New Brake Linings

[AZOutlaw]

I have the dual puck brake system and typically replace brake linings every year at annual.  Each time we put the new brakes back on the plane, they are "locked up."  I can turn the wheel some (with great effort) but they are tight!  We looked this over and can't figure out why.  Anyone have this issue?  Do I need the shim insulators between the two plates?

One question on bleeding.  I did the pressure pot thing on my previous D model.  That system still work on an Ovation?

[StevenL757]

You don’t (or shouldn’t) need any shim insulators on Ovation brakes/linings.  Also, make sure you’re ordering the correct brake lining part# 66-105…preferably the four-packs (one four-pack for each of the two main struts).

https://www.aircraftspruce.com/catalog/lgpages/clevebrakelining4pk.php?clickkey=3016903

When changing linings, ensure both pistons inside each caliper are compressed flush to the inner caliper face throughout the process; else, the fit will be tight when you put the linings back on the calipers, and ultimately when you put the wheel back on.

[RLCarter]

If replacing the pads make the brakes drag, sounds like you have alignment issues, this is further reinforced by have having to replace pads at every annual 

[cliffy]

Are the pads worn out causing you to change them every year? If so you have a problem or you ride your brakes when taxiing

It might be time to remove the calipers and pull out the pistons and check things out 

Clean bores, new orings, fresh fluid in the cylinders might be helpful  Clean and polish the pins. 

If the calipers have never been off and rebuilt you might also have red jelly in the cylinders instead of liquid oil.. 

 

[AZOutlaw]

Thanks Guys, Pads are correct (but the Rapco Version) and calipers were removed to get new O-rings, and thus, compressed all the way in.  I don't replace pads every annual but most of the time as they are inexpensive and easy to do.  This year the seals leaked when it got cold so the pads were a mess and it needed a thorough cleaning/replacement.  The only thing I can think to look at is the rods ( I think the call them anchor bolts)  I'll pull them off and make sure they are shiny smooth and slide easily.  

[kortopates]

1 hour ago, AZOutlaw said:

Thanks Guys, Pads are correct (but the Rapco Version) and calipers were removed to get new O-rings, and thus, compressed all the way in.  I don't replace pads every annual but most of the time as they are inexpensive and easy to do.  This year the seals leaked when it got cold so the pads were a mess and it needed a thorough cleaning/replacement.  The only thing I can think to look at is the rods ( I think the call them anchor bolts)  I'll pull them off and make sure they are shiny smooth and slide easily.  

Sounds like your issue may be as simple as needing to lubricate the pins that the calipers slides back and forth on - what you referred to as the rods I believe. Suggest using some silicone DC4. They will often bind when your moving the plane by hand without them being properly lubricated.

You may be replacing the pads just to be safe, but with the dual puck brakes you should be able to get much more than a even a couple annuals of wear on the pads before replacing them. Unless perhaps you live on a very short field and need to really get on the brakes with every landing. But if your able to land, use aerodynamic braking (hold the nose wheel off as long as possible)  and exit with barely touching the brakes they should last you many years without replacing the pads. 

[OR75]

how often do you change the disks ? 

[Shadrach]

20 minutes ago, OR75 said:

how often do you change the disks ? 

I’m 99% sure that our disks are the factory originals that came with the airplane in 1967. Airframe has 3300 flight hours. The discs still measure well above minimum thickness.

We’ve had linings last for more than 1200hrs. I had one batch that only lasted ~500 hours but that was a period when I was going in and out of a lot of sub 2000 foot strips.

[Hank]

4 minutes ago, Shadrach said:

I’m 99% sure that our disks are the factory originals that came with the airplane in 1967. Airframe has 3300 flight hours. The discs still measure well above minimum thickness

I replaced my 1970 disc's two years ago. In 15 years, I've replaced pads twice, the joy of being based at a 3000' obstructed field.

Yes, I've learned better energy management and rarely use brakes at my current 5000' home. 

But the OP's Ovation is heavier than my C or Shadrach's F. But not that much heavier!!

[Shadrach]

4 minutes ago, Hank said:

I replaced my 1970 disc's two years ago. In 15 years, I've replaced pads twice, the joy of being based at a 3000' obstructed field.

Yes, I've learned better energy management and rarely use brakes at my current 5000' home. 

But the OP's Ovation is heavier than my C or Shadrach's F. But not that much heavier!!

If I’m going into a strip that actually requires brakes to make a turn off, chances are I’m at <2300lbs.

[AZOutlaw]

Thanks for the feedback.  It turned out to be a torque issue.  I took a few pictures of the new pads and they have very minimal clearance from the rotor. (like none!)  The specs called for 75 to 90 in lbs.  I'm always a more is better guy so I set the wrench at 90, and the wheels wouldn't turn.  Today I backed the bolts off and the wheels spun freely.  I then tightened to 75 in lbs and the wheels just started to stop free wheeling but would still roll.  All seems good and a couple of trips down a runway will have them free again.

I realize I change pads more than most of you, but an Ovation is quite a bit heavier than many of the planes out there too. (my last plane was a D)  My pads are typically good when I swap them out, but with some oil leaking they were not this year.  As I mentioned before it's inexpensive and easy to do, so why not.   Thanks again for the help!