G-UFOX - Brakes (Stuff We Have Learnt)
Our plane is a taildragger with toe brakes only on the left-hand pilots side. The nosewheel version is different.
The Parking Brake facility is accomplished by a pair of valves in the brake lines (one for each main wheel). To operate, you put your feet on the brakes to put pressure in the lines, then close these valves to retain the braking pressure, even when your feet are removed from the peddles. Beware that if you haven't got sufficient barking effect, pushing the brake peddles further will not affect it unless you open the valves again.
We found that by removing the handle of one of these valves and rotating it by 180 degrees, it gives better access to control the valves.
They used to use a red Berringer parking brake unit with a single lever, but it proved problematic.
Filling and bleeding the brakes can be a bit of a faff. It may seem unconventional, but the described method of filling from the bottom is the best way to complete this.
With various bits of tube, we adapted the tube on a syringe to fit the brake bleed nipple on one slave cylinder and filled the system by injecting clean brake fluid upwards.
The parking brake valves must be marked for their method of operation.
NOTE: We recommend these valves are only used as a parking brake. Do not use when doing power checks - if you do not have sufficient braking pressure in them and the plane creeps forward, further pushing the brake peddles will have NO effect.
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