C182P Brakes Question

AggieMike88

AggieMike88

Touchdown! Greaser!
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The original "I don't know it all" of aviation.
I took an opportunity to attempt a lunch time flight in the club 182P

But it was a no go when after start, the brake check found that the right pedal brake had zero resistance. Left okay, but right went to full deflection.

Shut down, put plane back into hanger. Starting looking and feeling around.

There were puddles on the floor. Reaching behind the pedal, I identified the brake cylinder, but it, the rod, and what area I could reach behind and below it was dry. Pedal feels like there is no fluid in the system, but I didn't discover where it had gotten to.

A call to the pilot who used it before me found no issues when he flew it 10 days ago.

Any ideas of what might have happened?
 
Fill it back up, pump the brake and see where it leaks. I fill them through the bleed valve pumping the fluid up to the cylinder.
 
Were were the puddles on the ground? Under the fuselage? Under the brake caliper? Once you find where its coming from, you will have you answer. Its not uncommon to have a caliper o-ring or such go bad on you. Most likely it started on previous flights, but it was not noticed until the fluid got low enough to become an issue.
 
flyingmoose said:
Were were the puddles on the ground? Under the fuselage? Under the brake caliper?
Click to expand...

No to all 3. Which added to the mystery.

Once you find where its coming from, you will have you answer. Its not uncommon to have a caliper o-ring or such go bad on you. Most likely it started on previous flights, but it was not noticed until the fluid got low enough to become an issue.
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I've squawked it to the MX officer who's gonna get it fixed tomorrow.

Just a bummer since today was a very very nice day to go fly.
 
AggieMike88 said:
No to all 3. Which added to the mystery.



I've squawked it to the MX officer who's gonna get it fixed tomorrow.

Just a bummer since today was a very very nice day to go fly.
Click to expand...

Is it a fluid level problem or did you just lose the seals in the master cylinder?
 
Oh, you said in your first post that there was a puddle on the ground. Either way, if there is no puddles then a couple of things could be happening: if the oring is leaking on the caliper then it will leak when you are braking and will slowly leak out on the taxiway and you will never notice, other one is its leaking in the belly. Either way its for MX to find, but just my 2 cents.
 
My mistake... no puddles.
 
Henning said:
Is it a fluid level problem or did you just lose the seals in the master cylinder?
Click to expand...

Not sure yet. If the master cylinder is the small cylinder just behind the pedal, then that's the one that no resistance. Even when pumping it.

When the MX officer reports what he fixed, I'll share.

The last 2 weeks of April, this aircraft is scheduled for it's annual. I'm thinking of taking some time off and helping the mech unbutton everything and assist with other chores. It's a very nice Skylane and I'd like to learn more about what goes on "behind the scenes".
 
AggieMike88 said:
Not sure yet. If the master cylinder is the small cylinder just behind the pedal, then that's the one that no resistance. Even when pumping it.

When the MX officer reports what he fixed, I'll share.

The last 2 weeks of April, this aircraft is scheduled for it's annual. I'm thinking of taking some time off and helping the mech unbutton everything and assist with other chores. It's a very nice Skylane and I'd like to learn more about what goes on "behind the scenes".
Click to expand...

That's the one. If there is NO resistance, it's likely out of fluid. The whole system is dirt simple.
 
Gotta go with Henning on that. Not much going on there at all. Cessna 182 brakes aren't even as interesting as the drum brakes on my old '68 Chevy Van when I was a kid. Cylinder, rod to pedal, pressure, brake fluid hydraulic line to the wheel assembly/caliper, squeezes brake pads. The parking brake just pulls on a cable that pushes the pedals down.
 
There's a small Lock-O-Seal washer in the master cylinder that acts as a check valve between the piston rod and piston. When you apply the brakes, that seal closes the return to the master's reservoir and allows the piston to build pressure. That seal can fail and the piston will go up and down and do nothing for you.

I bet the rubber seals are all old, both in the master and in the caliper, and the hoses at both ends are likely shot due to age as well. The mechanic might find a bit of oil puddling inside the belly. If it leaks over time, it gather dust and makes sticky sludge that plugs drain holes and prevents it draining out onto the belly skin where you can see it.

Dan
 
Dan Thomas said:
There's a small Lock-O-Seal washer in the master cylinder that acts as a check valve between the piston rod and piston. When you apply the brakes, that seal closes the return to the master's reservoir and allows the piston to build pressure. That seal can fail and the piston will go up and down and do nothing for you.

I bet the rubber seals are all old, both in the master and in the caliper, and the hoses at both ends are likely shot due to age as well. The mechanic might find a bit of oil puddling inside the belly. If it leaks over time, it gather dust and makes sticky sludge that plugs drain holes and prevents it draining out onto the belly skin where you can see it.

Dan
Click to expand...

And is a freaking nightmare to clean up lol. I used to shred my arms doing that through those access holes.:nonod:
 
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