View Full Version : Gravity bleeding

04-04-2006, 02:33 PM
Can someone tell me step by step how to gravity bleed a brake system. Do you crack all 4 at once? start from the furthest and go closest? Closest to furthest? How long? Please help as I want to do my brakes tonight and tomorrow and this would be easy because I have time.

04-04-2006, 03:28 PM
Brake Bleeding Methods

There are three methods of bleeding that can be done without prohibitively expensive equipment: manual brake bleeding, vacuum brake bleeding, and gravity brake bleeding. Whether bleeding a master cylinder on a bench, or a brake caliper or wheel cylinder on the car or truck, the principle is the same. You want to force air and fluid out and add new fluid, all while preventing fresh air from entering the system. Regardless of the method you choose, you'll quickly realize the trick is to keep the brake fluid moving in only one direction; from the master cylinder through to the brake calipers or wheel cylinders. Be sure to keep topping up the master cylinder with brake fluid as you bleed each wheel and after you are finished to prevent it from running low and pulling fresh air into the system. When the system is full of clean brake fluid and there is no air trapped inside, the brake pedal should be high and firm.

Method 1: Manual Bleeding

Manual brake bleeding is the most common method of bleeding brakes; however, you will need to enlist the help of an assistant. With your assistant sitting in the driver's seat, repeat the following six steps a number of times on each brake until you are sure there is no air trapped in the system. Use a narrow block of wood behind the pedal to prevent it from travelling all the way to the floor. Lastly, place a three foot piece of vinyl hose on the end of the bleeder screw to direct old fluid into a plastic container.

Instruct your assistant to pump the brake pedal for thirty seconds
Instruct your assistant to press and hold the brake pedal firmly
Open a bleeder screw and let the air and old fluid escape
Close the bleeder screw
Instruct your assistant to release the brake pedal
Wait fifteen secondsMethod 2: Vacuum Bleeding

Vacuum bleeding has the advantage of being a one-person job, but requires a special tool known as a vacuum tester or brake bleeding kit. The tool is fairly inexpensive and can be ordered online by clicking on the link above. Whereas manual brake bleeding requires you to "push" brake fluid out; the object of vacuum bleeding is to "pull" brake fluid out. Repeat the following three steps on each brake.

Connect the hose from the vacuum tool to the bleeder screw and then open the bleeder screw
Pump the tool until the fluid leaving the bleeder screw runs clean and is free of bubbles
Close the bleeder screw and disconnect the vacuum tool hoseMethod 3: Gravity Bleeding

Gravity bleeding is the easiest method of bleeding brakes. Simply, repeat the following two steps on each brake. Unfortunately, leaving the screw open for any length of time will allow it to absorb moisture. Additionally, air bubbles may be trapped in the system and need to be worked out using a vacuum or pressure bleeding method. The gravity bleeding method can be used when only a brake caliper or wheel cylinder was replaced.

Open one bleeder screw at a time and wait until the air works its way out of the system
Close the bleeder screw when clean brake fluid runs from the bleeder screwhttp://www.carcentral.net/content/guides/HowToBleedABrakeSystem.php

04-04-2006, 08:54 PM
If you have an aftermarket rear disc set-up the caliper on the rear could be turned where the bleeder screw is not at the top and you cannot get all the air out of the caliper. You would have to drive it in a ditch to get the rear end up so that the bleed screw is at the top of the caliper, or you can get a thick piece of metal plate, take off the caliper and put the plate in the caliper between the pads and bleed the caliper that way.

The other way you can start bleeding the brakes is put a stick on the brake pedal wedged under the steering wheel holding the pedal down. Leave it like that over night and the air will travel up to the MC and vent out. I would not trust this alone, i would then follow sally's directions on the final bleeding process.

The last thought is the order of bleeding the Sami's brakes. If you are still in stock configuration of the brake lines there is an unusual order to bleed the brakes. It is not the traditional way you would do any other car and for the life of me I don't remember the specific order. Hopefully someone else will chime in.

04-04-2006, 09:22 PM
Thanks joe. I have a stock line config. but my axles are 10 bolt GM and I have the brakes set up in stock form. I will need to bleed the brakes the same as a zuk so I will need the pattern. Isnt it DF PF PR DR? Because the zuk has the lines come off the pass side in the rear so the DR is longer than the PR correct?

04-04-2006, 09:44 PM
I looked in the FSM and it says to do the LR, RR, RF then the LF. This is right. You want to start with the longest brake line first and since it goes to the porportioning valve on the passenger side the drivers side rear would be the longest.

Even with the different axles under your rig make sure the bleed screw is at the top of each caliper or it will trap air.

04-04-2006, 09:44 PM
One of the most awesome products out there are speed bleeders. One man bleeding system and they are cheap too. All you do is loosten like you would a regular bleeder and pump the pedal a couple times, close them and good to go lets fluid and air out and wont let air back in. HTH

04-04-2006, 10:44 PM
One of the most awesome products out there are speed bleeders. One man bleeding system and they are cheap too. All you do is loosten like you would a regular bleeder and pump the pedal a couple times, close them and good to go lets fluid and air out and wont let air back in. HTH


04-05-2006, 04:13 PM
How about that spellcheck..LOL

04-05-2006, 04:23 PM
How about that spellcheck..LOL

Check this out...



04-05-2006, 08:52 PM
I bleed mine by myself...here's how I do it. I hook a piece of tubing up to the bleeder, long enough to reach the floor. I then put a bottle of fluid, about half full on the floor and submerge the end of the tube into the fluid. I crack the bleeder, pump the brakes, and check the tube periodically to see if it's full of fluid. Once the tube if full of fluid with no air in it, pump 'em a few more times for good measure, close the bleeder and you're done. Because the tube is submerged it can't let air into the system...toast Clear tubing works best for visual check...