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Brake leak out

P

pauldan181

Well Known Member
It was a perfect day for flying so I left work early, went to the hangar and found this....

2czjtw.jpg


Anybody have the MS # for the brake puck O-ring handy?

Paul Danclovic
Jamestown NC
RV-8A N181SB
 
O-Ring

MS28775-218 spruce pn=101-02300 http://www.aircraftspruce.com/catalog/lgpages/500x5brake.php
Make sure it's not a crack in your brake line. If it is call Bonaco for braided steel lines.

RAPCO RA66-106-4K BRAKE LIN KT spruce pn=06-00651 http://www.aircraftspruce.com/catalog/lgpages/rapco_brklinig2.php

If you have a Hand Rivet Squeezer get this: http://www.averytools.com/prodinfo.asp?number=4625

Remember the pucks can be put in the wrong way and cause a bad day. Make sure they go back in like this, o-ring side goes in first.

IMG_00649.jpg
 
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Thanks for the info guys, I've got some O-rings on the way.

I just replaced the brake pads a few monthe ago and the I'm going to make new lines from the brake up to the fuse even though the line was totally dry. It looks like the fluid was leaking out of the piston.

Paul Danclovic
Jamestown NC
RV-8A N181SB
 
This is unusual - not a normal wear problem

The fact that it is the left brake is unusual - it is the right brake that is often pushed during takeoff and wears prematurely when right rudder is applied.

Which piston are you talking about when you say it looks like it is coming from the piston? If it is the piston in the slave cylinder near the wheel the piston may have been installed backward (the company - Cleveland - even had a production run where pistons were installed backward and thay issued a service bulletin or AD for correction). The brakes work fine at first but as the pads wear down the O-ring comes clear of the cylinder enough to provide a leak path.

The O-ring sometimes comes from the factory damaged in assembly - I had one of those. This of course allows leakage.

I had a new master cylinders at the rudder pedals with weak return springs whick allowed fluid to come out of the top (back) of the master cylinder. Stretched the springs and reinstalled fixed that problem.

I had a new master cylinder with a factory assembly damaged O-ring which leaked fluid every time that brake was applied - deposited red brake fluid on the red carpet.

If your O-rings are the original equipment a MS O-ring with slightly different dimensions may have substituted for an AN O-ring which then leaks under pressure. Your leak does not appear to be a leak that only occurs under pressure.

If the cylinder walls are scarred the fluid could leak there.

I can not think of a leak involving the line unless it is cracked or broken at the flare, or the fitting is not properly installed or tightened.

Bob Axsom
 
me too

Hello and welcome me to the world of aircraft ownership! Just bought a 9A yesterday. My issue. Yesterday the right brake was leaking. He told me they had did the left brake 2 months ago. He said he should have done the right one at same time. He put in a new seal and away I went. 3 hrs later, (and a bit of a firm landing with some hot tires) parked and this morning, the left brake is leaking. Took off fairing and with a light, confirmed coming from up inside, and I'm assuming it's the oring. (same issue as yesterdays right brake puck) Pads are new.
Is this an on going issue with these? If I'm applying too much brake, is it going to leak...afterall, I'm on a shorter runway and I will be using the brakes. Please advise. I'm not about to go into the brake repair business.
Thx, DM
 
Search the archives for "viton o-rings" and "83282"

This is a known issue with brakes, not just on the RV. Quick and easy fix.
 
flyeyes said:
Search the archives for "viton o-rings" and "83282"

This is a known issue with brakes, not just on the RV. Quick and easy fix.
Click to expand...
i'll read/search later. For now, can you at least tell me that I need to order some parts? I want to get these underway. Er uh...so does these mean I gotta carry a brake kit with me, with a bleed kit? good grief :p
 
Short version...the supplied disk/caliper combination has a marginal kinetic energy rating for an aircraft with this speed and weight. Don't take my word for it; the calculation (from FAR 23.735) is simple. Repeated full stop landings on a very short strip do not allow time for the disks and calipers to cool.

Throw in some unintended brake dragging during taxi, or just too much brake steering and things get really hot. The stock nitrile o-ring has a rather low temperature rating, above which it gets charcoal-hard and useless. Brake fluid leaks out onto the hot disk inside the tight RV wheelpant. A leak while parked is merely an inconvenience. The flash point of standard MIL-H-5606 is low enough that more than one airplane has caught fire on the taxiway.

The suggested viton o-ring has a temperature rating about 175F higher than a nitrile o-ring. 83282 fluid has a flash point more than 200F higher than 5606 fluid.

Brake disks are a heat storage media. Disks with more mass store more energy at a lower overall temperature. The energy (heat) is released back into the air over time. Cleveland sells an upgrade kit with thicker disks. You don't absolutely need thicker disks, but they improve an A-model which is used in windy climates and/or subject to long taxi times.
 
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I just installed the Rapco discs.... spruce p# 06-01311 $88.90 each. They are about 50% thicker than stock. Made spacers and used longer bolts. Saved over $250.00. Cleveland kit was $432.95
 
DanH said:
Short version...the supplied disk/caliper combination has a marginal kinetic energy rating for an aircraft with this speed and weight. Don't take my word for it; the calculation (from FAR 23.735) is simple. Repeated full stop landings on a very short strip do not allow time for the disks and calipers to cool.

Throw in some unintended brake dragging during taxi, or just too much brake steering and things get really hot. The stock nitrile o-ring has a rather low temperature rating, above which it gets charcoal-hard and useless. Brake fluid leaks out onto the hot disk inside the tight RV wheelpant. A leak while parked is merely an inconvenience. The flash point of standard MIL-H-5606 is low enough that more than one airplane has caught fire on the taxiway.

The suggested viton o-ring has a temperature rating about 175F higher than a nitrile o-ring. 83282 fluid has a flash point more than 200F higher than 5606 fluid.

Brake disks are a heat storage media. Disks with more mass store more energy at a lower overall temperature. The energy (heat) is released back into the air over time. Cleveland sells an upgrade kit with thicker disks. You don't absolutely need thicker disks, but they improve an A-model which is used in windy climates and/or subject to long taxi times.
Click to expand...
i will assume it was my high energy stop and taxing, that failed the oring. these are cleveland brakes. is there a different better o-ring...and then put in the higher temp oil? I'd rather not go $600 on a matco wheel/tire assy.
thank you for the info. I need to order some parts and I'm gonna wait for a response. DM
 
DanH said:
You don't absolutely need thicker disks, but they improve an A-model which is used in windy climates and/or subject to long taxi times.
Click to expand...

This is exactly the scenario that contributed to the leak out in the original post.

Long taxi, >2 miles, stuck behind a slow moving Cessna on a windy day. I put the plane away everything was fine. A couple of relatively cold nights, (piston shrinkage?) the o-rings gave it up and all the fluid was on the floor.

Good post Dan

Paul Danclovic
Jamestown NC
RV-8A N181SB
 
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drmax said:
i'll read/search later. For now, can you at least tell me that I need to order some parts? I want to get these underway. Er uh...so does these mean I gotta carry a brake kit with me, with a bleed kit? good grief :p
Click to expand...

drmax said:
i will assume it was my high energy stop and taxing, that failed the oring. these are cleveland brakes. is there a different better o-ring...and then put in the higher temp oil? I'd rather not go $600 on a matco wheel/tire assy.
thank you for the info. I need to order some parts and I'm gonna wait for a response. DM
Click to expand...
This is my first post and I hope it's useful. A 3 minute search (using the "search" function) revealed these findings......

VAF verification

V90 brake caliper o-ring - O-Rings, Inc.

V75 brake caliper o-rings - O-Rings, Inc.
 
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can i just drain and replace the 5606 or does it need flushing?
also, is all the other rubber or plastic components withing the system compatible with this other higher temp oil? I.E. master cyclinder?
Thank you.
 
drmax said:
can i just drain and replace the 5606 or does it need flushing?
also, is all the other rubber or plastic components withing the system compatible with this other higher temp oil? I.E. master cyclinder?
Thank you.
Click to expand...
If your going with the higher temp fluid then you should definitely flush the entire system of the old type.
Mike S said:
Richard, welcome to the good ship VAF.

Yes, it is useful, thanks for doing the leg work.

Good to have you aboard.:D
Click to expand...
;) Thanks Mike! Looks like I've found a new home!:D
 
FreeFly'r said:
If your going with the higher temp fluid then you should definitely flush the entire system of the old type.

;) Thanks Mike! Looks like I've found a new home!:D
Click to expand...
need more info for the oil, other than higher temp. would be devestating to dump something in there that would eat up other parts.
i'm send a request to Spruce to supply the nitron type seals.
 
drmax said:
need more info for the oil, other than higher temp. would be devestating to dump something in there that would eat up other parts. I'm send a request to Spruce to supply the nitron type seals.
Click to expand...

MIL-H-83282 fluid is entirely compatible with MIL-H-5606 fluid. Either fluid is entirely compatible with both nitrile and viton seals. Aircraft Spruce does not sell viton seals, but merely reading the previous posts, or learning how to use this forum's search functions, or a quick Google will provides leads to a source for both fluid and seals.
 
^This. I also edited my first post with more precise links. Just tryin' to keep people from going too far astray. ;)
 
FreeFly'r said:
^This. I also edited my first post with more precise links. Just tryin' to keep people from going too far astray. ;)
Click to expand...
Cool deal. I earlier "googled" and ordered 6 V75's and 2 qts of the higher temp oil, with plans on changing it all out this weekend. Thx for your work! Dm
PS. I sent a message to one of Spruce's men to see about stocking these parts...i.e. Vitron orings and the oil.
 
By the way, inspect the cylinder and piston when you replace them; when this happened to me, I found a nasty scratch that required a brake replacement. I was unable to determine if the scratch was a manufacturing defect that had caused the O-ring to fail (at about 60 hours) or if the O-ring failure had led to the scratch. Either way, I've inspected at 2 annuals since then and no further problems.
 
Been there also

I had this happen a couple of years ago when at the Arlinton flyin. This can be kind of a dangerous issue if it goes un-noticed like mine did as we were parked in the grass so none of brake fluid showed up on the ground like yours did. Flew out of there and into Salem Oregon and landed without braking, there must have been just enough fluid left when we took off that it did not show up until after take off when the rest leaked out. As they say timing is everything. We were able to get stopped before the end of the runway, and pull the plane into the FBO where they helped me repair and replace the brake pads, and O rings and charge the brake lines again. But be careful and inspect your brake pads often. I have had no issues since I added the push springs to the brake pedals, the brakes were not releasing far enough to not create heat and wear even when not being used, but now all is fine. So this is just a caution to those that have not seen this as yet. Glad you were lucky and found this issue in your hangar. Other than the disapointment of not flying that day, at least you were safe.
 
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