the car went in, was SuperBlue. They called and asked if I had any more of it because they didn't have any and I said no (and they could save me money by not having to buy more), but when I got my car it was filled with blue brake fluid.

I need to do some brake servicing again but I just need to bleed and top off rather than complete flush so I'm worried I'll put in amber-colored Dot4 and in there is Dot5 (which is apparently purple colored) and I'll have a major issue on my hands.

Since they said they had no more SuperBlue and at the time (or right around it) it became "illegal", I'm worried they flushed and put in Dot5. Why would they say they had no more SuperBlue then give me back a reservoir filled with blue fluid?

Is there a way to look/feel the fluid to make sure it's one or the other?

[Audibot]

Your vehicles components are not meant to handle DOT 5, so I sincerely doubt they filled it with DOT 5 without you knowing. If anything, maybe DOT 5.1 or just colored that way because your old fluid stained it. Found the following in a quick search:

1. ALL, and I mean ALL, old DOT 3 or 4 fluid must be removed from
your present brake system. This means disassembling all parts,
including master and slave cylinders, to thoroughly clean them of
old brake fluid with alcohol. DOT 5 does not mix with any other
brake fluid.

2. DOT 5 is composed of smaller molecules, meaning it leaks past
joints in brake line that DOT 3 or DOT 4 won't. You find yourself
tightening everything, and replacing some junctions, in order to
keep the DOT 5 inside your system.

3. While the rubber parts used in today's brakes does not react to
DOT 5, the same cannot be said of the rubber bits used in the systems
of older cars. Some stuff as current as the 1980's will swell up
when exposed to DOT 5. Check with others about your current car and,
if you switch to DOT 5, avoid NOS brake parts that the fluid will
come into contact with. You'll find out soon enough if a part will
work with DOT 5 after installing it on your car.

4. DOT 5 has a propensity to hold air in suspension within itself,
making it very difficult to bleed. Never shake the can, always
pour it out VERY SLOWLY and expect to spend extra time bleeding your
brakes to expel all of the air in the lines.

Can't think of anything else. Once you've switched, you can effectively
kiss corrosion goodbye, as long as ALL of the old fluid is gone and you
never mix DOT 3 or 4 with the DOT 5.



However, since it's silicone-based, you could pipette a bit out and see if it mixes with water. If they mix, it's NOT DOT 5 (maybe DOT 5.1).

[elduderino200]

Thanks!

I figured I was being a worry-wort, I just needed confirmation and for someone to tell me to shut up.

I'll definitely pipe a little bit out and see if it mixes. You're probably right in that they just topped off with some amber-colored Dot 3/4/5.1 they had and it wasn't enough to change the color from blue. It's probably just a tiny bit less blue than it was before.

[Seerlah]

Kind of hard to mix wrong brake fluids when caps say what fluid it takes. Brakes are most important component on a vehicle and is why so many safety concerns revolve around it. With that being said, I run motul 5.1. No real flush but blead lines till clear with new fluid. No issues.