I was asked to post my version of a pressure brake bleeder.  In the interest of disclosure, I did not invent this.  There are numerous commercial versions for sale and there are numerous U-Tube videos on how to make your own.  This post is what I did.

I bought a one gallon garden sprayer, twenty feet of 3/8 i.d. vinyl tubing, and a screw on valve stem. If you omit the valve at the master cylinder you will need a 1/4NPT x 3/8 barbed brass fitting.  Everything else you will see came from my stores in my shop.  If you buy everything new at Home Depot, your total cost should be about $30.

Carefully cut a hole for the valve stem in the top shoulder of the sprayer container. Deburr the hole and clean the plastic shavings from the container.  Screw the valve stem into the container as shown.  I will probably modify this to include a pressure gauge down the road. The valve stem allows you to vent off the container pressure.



Attach the vinyl tubing to the control valve (orange thingy) with a hose clamp. Attach the other end of the vinyl tubing to the master cylinder adapter.



The master cylinder adapter is made from 1/4" aluminum plate, drilled and tapped for 1/4"NPT for the brass fittings.  I added the valve to allow filling the tubing without having to worry about spilling brake fluid all over the place.



The bottom of the adapter plate is covered with rubber gasket material glued on with 3M spray adhesive.  This adapter is for the cast iron master cylinders with the flat top edges.  For the later model plastic master cylinder reservoirs with the screw caps, you will have to acquire another cap and drill and tap it for the 1/4" NPT fitting.

You can see the pattern of the top of the cast iron reservoir bowls on the rubber.


I make some simple clamps to hold the adapter plate to the master cylinder.  The pump on the sprayer will make about 20psig, but I doubt that much pressure is needed.  Using two of the clamps pictured, I was able to pump the sprayer close to maximum pressure, but I doubt I will do that again.  Just enough pressure to make the brake fluid flow is probably the right amount.



The clamps are nothing special, just a piece of 1/8' bar, some plumbers strap, 1/4-20 allthread, nuts and washers.

To use:
Pour a quart of your favorite brake fluid (Dot 3 for most of us) in the container, screw in the pump and pressurize the sprayer.  If you added the valve on the master cylinder end open that valve and hold it up in the air, open end facing up.  Use the sprayer control valve to charge the vinyl tubing with brake fluid and close the valve at the adapter plate.

Pull the cover off the master cylinder and locate the adapter plate over the bowl you plan to pressurize.  make sure the rubber gasket is seated all the way around that bowl.  Tighten the clamps to seal the adapter to the bowl. 

Using the twenty feet of vinyl tubing, carry the pressure bleeder container to the first brake to be bled.  Attach a catch can to the bleeder screw for that brake with tubing (a one liter soda bottle works well. Drill a hole in the cap for the tubing and another for a vent). Then open the bleeder screw about a quarter of a turn.  Use the pressure bleeder control valve to pressurize the master cylinder bowl.  There is very little volume in the brake tubing between the master cylinder and even the right rear wheel, so if you already have the system charged with brake fluid it should only take a few seconds to purge all the air from the system.  If you are charging the system for the first time, or are flushing the brakes, it may take twenty to thirty seconds.  Watch the catch can to make sure you don't overflow it, it's easy to do with the pressurized supply.  Close the brake bleeder screw and pull the catch can tube off the bleeder screw. Repeat on as many wheels as necessary.  For a four wheel brake system bleed, the standard routine is to start at the wheel furthest from the master cylinder and work your way to the closest, typically, right rear, left rear, right front, left front.

When you are through, bleed the pressure off the container with the valve stem.  I personnally plan to empty my pressure container of brake fluid, wash out with water, dry with compressed air, and store dry.  Brake fluid is about $6/qt. so it is not worth keeping an open partially empty container around.  Brake fluid is very hygroscopic, meaning it attracts water, pulling moisture out of the air.  Even "tightly sealed" partial containers of brake fluid can pull moisure through those seals.  It is good technique to use a new, never opened container of brake fluid every time you need some. Brake fluid is just like caulk, it never gets better sitting on the shelf, it can only get worse.

The pressure bleeder makes it possible for one person to do a good job of bleeding brakes.  Does not work with antilock systems.

BE VERY CAREFUL WITH THE PRESSURIZED BLEEDER SYSTEM!!!  SINCE THE BRAKE FLUID IS UNDER PRESSURE, IT IS POSSIBLE TO SPRAY BRAKE FLUID A GREAT DISTANCE AND IN LARGE QUANTITIES.  BRAKE FLUID IS REALLY GOOD AT TAKING PAINT OFF, SO BE CAREFUL.

If you get brake fluid on paint you want to keep, flush the brake fluid off with cold water.  A hose with nozzle works well.  If you are where there is no hose available, another garden sprayer filled with water will do.  Lable both containers so you do not get them confused.