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Filling and bleeding newly installed brakes?

supercub

MEMBER
Let me check my GPS, gee how'd we ever navigate w
Have stock Scott master cylinders and Cleveland Wheels and Brakes. The brakes are installed with the bleeders on top and the brakes lines on the bottom. What's the best way to fill this system and then to bleed it? Thanks for your input.
 
Have stock Scott master cylinders and Cleveland Wheels and Brakes. The brakes are installed with the bleeders on top and the brakes lines on the bottom. What's the best way to fill this system and then to bleed it? Thanks for your input.

First, swap your calipers to get the bleeder valve on the bottom and lines on the top.. Pump fluid from the bleeder up to the MC.. Some guys use a modified week sprayer, I use a pressure pot.. Need rags under those stock MC's to catch the fluid that will overflow them.. Optionally you can set up some type of fitting with a hose attached run to a catch jar..

Brian.
 
Have stock Scott master cylinders and Cleveland Wheels and Brakes. The brakes are installed with the bleeders on top and the brakes lines on the bottom. What's the best way to fill this system and then to bleed it? Thanks for your input.

Vaccuum on top. Piece of tygon or vinyl hose connected to bleeder and then into a can of 5606 at the bottom.


Tim
 
I just did this yesterday, though I've got Steve's boosters now. I bleed with pressure from the caliper. My bleeder screw is on top of the caliper like yours and I have no problem with air entrapment. This fitting makes it a 10 minute job. The Steve's boosters have a reservoir that makes it easy to see when the fluid is running clear with no bubbles. When I had the stock master cylinders, I just jammed a clear vinyl tube (1/2" OD?) into the fill holes and collected the excess in a jar.

06-11414.jpg
 

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Each system is slightly different. There is a Super Cub in the fleet with Cherokee calipers and North masters that is incredibly difficult to bleed, even with a pressure pot. I even went so far as to set up a simulator with an identical caliper and a Grove master - no problem with a silly oil can.

I can only guess that there is an expansion loop inside the gear leg. Fabric is starting to fail; we shall soon know!

My personal Cub had stock masters, and all I did was fill the empty system from the bottom. Air free! But when I changed to Grove masters, I had to add a bleeder screw at the highest point on the master. If I let fluid get low, cracking that bleeder under pressure renders a rock-hard pedal.
 
First, swap your calipers to get the bleeder valve on the bottom and lines on the top.. Pump fluid from the bleeder up to the MC.. Some guys use a modified week sprayer, I use a pressure pot.. Need rags under those stock MC's to catch the fluid that will overflow them.. Optionally you can set up some type of fitting with a hose attached run to a catch jar..

Brian.

I wonder how come the Cleveland 6” conversion drawing has them on the top?
76c3a3bbd49b7ec0a46f38fb326b0cff.jpg



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Looked funky to me to. Did see it on others planes and thought it was an aviation thing. Maybe a question for SP.
 
I don't know for sure but it most likely falls into the category of that is how we where trained. If you look at a lot of the original covered gear legs on most planes the brake line came out at the bottom by the axle. If your line comes out the bottom and then you make a loop to the top with bleeder pointing down now you have created a great area for air entrapment. If you put the bleeder up air can come out the bleeder or work its way up to the master cylinder and escape there. So that would follow the picture and work. If you have uncovered legs mount with the bleeder down, throw out the 90 degree AN fitting on top and put in a 45 degree fitting so the line always go's uphill. Now without making a big loop to trap air run the line up to the master. Now the system wants to bleed itself. The final part can be tricky because some have that 40 year old rubber line wrapped around everything under the floor.
DENNY
 
I wonder how come the Cleveland 6” conversion drawing has them on the top?
76c3a3bbd49b7ec0a46f38fb326b0cff.jpg



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Beets me... never liked that... make more sense to have the line on top so air can not get trapped in the caliper... figure it’s a minor change to the Cleaveland drawing..

Brian


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I wonder how come the Cleveland 6” conversion drawing has them on the top?
That is a conversion drawing. The original brake line inside a covered landing gear V was a copper tube, the end of which is shown just below the axle with a 90* fitting. The new connector tube is that S shaped one on the bottom. IF the new connector tube went from that 90* fitting to the top of the brake you would have a loop which could trap another air bubble. This would become an even greater pain in the....

This design can be bled by first pressure feeding from the bleed valve up to the original master cylinder until full. Replace the master filler cap. Remove pressure pot, replace with clear hose to a can of fluid. Push brake pedal, turn on (close) parking brake valve, then release brake pedal, remove filler cap, top off master cylinder and replace filler cap. Open parking brake valve. Apply pressure to brake pedal while watching air bubbles at wheel brake. Apply parking brake. Release brake pedal, refill master etc. Repeat until there are no more air bubbles.

Not enough pedal after all air bubbles are gone? Apply brake, set parking brake, top off master, replace cap. Release park brake. Don't over do this as your brakes can become locked.
 
That is a conversion drawing. The original brake line inside a covered landing gear V was a copper tube, the end of which is shown just below the axle with a 90* fitting. The new connector tube is that S shaped one on the bottom. IF the new connector tube went from that 90* fitting to the top of the brake you would have a loop which could trap another air bubble. This would become an even greater pain in the....

This design can be bled by first pressure feeding from the bleed valve up to the original master cylinder until full. Replace the master filler cap. Remove pressure pot, replace with clear hose to a can of fluid. Push brake pedal, turn on (close) parking brake valve, then release brake pedal, remove filler cap, top off master cylinder and replace filler cap. Open parking brake valve. Apply pressure to brake pedal while watching air bubbles at wheel brake. Apply parking brake. Release brake pedal, refill master etc. Repeat until there are no more air bubbles.

Not enough pedal after all air bubbles are gone? Apply brake, set parking brake, top off master, replace cap. Release park brake. Don't over do this as your brakes can become locked.

Otherwise known as a PITA. Reverse the calipers so the bleeders are on the bottom. You’ll be happy you did.

MTV
 
FWIW the Cleveland STC drawing for my C180 show the bleeder on the bottom.

cleveland drawing 50-36.jpg
 

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Otherwise known as a PITA. Reverse the calipers so the bleeders are on the bottom. You’ll be happy you did.

MTV
If you do, make sure that the line goes uphill all the way. Make certain that you don't leave a loop or hump where an air bubble can easily become trapped. This can make for a forever spongy brake and a frustrated pilot. Rework the original copper tube and cut some fabric at the lower end of the gear.

I know, those of you who are in or from Alaska don't realize that Piper covered the gear Vs. 8)
 
If you do, make sure that the line goes uphill all the way. Make certain that you don't leave a loop or hump where an air bubble can easily become trapped. This can make for a forever spongy brake and a frustrated pilot. Rework the original copper tube and cut some fabric at the lower end of the gear.

I know, those of you who are in or from Alaska don't realize that Piper covered the gear Vs. 8)

Pete,

Thats why Alaskan pilots all carry knives......:lol:

MTV
 
My J-series airplanes have Grove and reservoir masters. The J3s have the bleeder up, the J4 has it down. The J4 is self bleeding and really easy to fool with.

One local SuperCub has one side up the other down. My Decathlon has them down, but a big Aeroquip flex line goes up and over the gear leg, then back down to the 30-19 caliper. I rarely have bleeding problems on my four. The Super Cub is the one that gives me an occasional problem.

I don’t really think it makes any difference if you know how to bleed brakes.
 
I just remembered something I had trouble with....
make sure the pistons on the brake caliper are pushed all the way into the caliper housing when installing.
Otherwise there's air in the piston bore, and no way to push it out of the system.
 
I have not used the “vacuuum” method. But I like the idea. It should “pull” all the air from the line.
 
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