superdave269

I just finished putting on new front Hawk HPS pads on my 92 Vert. I put them on the back a couple of weeks ago. I do seen improvement, but I also noticed the brake fluid looks black. I guess I need to change it. Car is new to me so I have no way of knowing when it was done last or ever for that matter. Can I get away with just changing whats in the master cylinder or do I really need to flash the system. Why did it turn black anyway, moisture or over heated?

1986coupe

When brake fluid is black it is time to flush the system. Not a big deal to do. Just get it done then you won't have to worry. Flush the fluid annually and you won't have a problem.

caddyboy84

Be careful, my fluid was black when I bought my car too, but remember that old fluid sometimes holds a part together. When I changed it and bled all 4 corners, I blew the rear seal on the master I knew the risk and wound up losing and going for a master.

JrRifleCoach

Ya think?

Brake fluid (DOT3) is clear with an amber tint. It loves to absorb water. The more water, the less effective your brakes become. Because water boils and creates air, which compresses, rather than being a fluid (solid) and the brakes become spongy. Other fluids like synthetics are less prone to attract water, but some say the braking performance is not as good as DOT3.

IMHO the car was designed with DOT3 so why bother changing. I bleed the entire system once a year and siphon/refill the reservoir mid-year. Or when the fluid starts to "cloud" in the reservoir. If you keep your fluid clean you'll be able to see the cloud I'm referring to. (Most mfgrs recommend changing the brake fluid every two years)

It turns black as the seals and rubber hoses start to deteriorate with age.

When members here post those marvelous pictures of their BEAUTIFUL engine compartments, I shudder when the brake fluid is BLACK as TAR!!

caddyboy84

I keep all fluids fresh on my cars, even the power steering fluid. It's unfortunate that my master went but now everything is new and fresh. My brake fluid was like syrup when I got the car. You gotta be careful changing old tranny fluid too, you can lose the tranny.

superdave269

That makes sense to me.
Wish me luck. Believe me that won't be the worst thing to happen to me..

superdave269

Now you got me wondering why the seals would blow because of new fluid. Can anyone explian what would cause that?

caddyboy84

Fresh fluid washes out the sludge that helps the seals SEAL

93Rubie

You would not need the sludge to seal if you properly maintained the braking system. I do a complete system flush once every two years and a drain and fill on the off years.

I do the same on the clutch hydraulic system.

NEVER use DOT 5 Silicone based brake fluid on any ABS equipped Corvette which is 86 and up.

Brakes are probably the most neglected part of any car, why, I'm not quite sure. Also, a place where people cheap out on...again not quite sure why? They can afford that flowmaster exhuast system, beer, cigarettes, and such but want the cheap $20 pads and $40 rotors. You'd think brakes might be important!!!

QZRBLU

Dave,
Most likely cause of the seal failure was bleeding the brakes by pumping the brake pedal. If the pedal is pushed to the floor(as in manual bleeding) the seals travel across portions of the master cylinder bore that are never used and if there are any deposits in there, they cut the seal. Happens a lot on motorcycles if a vacuum or pressure bleeder is not used.
You should only depress the pedal half of the total travel when bleeding to help prevent seal damage. I use a vacuum bleeder on mine and flush the system every 2-3 years. I would flush it every 2 years in a wet climate.

Mick

JrRifleCoach

Maybe we should bottle this "sludge" and keep for a leaky day?

383vett

Good explanation

desertmike1

Pumping the brake peddle....kind of risky

Ive been using a Mighty Vac for years, with good resuilts.

caddyboy84

Let me try and explain this better. Over time when fluids are NOT changed, the fluids start to get thick with build-up and contaminants from heat and wear. The fluid is then not able to do it's job properly . In turn, the seals and gasgets get used to the thicker fluids almost like radiator sealers help seal the system. When the fluid is finally changed, the thinner, fresh fluid can easily push past seals and gasgets, especially under pressure. If you change and maintain the fluids, the seals and gasgets wont become compromised by contaminants and will remain plyable while in contact with fluids that are clean and of the proper consistancy. Thats why changing very old tranny fluid can bring apon a front seal leak or worse and the same with brake seals. The logic of bleeding brakes causing leaks is crazy, based on that belief you better never have to slam on the brakes in an effort to stop for an emergency at high speed, you'll blow your seals , RIDICULOUS! Allowing any fluids in any machine to out-live it's life expectancy compromises the integraty of that fluid controlled system and all the parts involved. Heat starts to turn the fluid black, although rubber hoses can add to the black color. Based on the belief that black fluid color is cause by the seals and hoses breaking down, once the fluid is thick and black all the seals and hoses shoud just fall apart and burst.

caddyboy84

Whats you're saying is very true, you have to maintain all fluid controlled systems and then any build-up or "sludge" won't have the chance to become a property of the system. I work on million dollar pieces of equipment every day and was sent to school to perform my maintenance work, ask any instructor and he'll say "clean fluid is the life-blood of the machine".

rithsleeper

Original question: what color should my brake fluid be?
correct answer: blue

(If you use the good stuff super blue)

Sometimes i get a second look from tech when they see that

pmihaltian

Invest in a good pressure bleeder and you can do this yourself every two years. Once you are familiar with the process, it takes about half an hour to totally flush your braking system.

caddyboy84

Or clear. I change my fluid with a turkey baster when it begins to get cloudy and use DOT synthetic 3&4.

c4cruiser

It really is a good idea to flush the brake fluid every coupe of years on a street-driven car. If you use the car for things like autocross and track days, it's a good idea to flush the fluid every season at a minimum. People that do a number of track days each year will typically do a fluid flush prior to each event.

As mentioned, most brake fluid has a slightly amber color to it and is nearly transparent.

One thing that doesn't get really flushed in a DIY process is the ABS system. To flush the system properly requires a scan tool like the GM Tech-1 with the appropriate brake module that will energize the ABS pump. The fluid in the ABS system is flushed by opening a bleed screw in the ABS unit itself. It's a messy job as there is nowhere for the old fluid to really go except into the well behind the driver's seat.

caddyboy84

You have me wondering now.......I redid my whole system, master, pads, fluid ect. I didn't bleed out my ABS pump, is there enough fluid in there to compromise the system? and.....Will the fluid in there eventually be pumped into the rest of the system, so when I change the fluid in the master, over time the ABS fluid will be freshened?