Hydraulic leak - can't find the source

wslade2 · #1 09-02-23, 06:28 PM

I had a belly leak that was dripping from seam in belly skin. Similarly left a hydraulic stain about size dinner plate after a week. Floorboards up and hydraulic fluid all over from front to back by mains actuator.

After clean up and quite a bit of time (hard because the fluid weeps everywhere) finally found I had a drip from the emergency hand pump. At first didn’t suspect it because your brain goes to the worst case scenario, kept examining the main’s actuator.

I finally found via a good clean up and using a flexible scope (like from harbor freight, very affordable). I would see wetness in the well around the shaft. Suck it out with corner of paper towel. Wait a while, scope it and start seeing the fluid build up in the shaft well. The scope magnifies things making the tiny leak findable.

The pump was an easy rebuild. Just some o rings.

AV8ing · #2 09-03-23, 04:23 AM

Wslade2 - Actually, I started with the hand pump since I used to own a Cessna 210 and the only hydraulic fluid leak I ever had was from the hand pump.

I can say unequivocally that the hand pump is not leaking.

So will probably bite the bullet and pull the actuator next week.

Any tips on rebuilding the main actuator ?

wslade2 · #3 09-04-23, 08:38 AM

Then it probably is mains actuator. Give us tips and tricks for pulling that. I have had it in my mind to prophylactically pull and overhaul mine.

But two other things (I'm sure you looked at): Brake system also uses hydraulic fluid and has flexible lines at pilot left foot and near rear passengers hip that won't last forever, could crack and leak. These areas could flow into belly. You are D model, so "power pack" (more properly control pack since engine driven pump powers things) has a hydraulic fluid catch tray under it and drain tube runs loosely into belly. Be sure "power pack" not leaking.

Frank Benvin · #4 09-05-23, 03:39 PM

We rebuild the acuators and replaced all hoses . After flying it for a while I topped up reservoir and went flying Parked the plane and found a small bit of fluid dripping from the belly Looked for the leak everywhere and could not find anything We even put the plane up on jacks and cycled the gear to look for the leak. We figure that the reservoir was overfilled and leaked out the overflow while in the air getting sucked into the belly It has stopped leaking since.