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  #1  
Old 10-16-2007, 04:13 AM
wv4i wv4i is offline
 
Join Date: Jan 2005
Location: Palm Beach County, FL
Posts: 304
Default Cleveland Brake Piston Install Backwards

Know there's been thread either here or on Matronics, somewhere, about this condition, but it bears repeating. It is easily possible to install the piston in side out. Once brake pads wear a little, the O-ring will become exposed and a complete loss of brake fluid will occur without warning. This is because the O-ring is much closer to the in side face of the piston, about 1/8", than the out side face. Proper installation can be assured by backing off the 2 brake lining bolts about 1/8", have someone press the brakes. If piston extends by 1/8" and you cannot see the O-ring you are good to go. Sudden loss of one brake in a tailwheel airplane could really ruin your day. This check only takes a couple of hours at the most. Pictures or a pdf diagram may be helpful if some could post. Thanks.....

From Rosie: This thread discusses this and has pictures...
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Last edited by Rosie : 11-05-2007 at 10:40 AM.
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  #2  
Old 10-16-2007, 10:22 AM
hngrflyr hngrflyr is offline
 
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Location: eugene, oregon
Posts: 206
Default

That's proof that, if there is a way to do it wrong, someone will find it.
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  #3  
Old 10-16-2007, 06:44 PM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
Posts: 5,685
Default Well ... two comments

1 - The failure condition described will also happen with the puck in right if let the pads wear down enough.

2 - If you think a plane with a steerable tail wheel will be a handfull with the loss of a brake, can you imagin the situation in a plane with a castering nose wheel and a brake loss.

For example if you are standing still and the fluid has leaked out of one slave cylinder and you have an inocent looking wet area on the ramp inboard of that main gear; you start the engine and apply the other brake to pull out of the parking place and turn away from the fluidless brake; the nose wheel pivots to the stop - wow! what a ride. There is nothing you can do but cut the engine and wait for the rolling friction to overcome the mumentum and hope no one is parked on the side you are turning to. In a forward moving plane the rudder will provide steering and folks here have made me more aware of the need to use that and stay off the brakes when they are not needed. I still change the pads every year during the condition inspection.

Bob Axsom

Bob Axsom
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  #4  
Old 11-04-2007, 02:50 PM
kklewin kklewin is offline
 
Join Date: Jan 2005
Location: Bozeman, MT
Posts: 224
Default

I had this happen twice on my 6A...apparently they were installed backwards when they were shipped and I didn't catch it....took two failures for me to figure it out.....works much better now...

Kurt
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  #5  
Old 11-04-2007, 04:58 PM
DickDe DickDe is offline
 
Join Date: Apr 2006
Posts: 205
Default Brake Piston reversed

I recall about 5 years ago someone, Van's, Cleveland, a service letter, an FAA AD or some similar notice, had all owners of Cleveland brake kits check for reversed piston pucks which caused the O ring to blow out shortly after installation during brake pad break in. Some of the other builders may remember full particulars that I can't recall but a number of the kits came from the factory that way. I know of one builder that had the seal blow out within a few hours short of his initial flight.

Dick DeCramer
N500DD RV6 215hours
RV8 tanks
Northfield, MN
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  #6  
Old 11-18-2012, 05:12 PM
Lee Jordan Lee Jordan is offline
 
Join Date: Jul 2005
Posts: 33
Default

I know this is an old post, but I think this just happened to me today. I lost my brakes on one side and upon examination I could see brake fluid coming out of the caliper from the piston area. I took the caliper apart and I noticed the o-ring that goes around the piston was partially exposed. I thought this was odd because the brake pads had about half their material left.

I took the piston out and saw that the o-ring sits very near one side of the piston. As installed the piston would only need to travel about an 1/8 inch to push the o-ring out of the caliper. That just didn't seem right to me. I flipped the piston around, now the piston has to travel much further before the o-ring is exposed. I put everything together and did some taxi tests. The plane appears to be handling fine. The pedal is a little mushy, but I think I have some air to bleed out.

I called the last person that I believe worked on the brakes, and they are fairly certain that the piston was installed correctly. In other words, they believe the o-ring should sit close to the outside edge of the caliper. They insist that the piston travels very little.

I've tried to find a schematic for Cleveland brakes showing the piston orientation, but no luck so far. Which way does the piston fit inside the caliper? O-ring toward the inside of the caliper, or the outside?

Thanks,
Lee
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  #7  
Old 11-18-2012, 05:27 PM
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flyeyes flyeyes is offline
 
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Default

Quote:
Originally Posted by Lee Jordan View Post
Which way does the piston fit inside the caliper? O-ring toward the inside of the caliper, or the outside?

Thanks,
Lee
o-ring should be closer to the hydraulic fluid, farther from the rotor.

Also search for "viton o-rings" and "83282" for discussion on making your system more robust
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  #8  
Old 11-18-2012, 08:48 PM
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bhester bhester is offline
 
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Location: Hopkinsville, KY
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Red face O-ring position

As said the correct direction is furthest from the rotor. The person that worked on yours put it back together wrong according to what you have said. Pictures on my web site:
http://home.newwavecomm.net/bobbyhester/2012Flying.htm
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  #9  
Old 11-19-2012, 08:05 AM
Lee Jordan Lee Jordan is offline
 
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Posts: 33
Default

Thanks for the info and conformation.

-Lee
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