JCat

iTrader: (4)

I installed stainless brake lines all around this weekend and bled the brakes with this tool:



I removed the bleeder screws and put some grease on the threads to get a good air tight seal, before using this tool to suck the dirty fluid out at each wheel. I was as careful as I could be to get clean fluid entirely in each line, with no air. I was diligent in making sure the reservoir was nearly full at all times.

With the new stainless lines, I did notice a significant firmer brake feel, however I was curious about if I could get a better result by pressure bleeding the lines. . . . . . . so:

I re-bled the brakes by having my son press on the brake peddle while I opened the bleeder screws briefly (one at a time) and squirt a small amount of fluid out of them. I was careful to close the bleeder screw as the peddle was going down, and the fluid was flowing.

Afterwords, my brakes were slightly tighter. When I press the brake peddle now, there is absolutely no soft or compression feel in it.

Have you discovered that the pressure/pumping the brake peddle is the best way to bleed them ?

chrisjersey06

iTrader: (35)

That's what I did when my stainless lines went on, and there's no air in thereas far as I know. The pedal feels great. I think the best way is to have them vaccum bled, but I didn't see the need to after I did mine.

davidmcc

iTrader: (5)

I have both the Motive pressure bleeder and a similar vacuum tool to the one you have pictured. I prefer the pressure bleeder over the vacuum tool any day.

I bought the motive tool before doing my brakes after reading how difficult it was to get all of the trapped air out on a Z. When I finally did my brembo swap I bled my brakes far beyond what was needed because the motive tool did such a good job and made it so easy I was convinced that couldn't be all there was to it.

warmmilk

iTrader: (5)

does the motive pressure bleeder separate the pressurised air and the brake fluid or is it all in one chamber?




to OP:

http://www.zeckhausen.com/bleeding_brakes.htm

SOLO-350Z

iTrader: (26)

Motive Bleeder is the best I have used as well.

DavesZ#3

iTrader: (26)

+1 on the Motive bleeder. Positive pressure with fluid is the best method. Vacuum has the inherent risk of pulling in some air.

warmmilk

iTrader: (5)

anybody?

myork

iTrader: (5)

Its all in one chamber. Its kinda like those weed killer bottles, you fill it with fliud, then pump it up with air to create pressure. The difference is that you replace your reservoir cover with the one from the motive kit, which is attached to the bottle with a plastic air hose. When you open a bleeder screw at the caliper, the pressure in the bottle forces the fluid out of the bottle, into the master cylinder reservoir, through the brake line, and into the caliper.

One man job, no need for someone to pump the brakes while you open/close the bleeder screw.

I haven't tried them, but I have heard that speed bleeders work very well too. They are basically bleeder screws with a spring loaded ball bearing. You loosen the screw, and pump the brake. You dont have to worry about quickly tightening the screw because the spring and ball bearing prevent air from being introduced back into the system from the caliper.

warmmilk

iTrader: (5)

^I was afraid of that

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.


copy and paste from:
http://www.stoptech.com/tech_info/wp...fluid_1a.shtml

they also have an article on how to properly bleed brakes (i didn't read this one):
http://www.stoptech.com/tech_info/wp...edbrakes.shtml

DavesZ#3

iTrader: (26)

Wow, talk about nit-picking. That's a great article from Stoptech but they failed to recognize that nobody is going to own a professional bleeder. The Motive is the best that enthusiasts can hope to accomplish without buying a unit that cost more than a BBK.

Look at it this way - you fill the Motive tank with brake fluid and start pressurizing it. That may force some air into the solution at the surface, but it's not going to affect the stuff at the bottom of the tank. That's where the pickup is located. Unless you stir/shake the tank, all the "bad" fluid will stay at the top, far away from being used to replenish the brake system.

warmmilk

iTrader: (5)

well my point was more hinting at using the old fashioned 2 person method outlined in the link i posted in post 4 (i didn't read the link on how to bleed brakes that i posted from stoptech, so i can't comment on that).

Z1 Performance

iTrader: (564)

The 2 person method works perfectly well - it's worked for as long as we've had fluid assisted brakes. However, having 2 people isn't always possible, nor convenient...and that is where the Motive unit shines. Especially since it's inexpensive, and takes up next to no room on a shelf