Brakes: Best Brake Fluid

[cdevan]

As referenced in the Shop Manual for 1955 Passenger Cars, heavy-duty brake fluid is "Lockheed No. 21-B." What is the best or preferred heavy duty brake fluid used by Studebaker owners for 1955-57 Cars?

[63 R2 Hawk]

Opinions will vary greatly. If someone has filled your brake system with silicone (DOT 5) fluid, you need to stick with that type unless you wish to completely flush and rebuild your entire brake system. If an older glycol (alcohol) based fluid has been used, it should be compatable with any modern DOT 3/4 fluid. Never mix silicon and glycol fluids, even in small amounts. It is highly likely that the elastomer brake parts in your car are not original but replaced with newer, improved rubber components that should work with newer, improved fluids. It's always a good idea to completely bleed the system periodically, even if the fluid just needs topping off. I'm sure other opinions will be forthcoming.

[cdevan]

Thanks for the information. Is there a way to tell what type of brake fluid you are running: silicone or glycol?

[Gunslinger]

Silicone brake fluid is purplish in color.

Another way to test it...drip some on your car's paint...silicone won't hurt it...glycol based will dissolve it. Please don't do that!!! Just kidding but that will happen!

[63 R2 Hawk]

There are a number of websites on this subject, here's one of many.

http://adlersantiqueautos.com/articles/brake1.html

[Skip Lackie]

Unless you are replacing all of your car's hydraulic brake parts (or your car has been converted to DOT-5 silicone fluid), you can use any modern good-quality DOT-3 brake fluid.

[RadioRoy]

I like DOT 4 better than dOT-3. The story is that DOT-4 is not hygroscopic like DOT -3. That means it will not suck moisture out of teh air like DOT-3 will do.

[rockne10]

The story is that DOT-4 is not hygroscopic like DOT -3.

Even a sealed hydraulic system will, at some point, accrue some moisture, even if it is just from relative air humidity. In a hygroscopic fluid this moisture will evenly disperse. In non-hygroscopic it will accumulate in pockets where it has the ability to freeze, or initiate internal oxidation.
Evenly dispersed in a hygroscopic fluid, it will take some greater time for the moisture percentage to initiate rusting from the inside out. It will eventually happen; hence the recommendation to fully flush and fill your DOT3 fluid. The manual for our new trucks recommends every 20,000 miles! WHO DOES THAT?

[52 Ragtop]

I rum silicone in my 52, and DOT 4 in the Avanti. I've never replaced the brake light switch as others have indicated that silicone fluid makes them go bad. But, the 52 is on a brass T and comes in from the top, so maybe that's why it's lasted. Either way, it's best to flush your whole system, and check all the steel lines, and check the dates on the brake hose's!
According to Raybesteos, brake hoses should be replaced every 3-5 years. I personally think that is to sell more brake hose, AND keep them out of court!
I have check some of the brake hose for sale at the swap meets, the newest I found was 2008. I quit buying new brake hose when the last 20 I bought was already 3 years old. I now crimp my own, and pressure check them to 3200 PSI for 25 seconds. DOT standards is 1500 PSI for 25 seconds. Brake hose has been dated since at least 1987, the manufacturer symbols and an easily readable date must be printed on the hose a minimum of every 6-8 inches.
If you buy new brake hose, be sure to check the dates on the hose! The last 100 feet of hose I bought is dated 2-20-2012, I do not crimp them until I sell them.

Jim

[rrausch]

.........hence the recommendation to fully flush and fill your DOT3 fluid. The manual for our new trucks recommends every 20,000 miles! WHO DOES THAT?

I flush the brakes on all my cars and trucks once a year. I installed Speedbleeders on all my wheel cylinders, so one person can easily bleed the brakes. It's really not a time-consuming problem.

[Blue 15G]

Regardless of whether your car has DOT 3 or DOT 5 fluid in it, just buy a name-brand fluid of the correct type and you'll be fine. Years ago some gyp stores used to sell off-brand brake fluid with a lower boiling point but I doubt that you could even find that stuff anymore anywhere.

Dave Bonn
'54 Champion Starliner

[Paul Keller]

Agree w/ above - I use Dot 4 (compatible w/ Dot 3, but has a bit higher boiling point). NEVER mix Dot 3 or 4 with silicone Dot 5. Bleed out all fluid once per year (after replacing all components and brake lines, i bled the the system one and one half years later - Noticable rust!) As noted, w/ speed bleeders (like Russells brand) the job is easy, quick and will save a lot of maintenance laster on.
Paul TK