seattle_sun

I have been using the Motive to bleed my brakes. I usually do the recommended way by filling the bottle with brake fluid.

I have been reading that some guys are not putting any brake fluid in the container and just using the motive to pressurize and push the brake fluid through.

Putting the fluid in the container does waste fluid and is a bit messy. Any disadvantages to not adding the fluid to the conatiner? Any problems with introducing air into the lines?

Thanks

Pugnacious

Pardon my ignorance on the subject but I don’t understand what is being accomplished by removing the old brake fluid and replacing it with air.

I do know that any air left in the system will give you a spongy brake feel which will only be exasperated when you get the brake fluid hot.

Brake fluid is messy and is no friend of paint but when I bleed my brakes I take every effort to NEVER introduce ANY air into the system.

StickShift964

Uhm...you will be bleeding your brakes forever if you keep adding air into the system. Think about it.

cviles

Just make sure to check the fluid level in the reservoir after bleeding each caliper. So long as you don't let the level get too low, you'll be fine and won't introduce any air into the system.

seattle_sun

Not what I ment. My question was if you use the Motive (without brake fluid in the canister) to push the brake fluid through, what are the chances of introducing air. Obviously, you don't want to add air to the system.

jnx

I never fill the Motive with fluid. As said before, you must top off the master cylinder after each wheel is bled. Do not let it get too low or you would introduce air into the system. I have never had any problems doing it this way and is much easier.

nkhalidi

The chances are EXTREMELY high. I'm no physicist, but even I can explain that pushing your brake fluid through the system using pressurized air - and not new fluid - increases your chances of introducing air to the brake system. Simply put, if you forget to check to ensure the master cylinder is full of fluid, you're going to begin pushing air through the car's brake system.

It's a waste of the motive to use it without fluid; the point of the system is that you can fill the bottle, pump it up, bleed to your heart's content, and be done with it.

The guy who replied before me, does he keep unscrewing and rescrewing the motive to make sure the master cylinder is full of fluid? Doesn't this seem superfluous?

Basal Skull

Not putting fluid in the motive itself is a pretty standard method. You don't have to unscrew, just look from the side - you don't unscrew the reservoir to check your brake fluid level each time do you? Most brake fluid (esp that blue stuff) you can see easily through the opaque container. You would have to unsrew to add fluid though, usually after each caliper. The chances of getting air in the system is pretty low (the reservoir is pretty big) haven't done it yet...the chance is the same if you're using a vaccum bleeder...or pumping the brake/old fashioned method... unless you can't do that on a 997?

Pugnacious

I have never used a non-diaphragm style brake bleeder and didn’t understand what you were talking about. I have always used a diaphragm style and couldn’t figure out how you could apply pressure to the system without adding brake fluid to the bleeder first. Sorry for being such a stooge.

TD in DC

I never put fluid in the motive bleeder itself. All you have to do is make sure that you check the fluid level before you move to the next caliper. There is zero chance that you will introduce more air into the system by using the motive empty as opposed to filling the motive. In BOTH cases you are using air to push the fluid. The fluid doesn't care whether it comes into contact with the fluid in the car or in the motive bleeder itself. The only way you will introduce air into the system is if you let the level get too low in the car. And, our systems are not really sealed in any event. Brake fluid is not as sensitive as some people tend to think. I have a buddy who has a brake fluid tester, and he has tested fluid in an open brake container about every six months, and you would be amazed at how little the fact that the container was opened affects the fluid.

TD in DC

It is not a waste of a motive to use it without fluid. When you are at the track, the last thing you want to do is to stop and really clean out the inside of the motive bleeder. If you do not clean it, the fluid will turn to jelly inside the pump and potentially contaminate fresh fluid the next time you use it.

Yes, you need to make sure that the brake fluid reservoir does not empty. But that is EASY . . . and far easier than cleaning out the motive when you are finished.

If you leave the motive dry, you just put in back in the box when you are done and you don't have to waste a second cleaning. Sure, you might waste a little time removing the bleeder, adding a little more fluid to the reservoir, and then repressurizing, but I am CERTAIN that this takes less time than it would take to clean the bleeder (and cleaing the jug is not sufficient -- you must clean the pump itself as well).

jnx

I am the guy who replied before you, and I can assure you it's not a waste of the Motive. Yes, I open the cap to re-fill after each wheel is bled. It's only 4 times and my arm does not get tired or sore or anything like that.

Like I said before, I have done this many times and know of many, many people who use it this way with no problems at all. If you don't wish to use it in this manner that's fine, just don't tell me it's a waste and not the proper way to do it.

Have you ever used one? Sounds to me like you don't know what you are talking about.

nkhalidi

I never said I knew a thing about fluid dynamics; in fact, I don't. I'm simply relaying my limited experience. That said, I do own a Motive and I've used it a few times

I stand by what I wrote: the Motive instructions specify using it with fluid, and that's what I've done, what I do, and what I'll continue to do. This method works for me with success, reliable results, and little chance of error. I was trying to relay my experience to the original poster and give some insight on my views.

It seems easier to me to fill the reservoir once, maintain pressure in it, and bleed normally opposed to your method. Do what you like; I didn't mean to demean you or your what works for you.

jnx

In either case, you use air to push the fluid out of the Motive. Without filling the Motive provides a much cleaner way to get the same result.

Pugnacious

After listening to you guys I’m sticking with my old (20+ year) Blue-Point diaphragm type bleeder where the air never touches the fluid.

Frankly, the non-diaphragm system sounds kind of Mickey Mouse to me knowing that air (water) and brake fluid don’t jive. I prefer to keep air, especially air under pressure, away from my brake fluid.