Piper Aircraft Brake Bleeding

Hey all, Below I share with the aviation maintenance community how I prefer to bleed Piper PA-28/32 brakes. How do you guys bleed Piper brakes? Did my method work well for you guys?

Important Note: This is advice only. Please refer to latest manufacture guidance.

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Piper Aircraft Brake Bleeding

Methods I've Tried

Article: Piper Aircraft Brake Bleeding

#1 Old Fashion Oil Chan & Flex Hose

This method did not work for me. This is where you take an old school oil can, attach a short length of flexible hose. Then attach the flexible hose to the brake housing (located at the aircraft wheel).

#2 Pressure Pot Home Made

This method includes a pump up weed sprayer, a few barb fittings, and clear tubing. These items can be found at most hardware stores. Make sure to get the tube ID so it fits snug on the brake bleeder valve. I’ve gotten this method to work, but I had to go back in the cockpit and open up fittings near the brake actuator lines to release air bubbles. 

#3 Pressure Pot ATS Tool

This method is similar to method # 2 above except the tools is designed for the purpose of aircraft brake bleeding. The best part about this unit is the fitting used to hook to the bled valve on the brake. The fitting allows you to tighten the connection, and allows little to no leakage when bleeding. Ultimately this method didn’t work as well for bleeding piper brakes. The ATS Brake Bleeder 225 is still a great tool, and we use it for other aircraft. 

#4 Pressurizing The Brake Reservoir

This method requires screw on cap that fits the Piper brake reservoir. I don’t have a picture of the set-up I used. Essentially I took a screw on cap, drilled a hole in the middle, and epoxied a barb fitting to the cap. Then I attached a pressure pot with hose to the barb fitting. This method one of the better methods, but my favorite method is much simpler. See “Method I Use Now”

Method I Use Now

Article: Piper Aircraft Brake Bleeding

Using Aircraft Brakes With Bleed Hoses

This simple system is one I found to be the fastest and easiest way to bleed Piper aircraft brakes. The materials you’ll need are listed below.

Step 1: Attach clear tubing from each bleed valve (located at brake) to the brake reservoir located on the RH forward side of the firewall. Use painters tape to take the hose to the aircraft to keep in place.

Step 2: Top Off the brake reservoir with 5606 Hydraulic fluid. In addition, keep a quart or gallon of 5606 hydraulic fluid handy for keeping the reservoir full. 

Step 3: Open the bleeder valve one side (Left or Right) using a 1/4 wrench. I’ve had the most success doing one side at a time.

Step 4: Using the hand brake and brake pedal pump the fluid through the system. Only pump the brake in which you are working on. You should monitor the clear tube for fluid flow and bubbles. Alternate pumping the hand brake and foot brake. The hand brake seams to flow the most fluid, and I use it the most. Check the brake reservoir periodically and pump until you get no bubbles. 

Step 5: Close the brake valve with the 1/4 inch wrench. The repeat steps 1 through 4 on the other brake.

Step 6: When completed check the braking action by pedal/hand brake firmness. You can also have a second person push on the leading edge of the wing while another person holds the brake. Does the plane roll? If you fail on the first bleed attempt try again. If you can’t get it to bleed then I recommend rebuilding the hand and pedal brakes. Often times the seals are worn which prevents proper bleeding. 

Materials Needed

Trick I Learned Recently

Article: Piper Aircraft Brake Bleeding

Pre-Fill Brakes When Changing O-Rings

So recently I worked with another shop, and the owner of this shop showed me a trick that works pretty well. This applies to 0-ring replacement in the brake housing. This short cut prevents you from bleeding brakes after the o-ring change.

Step 1: Remove the brake housing and cap the aircraft line side to prevent fluid from draining.

Step 2: Replace o-ring as usual in brake housing. 

Step 3: Fill the piston cavity with 5606 prior to putting piston back in housing. You can push some fluid out by pressing the piston into the housing slightly (make sure bleed valve is closed)

Step 4: Place the pre-filled brake housing back on the aircraft and connect the aircraft side brake line. 

The key to making this trick work is to keep air out of the brake housing. When installing the pre-filled housing you can even connect the aircraft side brake hose. Then before tightening completely press the piston slightly to bleed/flush air from the housing at the airframe hose to brake housing connection. 

Michael Sawyer

Michael Sawyer

Michael is an A&P / IA with 15 years experience in aviation maintenance. This experience includes general aviation, corporate, and military. Michael has owned and operated aviation businesses since 2015. Currently he's helping others with aviation maintenance entrepreneurship. Email: msawyer@phalanxaviation.com