I would agree that a power bleeder is a great investment. I am fotunate to have access to a justice brothers brake flush machine at work and it does wonders. I no longer have to bench bleed master cylinders and bleeding stubborn ABS units is a thing of the past. if you combine the pressure and vacuum tools together it makes the job much cleaner and less time consuming.
Changed My Brake Fluid and...WOW.
- Thread starter The Critic
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How much fluid should I buy to bleed the brakes on a small car?
Originally Posted By: Shaman
How much fluid should I buy to bleed the brakes on a small car?
1 quart.
How much fluid should I buy to bleed the brakes on a small car?
1 quart.
Sounds good.
Originally Posted By: moribundman
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
The problem is vacume bleeders The seals work with pressure
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
Originally Posted By: Shaman
How much fluid should I buy to bleed the brakes on a small car?
I just did my front and rear brakes on my Corolla - with the removal of the old fluid from the master cylinder, I used about 500 mL of Castrol LMA fluid.
How much fluid should I buy to bleed the brakes on a small car?
I just did my front and rear brakes on my Corolla - with the removal of the old fluid from the master cylinder, I used about 500 mL of Castrol LMA fluid.
Originally Posted By: Steve S
Originally Posted By: moribundman
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
The problem is vacume bleeders The seals work with pressure
This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
Pressure bleeding on its own is not necessarily a bad thing, but there are several steps one must take to ensure that the bleed event will result in an air-free brake system.
When we talk about pressure bleeding, we are referring to the process in which we pour our brake fluid into a pressure vessel, hook up a pressure source, and run the now pressurized fluid directly into the master cylinder reservoir. One by one the caliper bleeder screws are opened to allow the pressurized fluid to flow through the system until all of the old fluid has been purged. Simple, right?
Well yes, but beware of imitations – not all pressure bleeders are created equal. The professional units (the type you can consider using) separate the pressurized brake fluid from the pressure source (air) using a flexible rubber diaphragm. In this fashion, the pressurized air is kept from forcing its way into the fluid. As we all know, air and fluid should be kept as far apart as possible.
This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. Like most things that sound too good to be true, well, it’s exactly that.
Like the professional units, these imitations contain a pressure vessel into which new brake fluid is poured. However, in order to pressurize the fluid, an integral pump handle is cycled to build the pressure inside the vessel without any measures taken to separate the pressurized air from the fluid. For those of you who have ever bought a $19.95 do-it-yourself potted plant and bug sprayer from Home Depot you get the idea.
Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!
While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. This of course begs the question: if you are stuffing air and water contaminated fluid into your brake system, why even bother bleeding it in the first place?
Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM. Talk about an expensive process! If just storing your fluid under regular atmospheric conditions isn’t good enough to keep air and water out, just imagine what shoving 30psi worth of compressed air on top of it is doing.
"
Originally Posted By: moribundman
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
Pressure bleeding on its own is not necessarily a bad thing, but there are several steps one must take to ensure that the bleed event will result in an air-free brake system.
When we talk about pressure bleeding, we are referring to the process in which we pour our brake fluid into a pressure vessel, hook up a pressure source, and run the now pressurized fluid directly into the master cylinder reservoir. One by one the caliper bleeder screws are opened to allow the pressurized fluid to flow through the system until all of the old fluid has been purged. Simple, right?
Well yes, but beware of imitations – not all pressure bleeders are created equal. The professional units (the type you can consider using) separate the pressurized brake fluid from the pressure source (air) using a flexible rubber diaphragm. In this fashion, the pressurized air is kept from forcing its way into the fluid. As we all know, air and fluid should be kept as far apart as possible.
This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. Like most things that sound too good to be true, well, it’s exactly that.
Like the professional units, these imitations contain a pressure vessel into which new brake fluid is poured. However, in order to pressurize the fluid, an integral pump handle is cycled to build the pressure inside the vessel without any measures taken to separate the pressurized air from the fluid. For those of you who have ever bought a $19.95 do-it-yourself potted plant and bug sprayer from Home Depot you get the idea.
Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!
While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. This of course begs the question: if you are stuffing air and water contaminated fluid into your brake system, why even bother bleeding it in the first place?
Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM. Talk about an expensive process! If just storing your fluid under regular atmospheric conditions isn’t good enough to keep air and water out, just imagine what shoving 30psi worth of compressed air on top of it is doing.
"
Last edited:
The last time I checked...which was about a month ago...my new bottles of Valvoline brake fluid were not in vacuum packaged containers. I know from reading on this forum that brake fluid is highly hygroscopic. So, how aeration prone is it?
I do not know how easily it is to aerate brake fluid as is what is stated in Thingfish's quote. If it is easy to aerate, then the bladder may be needed. If it is difficult to aerate (say three or four atmospheric pressures to aerate the fluid), then the above is just sales hype and failed attempt to disqualify a less expensive alternative to their "high-zoot professional unit."
1 psi = 0.0680459639 atm So, 15 psi = 1.0207 atm,
20 psi = 1.361 atm.
My directions for my Motive brake bleeder say 15 psi maximum, and it works just as well at 10 psi, just slower.
So, the question. At what PSI does brake fluid aerate, and thus, trapping air in the line with its inherent H20?
Off topic... I will not be stocking up on brake fluid. Nor will I be storing it in my garage if I do have some. It will have to be stored in the environmentally controlled home. Maybe I'll check the humidity level on the day I bleed my brakes, maybe. It was not a problem in the desert of Arizona on a 10% humidity day. Possible problem here in the South on an 70% humidity day. Hmmm... never thought of that before.
I do not know how easily it is to aerate brake fluid as is what is stated in Thingfish's quote. If it is easy to aerate, then the bladder may be needed. If it is difficult to aerate (say three or four atmospheric pressures to aerate the fluid), then the above is just sales hype and failed attempt to disqualify a less expensive alternative to their "high-zoot professional unit."
1 psi = 0.0680459639 atm So, 15 psi = 1.0207 atm,
20 psi = 1.361 atm.
My directions for my Motive brake bleeder say 15 psi maximum, and it works just as well at 10 psi, just slower.
So, the question. At what PSI does brake fluid aerate, and thus, trapping air in the line with its inherent H20?
Off topic... I will not be stocking up on brake fluid. Nor will I be storing it in my garage if I do have some. It will have to be stored in the environmentally controlled home. Maybe I'll check the humidity level on the day I bleed my brakes, maybe. It was not a problem in the desert of Arizona on a 10% humidity day. Possible problem here in the South on an 70% humidity day. Hmmm... never thought of that before.
Originally Posted By: Thingfish
http://journals.pepublishing.com/content/jp71574546245610/
That abstract (as I could not read the entire article without payment) says nothing of how the air got in the system. Nor does it test at what PSI or ATM the air gets into the brake fluid. It just concludes that air in the brake system/fluid is less efficient than brake fluid without air in it. Really? The OP "The Critic" had an improvement when he was able to get the air out of his calipers using this system. It is possible, maybe even highly possible that the high-zoot professional unit would improve his braking performance further. That we will probably never know. However, I'll bet there is a professional on this board that does know.
I have also had dramatic improvement in brake response after using the Motive system. It is difficult to argue with success, but you may continue.
The question for the professionals/experts remains....At what PSI does brake fluid aerate? Maybe a new thread needs to be had for this question.
Bottom line. The Motive system worked for the OP, I have had good success with the system. A study is needed with brake response after bleeding the system with the Motive unit vs. the high-zoot professional unit. Until this is done, it is all conjecture, with the BIG ASSUMPTION that the motive is aerating the brake fluid when used and the high-zoot professional unit is not.
http://journals.pepublishing.com/content/jp71574546245610/
That abstract (as I could not read the entire article without payment) says nothing of how the air got in the system. Nor does it test at what PSI or ATM the air gets into the brake fluid. It just concludes that air in the brake system/fluid is less efficient than brake fluid without air in it. Really? The OP "The Critic" had an improvement when he was able to get the air out of his calipers using this system. It is possible, maybe even highly possible that the high-zoot professional unit would improve his braking performance further. That we will probably never know. However, I'll bet there is a professional on this board that does know.
I have also had dramatic improvement in brake response after using the Motive system. It is difficult to argue with success, but you may continue.
The question for the professionals/experts remains....At what PSI does brake fluid aerate? Maybe a new thread needs to be had for this question.
Bottom line. The Motive system worked for the OP, I have had good success with the system. A study is needed with brake response after bleeding the system with the Motive unit vs. the high-zoot professional unit. Until this is done, it is all conjecture, with the BIG ASSUMPTION that the motive is aerating the brake fluid when used and the high-zoot professional unit is not.
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Originally Posted By: Steve S
Originally Posted By: moribundman
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
The problem is vacume bleeders The seals work with pressure
I never posted what's attributed to me after the smilie. It's not even a proper sentence.
Originally Posted By: moribundman
Originally Posted By: Thingfish
Critic, I cannot tell, does that system separate the pressurized air from the reserve brake fluid?
Uhm, how exactly do you think air will get into the fluid when you pressurize the pressure bleeder?
I never posted what's attributed to me after the smilie. It's not even a proper sentence.
Originally Posted By: Thingfish
...................This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
......................This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. ....................While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. ...................Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM.............
Stoptech is making some reasonable conjectures here about air being forced into the brake fluid. But now they need to provide some test DATA showing that under the pressures and time limitations that one would experience when using the MP bleeder, a damaging amount of air is actually introduced. Without data, this just remains conjecture.
...................This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
......................This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. ....................While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. ...................Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM.............
Stoptech is making some reasonable conjectures here about air being forced into the brake fluid. But now they need to provide some test DATA showing that under the pressures and time limitations that one would experience when using the MP bleeder, a damaging amount of air is actually introduced. Without data, this just remains conjecture.
- Joined
- Jun 2, 2003
- Messages
- 23,591
Originally Posted By: Thingfish
This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
Pressure bleeding on its own is not necessarily a bad thing, but there are several steps one must take to ensure that the bleed event will result in an air-free brake system.
When we talk about pressure bleeding, we are referring to the process in which we pour our brake fluid into a pressure vessel, hook up a pressure source, and run the now pressurized fluid directly into the master cylinder reservoir. One by one the caliper bleeder screws are opened to allow the pressurized fluid to flow through the system until all of the old fluid has been purged. Simple, right?
Well yes, but beware of imitations – not all pressure bleeders are created equal. The professional units (the type you can consider using) separate the pressurized brake fluid from the pressure source (air) using a flexible rubber diaphragm. In this fashion, the pressurized air is kept from forcing its way into the fluid. As we all know, air and fluid should be kept as far apart as possible.
This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. Like most things that sound too good to be true, well, it’s exactly that.
Like the professional units, these imitations contain a pressure vessel into which new brake fluid is poured. However, in order to pressurize the fluid, an integral pump handle is cycled to build the pressure inside the vessel without any measures taken to separate the pressurized air from the fluid. For those of you who have ever bought a $19.95 do-it-yourself potted plant and bug sprayer from Home Depot you get the idea.
Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!
While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. This of course begs the question: if you are stuffing air and water contaminated fluid into your brake system, why even bother bleeding it in the first place?
Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM. Talk about an expensive process! If just storing your fluid under regular atmospheric conditions isn’t good enough to keep air and water out, just imagine what shoving 30psi worth of compressed air on top of it is doing.
"
Professional pressure bleeders may well contain a membrane that prevents contact between brake fluid and air, because these pressure bleeders are very likely doing double duty as used as storage containers. The membrane will prevent absorption of moisture out of the air into the brake fluid over time.
I do not believe, unless anybody explains and backs up with evidence, the existence of a physical principle that allows air pressure to "force air" into a fluid without electrical or mechanical aeration (stirring, shaking, diffusing etc, all of which increase the surface area and gas transfer rate).
Ambient air pressure at sea level is about 14.7 psi. If one applies with a pressure bleeder 30 psi air pressure to ambient air pressure, a total of 44.7 psi exerts force on the brake fluid inside the pressure belleder. That's roughly triple the ambient air pressure. Water absorption out of the air may well occur at a higher rate under elevated ambient atmospheric pressure than it does at lower pressure due to "augmented diffusion," but we are talking about a short period of time here.
This is from STOPTECH...
"Originally Posted By: Stoptech
Pressure bleeding do's and don'ts
Pressure bleeding on its own is not necessarily a bad thing, but there are several steps one must take to ensure that the bleed event will result in an air-free brake system.
When we talk about pressure bleeding, we are referring to the process in which we pour our brake fluid into a pressure vessel, hook up a pressure source, and run the now pressurized fluid directly into the master cylinder reservoir. One by one the caliper bleeder screws are opened to allow the pressurized fluid to flow through the system until all of the old fluid has been purged. Simple, right?
Well yes, but beware of imitations – not all pressure bleeders are created equal. The professional units (the type you can consider using) separate the pressurized brake fluid from the pressure source (air) using a flexible rubber diaphragm. In this fashion, the pressurized air is kept from forcing its way into the fluid. As we all know, air and fluid should be kept as far apart as possible.
This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. Like most things that sound too good to be true, well, it’s exactly that.
Like the professional units, these imitations contain a pressure vessel into which new brake fluid is poured. However, in order to pressurize the fluid, an integral pump handle is cycled to build the pressure inside the vessel without any measures taken to separate the pressurized air from the fluid. For those of you who have ever bought a $19.95 do-it-yourself potted plant and bug sprayer from Home Depot you get the idea.
Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!
While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. This of course begs the question: if you are stuffing air and water contaminated fluid into your brake system, why even bother bleeding it in the first place?
Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM. Talk about an expensive process! If just storing your fluid under regular atmospheric conditions isn’t good enough to keep air and water out, just imagine what shoving 30psi worth of compressed air on top of it is doing.
"
Professional pressure bleeders may well contain a membrane that prevents contact between brake fluid and air, because these pressure bleeders are very likely doing double duty as used as storage containers. The membrane will prevent absorption of moisture out of the air into the brake fluid over time.
I do not believe, unless anybody explains and backs up with evidence, the existence of a physical principle that allows air pressure to "force air" into a fluid without electrical or mechanical aeration (stirring, shaking, diffusing etc, all of which increase the surface area and gas transfer rate).
Ambient air pressure at sea level is about 14.7 psi. If one applies with a pressure bleeder 30 psi air pressure to ambient air pressure, a total of 44.7 psi exerts force on the brake fluid inside the pressure belleder. That's roughly triple the ambient air pressure. Water absorption out of the air may well occur at a higher rate under elevated ambient atmospheric pressure than it does at lower pressure due to "augmented diffusion," but we are talking about a short period of time here.
Originally Posted By: moribundman
but we are talking about a short period of time here.
that's the kicker. what takes months at atmospheric to get absorbed by the brake fluid may become a month or weeks under 3x atmospheric.
You're only still doing the brakes for an hour or two... no discernible difference.
but we are talking about a short period of time here.
that's the kicker. what takes months at atmospheric to get absorbed by the brake fluid may become a month or weeks under 3x atmospheric.
You're only still doing the brakes for an hour or two... no discernible difference.
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