Fairchild 24 brake system complaint

[corn cob R4360]

Hi there, on behave of a foundation in the nertherlands I’m asking around if there are any people
operating fairchild 24's.

I have a 1939 model with original brakesytems, not long ago the brake sytem was replenished with aeroshell fluid 41 mil-prf-5606, and since that moment, I have the 2 cylinders jamming in their houses. It seems that the original brake cylinder rubber cubs been expanding due to the fluid 41, I was wondering if there is any info out there regarding this problem.

Greetings, Melvin

[Old Shep]

Melvin:

Your problem is that the seals n the cups swell up with the wrong fluid. If you used 5606 (red mil spec fluid for WW II US aircraft) and the brakes malfunctioned, you need to flush out the system and use automotive brake fluid (Dot 3 in the US, a clear fluid) instead. The cups will most likely need to be replaced. The expander tubes in the brakes themselves may or may not be ok.

Good luck. The local CAF unit here has a Fairchild 24 and it's brakes are acting up and I'm afraid someone used the wrong fluid.

Old Shep

[Obergrafeter]

The automotive Silicone based fluid should work and won't harm any parts. I think it is DOT 5, a little expensive but worth it if it don't hurt nuthin!

[Steven M. Dennis]

Melvin,

Both Old Shep and Ober are right on the money. The rubber seals will swell if they come in contact with MIL-H-5606 hydraulic fluid. Sounds like a seal replacement job is in order, unfortunately those seals are destroyed now as they are not at all compatible with the new 5606 fluid.

While you certainly could use Dot 3 as Old Shep mentioned, just be aware that Dot 3 has been known to be an excellent paint stripper, (don't get any on your painted gear legs surfaces), and will also hold moisture if introduced to the system.

I would try to find Dot 5 fluid as Ober suggested. It is a good performing brake fluid without any real drawbacks that I know of.

Hope this helps,

Steve

[Dave Hadfield]

The problem, as I understand it, is the rubber components in the Fairchild's expander tube brake system. They are not compatible with some fluids. They will swell up or partly dissolve.

And also some fluids can't be mixed.

Contact Mike Kelly of the Fairchild Club, is my advice.

Good discussion here: http://groups.yahoo.com/neo/groups/fair ... opics/5224

The previous owner put Dot 5 into the brakes on my F-24W. I haven't had to do a thing to the system in 300 hours flying other than inspect. (I use my brakes as little as possible -- just as a taxi aid, and almost never to slow down after landing.)

Dave

[corn cob R4360]

Melvin,

Both Old Shep and Ober are right on the money. The rubber seals will swell if they come in contact with MIL-H-5606 hydraulic fluid. Sounds like a seal replacement job is in order, unfortunately those seals are destroyed now as they are not at all compatible with the new 5606 fluid.

While you certainly could use Dot 3 as Old Shep mentioned, just be aware that Dot 3 has been known to be an excellent paint stripper, (don't get any on your painted gear legs surfaces), and will also hold moisture if introduced to the system.

I would try to find Dot 5 fluid as Ober suggested. It is a good performing brake fluid without any real drawbacks that I know of.

Hope this helps,

Steve

Thanks people for the feedback, as you can see in the pictures, stripping of paint already happened
The system was leaking so it was taken apart and cleaned up. When opportunity arises the system was replenished with the fluid 41. I guess being smart about this really took a turn for the worst, or let’s just call is stupid

I was hoping someone putted the cylinders back to gather in the wrong order, because it had jammed in its braking position, so it looked like a sloppy pedal, but finding out the cylinder had jammed in its maximum position, it really got me thinking to scrape a brake system pressure check in the ‘approach checklist’ however, I removed both cylinders and the rubber cubs are still okey, but I think they have swollen a little bit, but I don’t have a comparison to be sure.

Well, its hard to work in a foundation with problems like this, but as people over here like to say: ” can't or won't are buried in the cemetery”