Brakes: Brake fluid type

[Bob Beckert]

I have just acquired a lark. In checking the master cylinder [to top it of. But what type of brake fluid is in there. Is there any way to find out if it is type 3 fluid or synthetic fluid. Any ideas on this matter

[mch]

is there any way to speak with previous owner or do you have any receipts that would reference what was used?
Mark

[62champ]

If you have no information on what type of fluid is in the brake system, there is a good bet it is ready for a change. Flush out the old and refill with brand new. Good luck.

[StudeRich]

You can tell by the slipperiness and Odor of real DOT 3 Brake Fluid, probably caused by the glycerin and alcohol, otherwise known as glycol Gliseron in it.

Most Cars you find have DOT 3 or 4, possibly due to the huge COST difference between 3 & 4 vs 5.

The DOT 5 Silicone Fluid has a very different Odor and almost none, very Mild.
Also, most DOT 5 made in the last 20 years is Purple not Yellow/Tan.

[sweetolbob]

Take some dot 3 fluid in a clear container, add some of the fluid in your MC, If they mix it's dot 3/4/5.1. If it makes two layers it's dot 5.

Bob

[E. Davis]

I have just acquired a lark. In checking the master cylinder [to top it of. But what type of brake fluid is in there. Is there any way to find out if it is type 3 fluid or synthetic fluid. Any ideas on this matter

Easiest way is to dip your finger into the fluid and touch a little to your tongue . Type 3 will have a definite acrid taste. Type 5 is usually purple in color, type 3 is clear or slightly amber.

[gjamesk]

While DOT 5 is purple when new, it does lose its color after a while, so don't count on that for identification.

[Jeffry Cassel]

Synthetic fluid is compatible will DOT 3. Use it. It is far less hydroscopic than Walmart fluid so less water, less rust. I use Valvolene synthetic fluid. Flush it really well. Avoid silicne as it softens rubber and is tough on brake light pressure switches. Be sure no cylinders leak. If they do replace them as they are likely beyond honeing

[sweetolbob]

Synthetic fluid is compatible will DOT 3. Use it. It is far less hydroscopic than Walmart fluid so less water, less rust. I use Valvolene synthetic fluid. Flush it really well. Avoid synthetic as it softens rubber and is tough on brake light pressure switches. Be sure no cylinders leak. If they do replace them as they are likely beyond honeing

I'm a bit confused here. Dot 3,4,5.1 fluids are all based on glycol ester technology and 5.0 is silicone. 5.0 is incompatable with all the glycol esters.

I'm not trying to start an argument but all the esters are hydroscopic no matter where they are purchased. Silicone is not. Just trying to avoid any issues with implementing the use these fluids.

Bob

[Frank DuVal]

I'm not trying to start an argument but all the esters are hydroscopic no matter where they are purchased. Silicone is not. Just trying to avoid any issues with implementing the use these fluids.

Yes! aka hygroscopic (tending to absorb moisture from the air).

And what is Walmart fluid? Is it not a DOT 3 or DOT 4? Then it has to meet specifications of that type.

The major problem with brake fluid is the terminology has changed. 30 years ago, when someone mentioned synthetic fluid, they were talking about silicone DOT 5 brake fluid. Now a-days, synthetic is used as a term for non-silicone brake fluid by some manufacturers and brake fluid users, and does refer to silicone DOT 5 by other brake fluid users. So, unless the DOT numbers are being discussed, don't believe you understand what people are talking about!

[JoeHall]

Easiest way is to dip your finger into the fluid and touch a little to your tongue . Type 3 will have a definite acrid taste. Type 5 is usually purple in color, type 3 is clear or slightly amber.

And if the taste test doesn't work for you, try snorting it. If your eyes cross, it's probably DOT 3. LOL

[E. Davis]

Believe me it works. When I was young and worked in a garage/gas station we had to learn little tricks like that because we didn't have time for lab checks on every question. I worked with a guy that could tell you the strength of anti freeze within 5 degrees by tasting it. Couldn't get away with it now days I guess.

[Dwight FitzSimons]

All brake fluid is synthetic, so that term doesn't mean anything.
-Dwight

[Mrs K Corbin]

And if the taste test doesn't work for you, try snorting it. If your eyes cross, it's probably DOT 3. LOL

LOL