Brake care and feeding

[Roger Lee]

Hi Guys,

 

Just a little note on checking your brakes. First make sure if you or your mechanic uses any fluid it should be :

AEROSHELL BRAKE FLUID

Petroleum-base hydraulic fluid for use with brake and hydraulic systems with synthetic rubber seals. Meets specification MIL-H-5606G. Colored red

 

 

 

Do not use any automotive fluids like Dot 4. These fluids will eat your seals, “O” rings and brake lines and cause more leaks than the Dutch Boy can plug, not to mention a little drain on the wallet. To start you should not have to pump your brakes. If you have to pump them they may eventually fail and it may not be pretty after you get stopped up against you friends hanger wall. One pull of the brake lever 1” or 2” and they should be firm. The parking brake when set ought to hold over night if need be. I do not recommend though that you use your parking brake for long term parking. For an hour type thing for a restaurant break is fine, but for long term parking get a nice set of wheel chocks. The brake fluid reservoir should only be about ½ full. If you try to top it off and then apply the brakes you will have some fluid over flow from a slight back flow to the reservoir when the brake is applied. Check the brake fittings every now and then and look for any leaks in the tunnel floor under the master cylinder and around the fittings at the caliper. Take a flashlight and look down into the caliper gap at the brake pads and see if you have any pad left. On the Matco’s you have a notch in the pad itself and when the wear gets down to this point it’s time for new pads. Make sure you never get any type of lube, oil, silicone, WD40, grease or anything along that line on a brake pad. Depending on what you got on it might be savable, but sometimes you just have to toss them and put in new.

 

Your brakes ought to be good enough to hold your plane at full throttle and not creep forward. I will say one thing about the Italian brakes, when they get hot they have brake fade and the Matco master cylinder puts out almost double the pressure. The Italian brake disc rides on 4 pins. These get very dirty and the disc won’t side very well over them. You may need to remove these pins during an annual and clean them with a little cleaner and some 360 grit sandpaper. This should make them smooth again. Clean them don’t sand them down to a nub. If you live in a very humid or wet climate the disc on either brake set can get a film or even glaze over a bit. You can clean these with a little lacquer thinner and some 360-400 grit sandpaper to help de-glaze and clean the surface.

 

 

add on:

A quick and dirty way to check your bearings/axle mounting without having to remove the wheel is to lift the wheel off the ground and set the axle on a block. The grab the wheel and try and move it back and forth. Your looking to see if there is any free play. It should be tight and no free play. If there is free play then you need to remove the wheel and find out why the free play is there. Maybe a bad bearing or maybe just a loose axle nut, but any free play should be investigated.