The brakes on my Long are standard Cleveland brakes, mated to 5 inch wheels. The braking system has used DoT 5 brake fluid since the plane first flew in 1995. The brakes are not as good as I would ideally like (you certainly cannot lock the wheels under braking_) but they are reasonably effective, and I have only once experienced brake fade - after landing downhill at Sedona several years ago, the brakes faded at the very end of the rollout (although I still comfortably made the last intersection of the runway).
I would like to replace the brakes with Grove brakes at some point, because the Groves have greater braking power, and also appear to be of a higher quality than the Clevelands, but this is a future project.
Based on my experience since I bought the plane, the life of caliper piston o-rings is no more than 5 years when using DoT 5. (see other postings about the Marco Island incident and the caliper piston incident to answer the question: how do I know this?). The o-rings were last replaced 4 years ago.
I finished working on the plane yesterday to fit the new intercom, and it was time to go for a test flight. My pre-flight checklist includes an item when I get in the plane to perform a brake pedal test (see a future "True Confessions" posting for why I do this).
When I sat in the plane and tested the brakes, both pedals felt spongy. This, at the very least, means that there is air in the system. The brakes on my plane do seem to accumulate small bubbles in the caliper area over time, especially if the plane is not flown for a while. I assumed that this was the issue, which would require a brake bleed.
I pulled the plane back into the hangar, and removed the wheelpants. It was immediately apparent that the caliper pistons were probably leaking - the accumulated brake dust around the caliper body was moist on both brakes. This dust should be dry and easily removable.
When I removed the calipers and brake pad assemblies, I found that both pistons were leaking past the o-rings ; the brake pads and backing plates were wet. Additionally, the right hand pads were worn down almost to the point where the rivet bases were flush with the pad surface, and the left hand pads were almost as worn. The Annual Condition Inspection is due up in June, but this was maintenance work that needed to be done before I could take to the air.
I replaced the o-rings in both caliper pistons, and replaced the brake pads. This does not take a lot of time once you have done it once or twice. I also found a new technique for bleeding the calipers after replacing the o-rings, which I believe to be as effective as a bottom-up brake bleed. (This technique will appear in a future Central States newsletter).
After 1 1/2 hours of unplanned work, I was able to get in the plane, press the brake pedals, and get a nice solid feeling from the brakes.
I bedded in the brakes by performing stops from a slow taxi, and then performing 3 sudden stops from fast taxi speed on the runway. I also performed a rapid stop on landing after my test flight. The brakes are now bedded in, and feel pretty effective (as effective as the standard Clevelands can be on this plane). Brake pads that are not bedded-in result in a "springy" brake pedal, where a lot of pedal force is required to achieve good braking.