Brake Flush Methods

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ConfederateTyrant

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I have read up on most of the previous post about flushing the brake system. My car is 11 years old, and I assure everyone that the fluid has never been touched. I'm a big do-it-yourselfer and would like any methods to help me do this 100% correctly.

I have heard that the old way of bleeding the brakes, via pressing the pedal and opening the bleeder screw will cause damage to the master cylinder, any truth to this?

Are the "one-man" bleeders effective for this method? Where could I get one of those for a decent price?
 
Get a Mity-Vac. Just about any auto parts store should have them. I use mine all the time on the cars and the bikes. I would soak the bleeder screws with penetrant for a bit before you try and crack them open, and use a bit of sealant around the bleed screw threads so you don't suck air through them (I use Permatex Hi-Tack only because it's what my other friends use- it works). I have heard others use grease.
 
If it is 11 years old and never been touched, you would accomplish a lot more by replacing the aged, worn rubber parts. Seals slowly wear out with the movement of the piston. Boots just get old and lose their elasticity and no longer do a good job of keeping out moisture and grit. Changing brake fluid does nothing to protect the section of the piston between the boot and seal where rust often starts. I really doubt if it even does a whole lot to displace the old fluid in the narrow annular space between the inner part of the piston and caliper bore. I would let it go until your next pad change and then rebuild/replace the calipers getting rid of all the old fluid and accumulated dirt and moisture. Don't confuse replacing the fluid with real preventative maintenance. It isn't even a good start. You would think if old fluid is the problem many here think it is that you would have boiled yours long ago.
 
If you are flushing the brake system every 11 years, why not just go the old school route? You don't have to have a special tool for every single job. (Doing it the "old-fashioned" way once or twice is a good learning experience too.)
 
My other post + ------> I agree with labman. Preventative maintenance has to be preventative! (Bleeding/flushing at this stage probably wouldn't hurt anything though.)
 
'Tyrant, although others here would probably disagree, if you're going to change your brake fluid in that car, you might want to stick with a "standard" DOT3/4 rather than something like Valvoline's Synpower.

Synpower is supposedly somehow more "synthetic" than other brake fluids (even though all brake fluids are an engineered fluid), and it has caused leaks in several older vehicles that I've worked on, both Japanese and American made. Replacing the Synpower with a "cheapie" fluid like Pyrol fixed the problem.

Definitely get yourself a MityVac.

FWIW, my experience only....
 
I did not plan on using any special brake fluid, just the Super Tech DOT 3 fluid. I google searched MityVac, got to the website, and see different ones, there are pressure bleeders and assemblies that attach to the master cylinder and build pressure to force it out. Which do you guys recommend?

Johnsmith, I am not going to flush it every 11 years, I just learned about it recently and decided to give it a try. I have only had ownership for 4 years, before that, my grandparents and my brother, it was very well cared for, but as I read, Ford has just recently put out recommendations for brake fluid flushing. I figured I'd flush it one good time, and start a routine of flushing every couple of years.

By the way, the brakes work absolutely wonderful, but that may be due to my coasting to stops instead of slamming on the pedal.
 
Speed Bleeders will work well if you plan to do regular flushing. I got a set from the local Summit Racing (Russell brand) for $8 or $9 each. I have seen similar products on the rack at chain parts stores.

I put a 4x4 block of wood under the brake pedal to avoid the master cylinder damage you asked about. I don't know if it makes a difference or not, but the theory is to avoid piston travel outside the range of normal braking. Some people say the extra travel could damage seals.
 
Get a vacuum pump and use it to totally flush the old fluid out from the wheel cylinders/calipers. You'll find that the vacuum pump has many uses in the car and on your lawn toys. The only way to do a proper job, IMO.
 
You might try a gravity bleed. I've had some success with this method. Fords are more prone to gravity bleed than others IMO.

Just open the master cyl then open a valve and monitor.
 
ConfederateTyrant, the primary reason why brake fluid should be changed out is because brake fluid is hygroscopic. That means that brake fluid absorbs water. The water lowers the boiling point of the fluid.

You might not notice it on a trip to the corner drug store, but if your brakes are called upon to do some serious stopping, you do not want to lose the brakes because the fluid is boiling. And it doesn't take much water to lower the boiling point dangerously--just a few percent of water and you are in trouble. A lot of techs in the industry recommend changing the brake fluid out every couple of years for this reason.

You might want to research the lazy man's way of brake bleeding--gravity bleeding. Take a piece of tubing with one end immersed in brake fluid with the other end attached to a bleeder nipple. Open the nipple about 1.5 to 2 turns. Do this on each wheel. Then leave all four tubes to drip for a few hours, checking the master cylinder reservoir every now and the to insure the it isn't running dry. About a quart of fluid should be enough to purge and flush your system. Don't forget to tighten the nipples before removing the tubes when you are done. Of course don't overlook putting the reservoir cap back on either.

By the way, if you decide to use some sort of pressure or vacuum bleeding, check the procedure for your particular car in a shop manual. You may need to find the metering valve and lock it open temporarily (note: not all cars have a metering valve).
 
I often use a one-man method where I slip on a tube and crack open the bleeder just a bit and pump away at the pedal. There's enough resistance at the bleeder so it slurps back very little fluid on the release stroke.
 
I'm thinking of getting a Motive Brake Bleeder, http://www.motiveproducts.com/02bleeders.html, has anyone had any experience with these?

It appears to clamp onto the master cylinder, pour in two quarts of fresh brake fluid, then you pressurize it by hand pumping it, then open each bleeder screw one at a time until fresh fluid flows out.

Vizvo, I do not believe there is a metering valve on my car, where would I be able to find a procedure for bleeding?
 
ConfederateTyrant, the only cars which might have a metering valve, are cars with front disc and rear drum brakes. The metering valve slightly delays the full application of the front brakes until the rear shoes start to contact the drums. On cars with FWD, the manufacturers' trend for a number of years has been to eliminate the metering valve. This trend is because of the physics of stopping a FWD vehicle limits the usefulness of a metering valve. Some FWD drive vehicles have one, some don't.

If you try to pressure bleed a car with a metering valve, you might not be able to effectively pressure (or vacuum) bleed the front brakes. Metering valves are designed with an external shaft which can be pushed in and secured with a clamp or strap while the bleeding procedure takes place.

Sometimes the metering valve is included as part of a combination valve which might also contain a proportioning valve and the brake warning switch. The metering valve will always be located between the master cylinder and the lines which feed the front and rear brakes.

The shop manual for your car would have this information. Or maybe Haynes or Chilton. Or do a Google search. Or if you can't find the information, post the year, make, and model of your car and we can look it up for you.

The metering valve is of no concern if you are gravity bleeding or manually bleeding by pumping the brake pedal. You can ignore it in these cases.
 
Vizvo, my car is a 1995 Mercury Grand Marquis, 4 wheel disc brakes. I'll check my Hayne's manual when I get home, though for some reason I remember only seeing a section for 88-91 models that had a metering valve.

Now I am hearing people say to go the "old fasion" way by pressurizing with the brake pedal and opening the bleeder screw, is the rumor of damaging the master cylinder untrue?

I have no problem with that way, I can get someone to press and hold the brakes while I bleed them. I want this car to last me many more years, so I owe it to change the brake fluid.
 
Ok. Yep, it's very doubtful that a car with 4 wheel disc brakes would have a metering valve. I think you can safely ignore the remote possibility.

You can't hurt the master cylinder by pumping the pedal. If you see any leakage out of the rear of the master cylinder, that is because the rear seal has gone bad on its piston. It isn't caused by pumping the pedal. So don't worry; pump away without fear.
 
Alright, if that's the case then I will pump away, or at least get my girlfriend to hold the pedal while I brake the bleeders. I watched someone in my Autotech class in high school do this, some gunky stuff came out of his brake lines. Never occured to me to give it a shot.

Thanks for all the advice.
 
Pumping the MC does frequently ruin it. On an older car, some rough crud may have built up in the far end of the bore where the piston hasn't been in years. The block of wood trick should work.

It is very common for the MC to fail right after other work requiring bleeding the brakes. The piston is pushed deep into the bore and junk there tears the old rubber.

Boiling brake fluid is very unusual. A single hard stop would NEVER cause it. In most cases, if the brakes are abused, the lining will over heat leading to a high, hard pedal long before the fluid boils.
 
Hey Labman, I hear what you're saying. And I know you have the experience to make a good judgment call on the vehicles under your care.

My own perspective is that as safety issue, it is not worth trying to squeeze more life out of an old ailing master cylinder. If I suspect that pumping the brakes hard is going to cause the master cylinder to fail, then it's time to replace the master cylinder.

Same way with brake fluid. My own philosophy is that master cylinders and brake fluid are both cheap, while the cost of brake failure could be dear.
 
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