The Homestretch!

After the brake lines are installed it is time to bleed them. There are lots of differing methods and tools that can be used to do this job and picture three shows the tool I used. You may remember it from tank testing. It is an air pump that can be set to pressurize, as I did with the tank, or set to create a vacuum, which is what I did here.

My method is to hookup the vacuum pump to the brake fluid reservoir and start sucking the fluid up from the caliper to the reservoir. Since the pump doesn’t create a lot of head pressure, I elevate the fluid can at least as high as the reservoir. Before I start pumping, I open the valve on the caliper and attach the hose from the can to the caliper valve fitting. When I start pumping the fluid starts to flow and travels several inches with each pump.

I keep it up until the reservoir is just starting to fill from the bottom. Then I follow the same procedure on the other gear leg. Since the fuselage brake lines are translucent, I can see the fluid moving through the brake lines all the way up to the reservoir.  When the second set of lines reache the reservoir, I continue pumping until the reservoir is about 2/3 full.

I don’t seem to have any bubbles between the brake cylinders and calipers and the brake pedals are solid when I try to push on them. The real test will come when I try to taxi, but so far I think they are fine. After several months of sitting in the garage, I have not seen any evidence of leaks anywhere in the system. Again, use will prove out whether they are fine.