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On flushing the brake system

A

Alfonso Gomez

Guest
I have to flush my brake system because the fluid is dark and contaminated with moisture. It is an 87 Coupe without ABS. I know it has moisture because when the engine heats up (190 - 220) the brake pedal goes to the floor and it will not stop. When it cools down, the brakes start working again.
I plan to use DOT 4 fluid sisnce it has a higher boiling point. What worries me is cleaning out all the old fluid and debris inside the brake system.
I plan to open all bleeder valves with small hoses connected to them and pump the brake pedal until all the fluid is collected in jars. Then I will have to put more fluid (cheap DOT 3) and continue to pump the pedal to get all the dirty fluid out.
Is there a solvent I could use to really clean out the system before I use the DOT 4?
 

c4cruiser

Well-known member
Joined
Feb 22, 2002
Messages
971
Location
Lacey, WA USA
Corvette
87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe
All 1987 Vettes had ABS. Did somebody remove yours??

Simply passing fresh clean fluid thru the brake lines will effectively flush out the old dirty fluid.

The best way to flush the system is with a pressure bleeder. That way you will be able to force fluid thru each line in turn without worrying about creating air pockets if you just leave all of the bleed valves open. Start by using a turkey baster to suck out the old dirty fluid from the master cylinder reservoir. Add fresh fluid and connect the pressure bleeder. Open each bleed valve in turn until clear fluid comes out. Close the bleeder and go to the next caliper.

Another good way to bleed your brakes is to get a set of Speed Bleeders. Not the Russell version but the real SpeedBleeder (www.speedbleeder.com) These simply screw into the caliper in place of the stock bleed valves. They have a spring-loaded check ball in them so when you open the bleeder about a 1/4 to 1/2 turn, simply pressing on the brake pedal will force fluid out and the check ball will close the passage when you release the pedal. Just put a vinyl tube on the valve and put it into a container to catch the old fluid.

Unless you plan on extreme braking like you might see during open track days, a good quality DOT3 fluid will suffice for general street use. Castrol LMA, Ford Motorcraft HD fluid or Valvoline SynPower are all good fluids and available at most parts stores (the Ford fluid can be had at Ford dealers). Figure on a full quart to do a complete flush.
 

Hot Rod Roy

Well-known member
Joined
Jul 6, 2005
Messages
317
Location
Mission Viejo CA
Corvette
Yellow '84 Coupe
Don't let your master cylinder go empty while your flushing your brake lines. It will make your job a lot harder if you get bubbles in the lines. Use the Type 4 to flush the lines, too. It's not that much more expensive, and then you can be sure you aren't mixing 3 and 4 as you bleed the lines. When the fluid coming out of the bleeders is clean, your done! I like the Castrol LMA, too (which I think is DOT 4). That Ford stuff might be okay, but I wouldn't put in MY 'vette!

:w S.T.W.
 

froggy47

Well-known member
Joined
Oct 24, 2002
Messages
1,000
Location
CA
Corvette
Black 1996 LT4 Coupe/ 2004 Z06/Z16
All 1987 Vettes had ABS. Did somebody remove yours??

Simply passing fresh clean fluid thru the brake lines will effectively flush out the old dirty fluid.

The best way to flush the system is with a pressure bleeder. That way you will be able to force fluid thru each line in turn without worrying about creating air pockets if you just leave all of the bleed valves open. Start by using a turkey baster to suck out the old dirty fluid from the master cylinder reservoir. Add fresh fluid and connect the pressure bleeder. Open each bleed valve in turn until clear fluid comes out. Close the bleeder and go to the next caliper.

Another good way to bleed your brakes is to get a set of Speed Bleeders. Not the Russell version but the real SpeedBleeder (www.speedbleeder.com) These simply screw into the caliper in place of the stock bleed valves. They have a spring-loaded check ball in them so when you open the bleeder about a 1/4 to 1/2 turn, simply pressing on the brake pedal will force fluid out and the check ball will close the passage when you release the pedal. Just put a vinyl tube on the valve and put it into a container to catch the old fluid.

Unless you plan on extreme braking like you might see during open track days, a good quality DOT3 fluid will suffice for general street use. Castrol LMA, Ford Motorcraft HD fluid or Valvoline SynPower are all good fluids and available at most parts stores (the Ford fluid can be had at Ford dealers). Figure on a full quart to do a complete flush.

Do what this man said. Dot 3 (I use the Ford stuff)
 

Robertwav1

Well-known member
Joined
Jan 7, 2003
Messages
813
Location
Ocala, Florida
Corvette
1993 Blue
I have to flush my brake system because the fluid is dark and contaminated with moisture. It is an 87 Coupe without ABS. I know it has moisture because when the engine heats up (190 - 220) the brake pedal goes to the floor and it will not stop. When it cools down, the brakes start working again.
I plan to use DOT 4 fluid sisnce it has a higher boiling point. What worries me is cleaning out all the old fluid and debris inside the brake system.
I plan to open all bleeder valves with small hoses connected to them and pump the brake pedal until all the fluid is collected in jars. Then I will have to put more fluid (cheap DOT 3) and continue to pump the pedal to get all the dirty fluid out.
Is there a solvent I could use to really clean out the system before I use the DOT 4?

Sounds like the master cyl is crapping out. Don't ya think you should replace it? Pedal shouldn't go the floor unless the cyl is bypassing. Brake fluid is corrosive and the fact that it is dark in color is a sign that something internal is breaking down. I wouldn't just replace the fluid....I don't think that's gonna help....see what others think?
 

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