The last time I spoke with Brett at Bonaco, he indicated that they now have black anodized fittings, so I ordered replacement AN822-3D fittings and new hoses from the reservoir to the master cylinder with black fittings on each end. This looks so much nicer now that everything associated with the brakes and rudder pedals is black anodized aluminum.
I torqued down all of the fittings and decided to fill the brake system tonight. I’m using Royco 782 fluid. I was able to find quart sizes of this at SkyGeek.com.
Royco 782 is a MIL-PRF-83282 fluid which is the replacement for MIL-H-5606 and has a much higher flash point. There have been brake fires with MIL-H-5606, so I didn’t want to use that.
The general consensus seems to be to use a pressure system to fill the brake system from the bottom, but people sometimes still have issues with bubbles in the system. Getting the bubbles out of the system has nothing to do with the direction you fill the system, it’s all about getting a high flow rate through the system. If the flow rate is too slow, bubbles will get stuck in high spots in the system since they tend to migrate fairly slowly through the narrow lines. With a high enough flow rate, the bubbles can’t help but be carried along with the fluid.
Instead, what I did was create a closed system to pump the brake fluid through. I hooked up a fitting and hose to the brake fluid reservoir and put the other end in the can of brake fluid. I then hooked up another hose to the fitting on the bottom of the wheel caliper and also put that hose in the can of brake fluid. Now, as fluid is pumped out of the can and through the system, it’s returned back to the can. All I had to do after that was operate the brake pedals fully and moderately quickly until nothing but clean fluid was being pumped back into the can. This only took about 30 seconds on each side. The brakes are absolutely rock solid and no leaks!
