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I was watching a youtube video of an Australian Waiex builder the other day, and noticed his bleeders seemed to be on the bottom. Zoop forward to about 15:30 in this video:


I also noticed in one of Bill's posts that his looked the same:


Conventional wisdom would say the bleeders should go on the high spot of the caliper, so the air bubbles can be forced out. And, when I look at the .pdf I downloaded from Sonex on the aerobrakes, for the titanium rod gear airplanes it shows the bleeder up high. Although for the Onex it shows the bleeder low, and I'm not sure why.

From the comments in that video and discussion with Bill it sounds like they have hydraulic brake instructions in the B model plans. I don't think we had that in the A model plans. And, it seems to indicate to install the bleeders on the bottom. Does this make any sense?

Hi Bryan,

It makes sense if you bleed from the bottom up, i.e. pushing fluid through the bleed screw up to the master cylinder until it is full. This is how I do my system now; however, I originally bled my system using vacuum through the bleed screw but found the vacuum was prone to sucking air through the caliper seals and introducing air.

For what it's worth; I find it pays to be flexible in the way aircraft brakes are bled/filled. I usually start by pressure "bleed" from the bottom up, using a disposable syringe AND will bleed down if the need arises. When bleeding down, I use the traditional pumping of the brake master cylinders.

Page L-07 in the Legacy Waiex plans do indeed show the bleeders on top.

The B model plans do show them on the bottom. Somebody sent me a snip. Still not sure how the bubble gets out of the top corner even if you push fluid in from below. I wonder why the change?

Area 51% wrote:Page L-07 in the Legacy Waiex plans do indeed show the bleeders on top.

My circa 2013 legacy plans do not show any hydraulic brake details. My copy of the Aerobrakes manual show them on top for the ti gear. You can find the latest here:
http://www.aeroconversions.com/support/manuals.html

In other news I bled the brakes solo last night, after redoing one of the compression elbows. I did use the syringe from the bottom trick, and then one pump up top using a bungee cord. I have brakes again.

My plans for W0218 (2016) do not differentiate between standard gear and tricycle. It just shows the caliper on the axle. .
The plans for Chett W0212 (2015) were the same.