Brake check?

[N941WR]

Originally Posted by Infidel

I'm still baffled with the left brake failure and left wing impact/damage. No flame here either, but having a hard time drafting it in my mind.

Lesson learned, never include the background that prompted the question, it causes way too much thread drift!

[Walt]

Originally Posted by N941WR

I called Cleveland AKA Parker Hannifin and was told to replace the O-rings in the master cylinders every 10 years. The O-rings in the calipers should be replaced every year, every two years at the most. The reason, I was told, is because of the heat build up in our small brakes can cause the O-rings to fail.

He mentioned that they consider 50 to 100 hours a year normal.

From my experience, O rings will start to seep/leak when they get old/hard from heat or age. They don't generally just "fail". Replacing them on a hourly or yearly basis seems like way overkill to me unless there are signs of leakage.
Every 5 years I might agree, but every year, I don't think so.

Some quotes from the Cleveland Maintenance Manual: (maybe the guy you talked to hasn't read their owm CMM)

Remove o-rings (8) from either pistons or cylinder. It is recommended that o-rings be
replaced at reassembly. However, if necessary, o-rings may be reused if not damaged,
cut, or deteriorated.

Replace o-rings with o-rings of corresponding part numbers. If necessary, o-rings may be
reused in the same position from which they were removed if not damaged. Inspect o-rings
for cuts, nicks, distortion, or excessive wear. Check to be sure o-ring has not become brittle.
Refer to o-ring removal procedure in paragraph 2B (1)(h).

[rightrudder]

Originally Posted by flyboy1963

after a brake rebuild, do you have to break the pads in with long taxi's, or hard braking on a couple of landings? I would hope deficiencies would show up there.

I would do a few hard-ish stops either while taxiing or landing to promote some pad material transferring to the rotor surface. You don't want to overdo it, because as stated earlier, we have tiny brakes and not a ton of cooling airflow if the wheel pants are fitted.

Good stuff on bedding, transfer layer, etc. here from StopTech:

http://stoptech.com/technical-suppor...ake-pad-bed-in

[David Paule]

Originally Posted by Walt

From my experience, O rings will start to seep/leak when they get old/hard from heat or age. They don't generally just "fail". Replaceing them on a hourly or yearly basis seems like way overkill to me unless there are signs of leakage.
Every 5 years I might agree, but every year, I don't think so.

Ditto. My experience is that the pads wear out well before the o-rings are close to failing, and that's a good time to check the system and replace things that need it.

On a time basis, o-rings seem to last considerably more than five years, even with heavy landing usage.

Dave

[Infidel]

Originally Posted by N941WR

Lesson learned, never include the background that prompted the question, it causes way too much thread drift!

Being a retired Police Offier, Its my nature.

[RV-4]

Well I'm glad this thread is been discussed as I've had a few issues lately with my brakes on my RV-4.

Will anybody know the Part number for the Piston O'Ring ( Cleveland ) for an RV-4..I looked everywhere but can't find it

Also are some better than others??

Thanks

Bruno
rv4@videotron.ca

[RV6_flyer]

Originally Posted by N941WR

No flame here either but the question is, how do we inspect our brakes properly? Inspecting and replacing our linings is easy but how do I know if the puck and O-rinngs are in good shape? Should we rebuild ours every X hours or Y years?


(His O-ring split.)

I have seen leaks start where you can see brake fluid around the calipers leaking past the O-Ring seal.

IMHO, they should be replaced every 5-years or 1,000 hours. I have seen several fail from age and also from time in service.

Just my experience and others may vary.

My RV-6 will have been flying for 18-years and 3,010+ hours next month.

[RV6_flyer]

Originally Posted by RV-4

Well I'm glad this thread is been discussed as I've had a few issues lately with my brakes on my RV-4.

Will anybody know the Part number for the Piston O'Ring ( Cleveland ) for an RV-4..I looked everywhere but can't find it

Also are some better than others??

Thanks

Bruno
rv4@videotron.ca

Info on the brake o-ring can be found here.

[BCP Boys]

Originally Posted by N941WR

No flame here either but the question is, how do we inspect our brakes properly? Inspecting and replacing our linings is easy but how do I know if the puck and O-rinngs are in good shape? Should we rebuild ours every X hours or Y years?


(His O-ring split.)

These O rings are cheap... I keep 2 new ones in my hanger all the time. I replace them at least once every year. A little of my time and and a few bucks.... Truth be told, when I moved over to my -7, I had never flown tail draggers in my life. Ironically I flew a 310 for 13 years.... and when I was training and learning (still learning) to fly, land and taxi a tail dragger, I was dragging my feet on one of the brakes and one of the o-rings got too hot and leaked out all the fluid. Luckily for me it was after I put the plane up in the hanger. After taking the puck out to inspect it I found a nice FLAT O-Ring around the puck.
I can laugh at myself now but I learned a couple of things from that experience:
1. The O-ring is cheap and easy to replace.
2. It is one of those CRITICAL items that costs nothing compare to what's it's job is.
3. When it fails, I'm having a bad day.
4. And oh yeah, place my feet on the outer frame of the pedals while taxing.

Moral of the story: May not be something that you check often right now, but it is a critical item that costs very little and gives you a piece of mind.

[AndyRV7]

Very timely for me. I took my plane to it's first condition inspection yesterday and when I pulled the wheel pants, there was brake fluid on the inside of the passenger side one, on the brake side of the wheel. No signs of drips or fluid on the tire and no change in funtionality. Sounds like I was about to have a bigger problem. Great discussion.

PS. I ordered a half a dozen o-rings this morning.