tips for flushing hydraulic system?

[zerobearing2]

Does anyone have any tips for flushing of the hydraulic flap/brake system? We discovered the hydraulic fluid has started turing to syrup; thinking its good idea to completely flush the system before replacing the fluid, but unsure of whats safe for the seals/o-rings...Any thoughts?

[Magnum]

Quote: zerobearing2

Does anyone have any tips for flushing of the hydraulic flap/brake system? We discovered the hydraulic fluid has started turing to syrup; thinking its good idea to completely flush the system before replacing the fluid, but unsure of whats safe for the seals/o-rings...Any thoughts?

[kerry]

You could consider flushing it with automatic transmission fluid.  I use ATF type F as brake fluid.  I've been told its the same specs as aviation brake fluid.  Just a thought.

[Shadrach]

Quote: kerry

You could consider flushing it with automatic transmission fluid.  I use ATF type F as brake fluid.  I've been told its the same specs as aviation brake fluid.  Just a thought.

[KSMooniac]

Buying the correct stuff isn't that expensive, so there is no reason to use ATF in my opinion.  I have a J with electric flaps and pumped the fluid up from my brake calipers using a pressure pot, after extracting the fluid from the master cylinder.  I suspect such a procedure would work for the pre-J models too, but am not sure.

[Kwixdraw]

5606 Is the legal stuff to use and it's still available. A way bad idea to use anything else unless you are really interested in ongoing issues with the FAA in the event of an"incident". Not to mention your insurance carrier will probably introduce you to the joys of subrogation and all the fun that is if they find out you put the other stuff in there.

[Kwixdraw]

If the system has been together, unserviced long enough for the fluid to be turning syrupy, you really want to take it apart and see what the internals look like anyway. If you have magnesium brake calipers you could be looking at some really nasty corrosion inside, just waiting to cause a brake failure at the worst possible time. Just went through this myself. Check the dates on your hoses too. I'd bet they need changing.

[jetdriven]

Check out the new standard hydraulic fluid,  MIL-H-83282. It is not nearly as flammable as it is a synthetic fluid It is purported to be compatible with all 5606 fluids.

Aeroshell 31 conforms to this standard, as does Royco 782. We are switching to it.

I did read a VAF forum that the conclusion was Mobil 1 synthetic ATF is virtually the same as the MIL-H-83282.

http://www.skygeek.com/royco-782-aircraft-hydraulic-fluid.html

[1964-M20E]

The pressure pot works well on mine the mechanic and I just start at the reservoir and bleed the flaps and or brakes as necessary.

[JaredDavis]

Check out the new standard hydraulic fluid,  MIL-H-83282. It is not nearly as flammable as it is a synthetic fluid It is purported to be compatible with all 5606 fluids.

Aeroshell 31 conforms to this standard, as does Royco 782. We are switching to it.

I did read a VAF forum that the conclusion was Mobil 1 synthetic ATF is virtually the same as the MIL-H-83282.

http://www.skygeek.com/royco-782-aircraft-hydraulic-fluid.html

 

 

Did you switch to 782?  Any issues?  I don't see how much fluid is required in the mm or ipc. 

[Mr Bill]

Aircraft Spruce has Phillips 66 X/C MIL-PRF-5606H hydraulic fluid for $6.85 a quart.

[orionflt]

stay away from ATF type fluids, depending on the additives it can cause problems with your seals. Mil-H-5606 is still widely available and if you want to upgrade to synthetic then use Mil-H-23282 you can mix the two without any issues,

 

Brian

[JaredDavis]

Hi,

 

Royco 782 is Mil-H-83282 as far as I know.  Anyone use it before? Jetdriven stated 2.5 years ago he was going to switch to 782.

 

Will 2 qts be enough?

 

http://en.wikipedia.org/wiki/Hydraulic_fluid

Common petroleum-based:

• Mil-H-5606: Mineral base, flammable, fairly low flashpoint, usable from −65 °F (−54 °C) to 275 °F (135 °C), red color
• Mil-H-83282: Synthetic hydrocarbon base, higher flashpoint, self-extinguishing, backward compatible to -5606, red color, rated to −40 °F (−40 °C) degrees.
• Mil-H-87257: A development of -83282 fluid to improve its low temperature viscosity.

[Hector]

Buying the correct stuff isn't that expensive, so there is no reason to use ATF in my opinion. I have a J with electric flaps and pumped the fluid up from my brake calipers using a pressure pot, after extracting the fluid from the master cylinder. I suspect such a procedure would work for the pre-J models too, but am not sure.

Yes, works exactly the same way on pre-J. I do it every annual using a garden sprayer purchased from Home Depot connected to the brake caliper with clear tubing.

Sent from my iPad using Tapatalk HD

[JaredDavis]

How much fluid is needed?

[Andy95W]

One quart of 5606 should be enough, but it'll be close.

As previously posted, suck out what's in the reservoir, push fresh fluid up from the caliper until it runs nice and red, repeat for the other caliper.

Suck out the reservoir again, and push fluid from back to front and up using the rear most fitting on the aft flap cylinder (just above and forward of the flaps themselves). When that runs red and clean, suck it out and refill the reservoir.

That'll change about 98% of the fluid. The last 2% will be in the forward flap cylinder (the pump) and it'll circulate through the system in about 2-3 flap cycles.

[N201MKTurbo]

I would never put ATF in my airplane, but I did top off the tranny in my truck with 5606. Worked fine and I never saw any ill effects.

[JaredDavis]

Anyone use Royco 782?

[Andy95W]

Is it MIL-SPEC 5606? If so, it's all basically the same and interchangeable as is.