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More brake woes

Flying Canuck

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I?m on a big cross county trip, visiting family in Summerside, PEI, 2400 NM from home. It?s been a good trip,, RVs are a great way to travel. I had 3 weather related diversions, but never got into much trouble. My first day last Saturday had me lose all of my brake fluid on the right side after landing. This was resolved after we found a broken flare in the top of leg fitting. Brakes worked great until yesterday. After a couple of short flights here I noticed my right brake was gone on rollout. After a half dozen left hand pirouettes for my right exit I had to shut down to stop turning. Got a tow back to the hangar and got a look today. I set out to bleed the brake and quickly discovered when my son pressed on the brake that fluid was coming out around the piston. No standing leak, but I had lost some fluid earlier at the end of the runway.

We removed the calliper and I got the piston out. There were no signs of any problems, not in the calliper, nor the piston or o-ring. Everything was nice and smooth. We?ll reinstall it tomorrow and check agin, just in case there was something contaminating the seal. I am not optimistic, I have always had problems with this brake leaking occasionally. I suspect there may be a non-visible defect in the assembly. Anyone else see this?

I?ve got Marco callipers, and less than 100 hours on them.
 
Had nothing but problems with my Matco masters. We bled the brakes what seemed like 5 times a year, then we had leaking out the shaft. Rebuilt and polished shaft but still no good.

We just recently put in Grove masters with built in reservoir. Wow, what a difference. Adjustable throw so we could pitch the pedal back a bit, more brake power, feel better than old ones ever did.
 
Marco Brake Calipers

I?m on a big cross county trip, visiting family in Summerside, PEI, 2400 NM from home. It?s been a good trip,, RVs are a great way to travel. I had 3 weather related diversions, but never got into much trouble. My first day last Saturday had me lose all of my brake fluid on the right side after landing. This was resolved after we found a broken flare in the top of leg fitting. Brakes worked great until yesterday. After a couple of short flights here I noticed my right brake was gone on rollout. After a half dozen left hand pirouettes for my right exit I had to shut down to stop turning. Got a tow back to the hangar and got a look today. I set out to bleed the brake and quickly discovered when my son pressed on the brake that fluid was coming out around the piston. No standing leak, but I had lost some fluid earlier at the end of the runway.

We removed the calliper and I got the piston out. There were no signs of any problems, not in the calliper, nor the piston or o-ring. Everything was nice and smooth. We?ll reinstall it tomorrow and check agin, just in case there was something contaminating the seal. I am not optimistic, I have always had problems with this brake leaking occasionally. I suspect there may be a non-visible defect in the assembly. Anyone else see this?

I?ve got Marco callipers, and less than 100 hours on them.

Is their a chance the pistons were installed backwards when last assembled into the calipers? The O-Ring end of the piston must be installed first into the caliper.
 
Glad to see you are getting lots of usage of your 9.
Caliper orings can loose their seal as they stiffen up & loose their round shape in the bore. Best to replace it if you already have it apart. O ring is same as used on a number of certified a/c so maybe the local mechanic has one.
 
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The o-ring in this calliper is in the bore, not the piston. There is no perceptible direction for the piston, it?s just a straight cylinder. I?ve reinstalled it in the same orientation as original based on the slight wear on the face. The o-ring is embedded in the bore wall and has a flat inside surface that is flush with the wall. There are no aviation mechanics at this field.

I?ll test it out today now that it?s reassembled. Maybe I can find an AME in Charlottetown with an o-ring. Otherwise, if it still doesn?t seal, I?ll have to order something on Monday for overnight delivery. I need to be on my way home by Wednesday or Thursday latest.
 
And now that I think about it, the M3-222 Buna-n o-ring seems to be the correct one for my calliper (PH-1A). This is a round cross section ring, I sure shouldn?t be seeing it flat and flush with the bore wall. I?ll try to find a suitable o-ring and replace it.
 
O-rings

I have had several leaks at the brake cylinders (both sides). I finally replaced the factory O-rings (Buna) with Viton rings and so far no more leaks. My -8 has Matco brakes PH-1A. The calipers came with Buna rings-part number MSC2-222. The Viton part number is 222VBN. Buna rings are black, Viton rings are brown. I got them from Oringsandmore. Hope you get the issue resolved--I hate dealing with leaky brakes!
 
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I finally found an o-ring locally. It's a perfect fit but it probably isn't the exact part. There's no question that the original ring is deformed. I'll reassemble this afternoon and see how it seals. I ordered a couple of sets of the Viton rings that I'm getting shipped to my home, I'll replace both sides when I'm home. I'm also going to try to get myself setup for a field repair before I depart homeward. Getting the tire off will be the tricky part. I didn't bring my jack setup. If nothing else, my travel kit planning will be much better for future trips.
 
New o-ring is holding flawlessly. Took quite a while to bleed the brake and I've still got a soft right side pedal. The pilot pedal is solid. Suggests to me some air is trapped between the pedals, we'll go out tomorrow and try to get that out. The brake works now, all I'd like now is some confidence that the air in between the pedals isn't going to migrate past the pilot pedal and cost me my brakes again.

This is time confusing, tedious and frustrating stuff. I'm just glad my brake problems didn't show when I went through Burlington, VT - an airport that surprised me at how busy it was.
 
We just went through this issue on my buddies Cozy MKIV with 3 puck calipers. One of the pucks O rings had enough wear that the puck was able to angle enough in the cylinder to let the brake fluid blow by. We rebuilt both calipers with new O rings and replaced the puck that blew out due to it having some wear damage. This is the second time this happened on his Cozy with the Matco calipers.
 
New o-ring is holding flawlessly. Took quite a while to bleed the brake and I've still got a soft right side pedal. The pilot pedal is solid. Suggests to me some air is trapped between the pedals, we'll go out tomorrow and try to get that out. The brake works now, all I'd like now is some confidence that the air in between the pedals isn't going to migrate past the pilot pedal and cost me my brakes again.

This is time confusing, tedious and frustrating stuff. I'm just glad my brake problems didn't show when I went through Burlington, VT - an airport that surprised me at how busy it was.

Claude, The pilot masters get their fluid from the co-pilot side. As the braked wear down and require more fluid to take up pad wear, the air bubble might make it to your side...... but it will be a while.

On Cleveland brakes the "O" rings do have a round cross section when new, and that will pull the piston back a few thousands from the disc when the pressure is released. A flat side indicates wear and should be replaced.
 
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