Newbie with Another Question: Brake Fluid

When picked up my M35A2, the brake pedal felt spongy and went nearly to the floor. The fluid lever in the master cylinder was low and after adding some fluid, the brake pedal felt fine for the entire drive home. (832 miles, but that's another story for later.) The problem is I added "plain" brake fluid DOT 3/4; and now I've discovered that the system is suppose to use silicone DOT 5 (correct?). I need to flush the system; but I got to thinking: I bought this truck from a private party and it has had 3 previous owners since it left the Army. How do I know that the system hasn't been rebuilt at sometime and there is DOT 3/4 brake fluid in it instead of DOT 5? Is there someway to tell the difference (color, smell, taste?). I'd hate to flush the system and put the wrong type of fluid in it.

Also, where do folks go to get DOT 5 silicone brake fluid?

More dumb questions to come. Thanks.

www.sprucemtsurplus.com Has the dot5 in gallons for 30 bucks As long as you flush the system completely it really doesnt matter what you put in, Dot 5 or dot 3, Both of my deuce's have dot 5 in them, when i got the trucks i completely flushed the systems and put dot 5 in them, So that way i know exactly whats in the system.

Plus, dot 5 is a purple-ish color.... The other is red.

dot 3 mixes with water, dot 5 doesn't

Stick with DOT 5 Fluid. If you get the cheap DOT 5 Brake fluid, at least check the year that is was manufactured. Some stuff sits on a shelf for years and may or may not go bad (If it can at least.) I know is very expensive, but Napa Truck Stores have 1 Gallon containers of DOT 5 - Factory Fresh for about $100 - $115. Very Pricey. Stay away from the qt or pt sized containers found at pepboys and the like unless you want to spend a million dollars on brake fluid. You'll need anywhere from 1/2 to 1 gallon (Depending on contamination) to properly flush your system. Highly recommend you get a pressure bleeder. Makes life extremely simple to bleed by yourself.

Gentlemen, thank you.

I'll stick with the DOT 5 since I know there are significant benifits. I'll purchase a gallon from sprucemtsurplus.com and give the system a good flush (which is not a bad idea in any case).

-Russ