Jump to content


Recommended Posts

Posted

Has anybody used this pressure bleeder? If so, what do you think of it as a brake bleeding tool? I've read about 95% success rate of this one man bleeder from users, how easy it is to use and how effective it is in bleeding/flushing the brake fluid, not mentioning its affordable price. At the same token it also has critics who insist that it allows air to get into the brake lines because the unit does not have a diaphragm that separates the air from fluid inside the bleeder's holding tank. Unlike the professional pressure bleeders which the cost is out of reach of ordinary people like us, Motive allows the compressed air that pushes the fluid into the car's fluid reservoir and out to the bleeder valves on the caliper, to mingle with the fluid, thus allowing air into the system. This is my main concern. But as I have read, the vast majority of people who have used this product are very satisfied with its performance with no complaints and have a very high success rate. It makes me wonder if the 10 to 15 PSI of air that you use to pressurize the brake line is minimal to negatively affect the brake fluid. Any comment on this?


Posted

I'm guessing there was supposed to be a link in this post?

I've used many self-bleeders, and as long as they all pull a vacuum, have a 'catch jar', and have a decent length of tubing running to the bleeder valve (to keep fluid in the line and not allow it to go back into the caliper), they all work well. Some are easier than others, but if 95% of the people find it easy to use, then it's probably not too bad.

Posted
I'm guessing there was supposed to be a link in this post?

I've used many self-bleeders, and as long as they all pull a vacuum, have a 'catch jar', and have a decent length of tubing running to the bleeder valve (to keep fluid in the line and not allow it to go back into the caliper), they all work well. Some are easier than others, but if 95% of the people find it easy to use, then it's probably not too bad.

Hi blk on blk,

What I'm talking about here is a pressure bleeder made by Motive. It pushes the pressurized break fluid from the master cylinder reservoir out to the bleeder valve. It is different from a vacuum bleeder which sucks the fluid from the bleeder valve. Although a vast majority of users approve of it, I could not help not ignoring entirely the following article from StopTech because it is very plausible:

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.

The professional units can cost hundreds of dollars, and for good reason; unfortunately the cost keeps them beyond the reach of most of us normal folks. Your best bet is probably to get back in the driver’s seat and begin stroking the pedal with your foot again, but ultimately the choice is yours.

Posted
I'm guessing there was supposed to be a link in this post?

I've used many self-bleeders, and as long as they all pull a vacuum, have a 'catch jar', and have a decent length of tubing running to the bleeder valve (to keep fluid in the line and not allow it to go back into the caliper), they all work well. Some are easier than others, but if 95% of the people find it easy to use, then it's probably not too bad.

Hi blk on blk,

What I'm talking about here is a pressure bleeder made by Motive. It pushes the pressurized break fluid from the master cylinder reservoir out to the bleeder valve. It is different from a vacuum bleeder which sucks the fluid from the bleeder valve. Although a vast majority of users approve of it, I could not help not ignoring entirely the following article from StopTech because it is very plausible:

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.

The professional units can cost hundreds of dollars, and for good reason; unfortunately the cost keeps them beyond the reach of most of us normal folks. Your best bet is probably to get back in the driver’s seat and begin stroking the pedal with your foot again, but ultimately the choice is yours.

Micklex- I am not going to put down the person who wrote that article for ShopTech. That would be absurd on my part. What he says is true, the problem is that's a perfect world and we don't live in a perfect world most of the time, if ever. The sky will not fall if you introduce low air pressure into the container with the fluid. Most tech's don't live in a perfect world, in spite of what you think. I spent most of my life in automotive work and most of that in dealers, a variety of brands. I have seen things done by PROFESSIONAL mechanics that would make your hair stand on end. No offense to those that are true professionals. How about a Mercedes tech that NEVER vacuumed a system that had been open, simply dumped the freon in. I won't go into the things I could write a book about, and I worked in good dealers, not flakes, but I literally laugh when I read "professionally maintained". You have no idea some of the things that are done even in high line dealerships. I have little doubt that there are people like Lenore and others on this forum that do a better job than SOME of what you paid $100. or more an hr. for. In my teens I worked in a dealership doing a variety of things, including light mechanical. It was what I saw even that early, that convinced me I wasn't much interested in having someone else work on my car.

Posted

Roger, you are absolutely right, the mechanics run the spectrum when it comes to their skills, and desire to do it right. I have been wrenching on cars since I was 15 and saw the good and bad when I worked in a gas station at age 15. Fortunately, my daddy being a air craft mechanic said never do a job unless you do it right, that is how I live, in everything I do. Yea, I make mistakes, but I fix them and learn. Still wrenching after 40 years, (mostly to save money, and have it done right) but that is why these forums are great, to help even those who do not diy to save money and learn how to not get cheated at the stealerships. Back to bleeding brakes, well I do it the old fashioned way, little woman pushes the pedal for me god bless her...

Posted

Ah, my bad... I should have paid a little more attention before I responded. Either way, I'm still a believer of working the master cylinder to pump brake fluid through, then either manually bleeding through pumping the pedal (if I could get my wife to help me with the job), or just finish it off with a one-man vacuum bleeder. I'm not much for pressurizing brake fluid to drive it through, nor risk getting air in the lines. I'll let the master cylinder and gravity drive it through.

Code58 & Lenore, I couldn't have said it better, my friends. You never really know what your getting with 'professional maintenance', for I've seen some pretty shady stuff in the short times I've been at various shops... and if you want it done right, you often have to get under the hood yourself (sometimes even when you've got a good shop you trust... which is hard to find; I trust the shop I go to, but there are still times when I need to stop and ask them, "now how did you go about doing that repair?"). Great posts guys!

Posted
Ah, my bad... I should have paid a little more attention before I responded. Either way, I'm still a believer of working the master cylinder to pump brake fluid through, then either manually bleeding through pumping the pedal (if I could get my wife to help me with the job), or just finish it off with a one-man vacuum bleeder. I'm not much for pressurizing brake fluid to drive it through, nor risk getting air in the lines. I'll let the master cylinder and gravity drive it through.

Code58 & Lenore, I couldn't have said it better, my friends. You never really know what your getting with 'professional maintenance', for I've seen some pretty shady stuff in the short times I've been at various shops... and if you want it done right, you often have to get under the hood yourself (sometimes even when you've got a good shop you trust... which is hard to find; I trust the shop I go to, but there are still times when I need to stop and ask them, "now how did you go about doing that repair?"). Great posts guys!

blk_on_blk- Since I was a kid, a long time ago, they have used pressure bleeders as the standard in all automotive shops that I ever worked in. There are obvious reasons for that. I still believe pressure bleeding is the gold standard, but out of the reach of the DIY mechanic. I have felt for some time that a device that used a flat plate with a rubber seal (probably neoprene, whatever is impervious to brake fluid) and rubber straps similar to what is used on most commercial bleeders for universal fit, a see through container of about 1 qt. with hose to plate, and something like is used in a cartridge grease gun for pressure would be easy to make and effective. The type of thing that uses a one way valve for the air, you retract the piston and lock it and once ready to bleed, release the piston and let the spring loaded piston do it's job. Simple and effective, because the piston should provide enough pressure to do a one man bleed and by spring pressure instead of compressed air, especially for those that don't have a compressor. The container and the pressure device could hang from the underside of the hood on an available lip and the see through container would let you check reserve fluid level at a glance. Who wants to be the 1st to try my poor mans bleeder? :D

To this point I have gotten along fine with the vacuum bleeder because I have some ADD (maybe a touch of ADHD) and in the shop and on commission When I needed a helping hand with something, time was money and you couldn't wait 10 or 15 min. for someone to get free to help you. I learned ways to do 2 man jobs alone. I have never been willing to compromise quality, so I figured ways to do the job right with 2 hands instead of 4. The 1 man bleeding is a result of that.

Posted

Hmm... that sounds like a pretty straightforward design, Code58. I'm a mechanical design engineer and that sounds like a pretty clean design for a poor man's bleeder. The only notable difference between the mechanical spring pressure system and an air pressurized system is probably the rate and consistency of flow (my understanding is one doesn't want to go over 20psi when pressure bleeding, and anything too low doesn't clean the residual bubbles remaining in the lines). Using air pressure as the driving force gives a nice, constant bleed rate (since the air source is usually a compressor with a large accumulator/tank... I don't know how well one can pressurize a hand-pumped pressure bleeder). If you used a spring system, you'd probably want a long travel spring, otherwise your flow rate would decrease as the spring unloaded... the whole Hook's Law theory. But then again the change in pressure/rate may not be that big of a concern/issue depending on the job at hand. I'm sure it could be done. You ought to prototype one, patent your refined design, sell the concept, and retire early :)

Posted
Hmm... that sounds like a pretty straightforward design, Code58. I'm a mechanical design engineer and that sounds like a pretty clean design for a poor man's bleeder. The only notable difference between the mechanical spring pressure system and an air pressurized system is probably the rate and consistency of flow (my understanding is one doesn't want to go over 20psi when pressure bleeding, and anything too low doesn't clean the residual bubbles remaining in the lines). Using air pressure as the driving force gives a nice, constant bleed rate (since the air source is usually a compressor with a large accumulator/tank... I don't know how well one can pressurize a hand-pumped pressure bleeder). If you used a spring system, you'd probably want a long travel spring, otherwise your flow rate would decrease as the spring unloaded... the whole Hook's Law theory. But then again the change in pressure/rate may not be that big of a concern/issue depending on the job at hand. I'm sure it could be done. You ought to prototype one, patent your refined design, sell the concept, and retire early :)

Too late. :lol: And it wasn't early either! :lol:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×
×
  • Create New...

Forums


News


Membership


  • Unread Content
  • Members Gallery