Oil in Belly

[DrDave]

Okay, let me add one more thing. I promise this won't be wacky like the copper line mistake. We developed a small collection of oil in the center bay of the floor under the gear actuator. The oil would also drip off the left gear leg door if it was left open. I put towels under the motor for a couple of days. After two days the towel under the sump quick drain was wet. The oil was running off the sump drain and down the inside of the lower cowling into the belly.

I tried to attach a picture. Hope it works.

Dave

[GAdams]

Here is a picture. It's not oil, it's not 5606, it's not fuel. My mechanic's theory on the hydraulic fluid disappearing after the power back overhaul was, air bubbles were stuck in the system and as the gear was cycled the hydraulic fluid needed filling. The hydraulic level has stabilized an I have not added hydraulic fluid in quite awhile. He may be right. I don't know. I appreciate all the input. Please keep it coming.

[JAG]

Based on the picture - it sure looks like engine oil...if not pin hole in pressure line, then it is breathing out of front engine or leaking like Dr. Dave's issue.

Is it sticky? I have seen old contaminated 5606 (Hydraulic fluid) take on a yellow color before...very rare but it can happen. OR - Did someone put a different fluid in your brakes?

I have personally just purged my brake system after resealing my brakes and installing new flex lines. I have one of those brake bleeding pressure pots from ATS, and I took a polyFlo fitting and screwed it (pipe thread) into vent hole on the top of the master cylinder. Off the polyflo fitting I attached a length of polyflo tubing into a container, and just pushed fluid up from the brake bleeder through the system with the ATS pressure pot. This flushes the whole brake line from the bleeder to the master cylinder. Once the fluid ran clean and fresh, close it all up and your system is clean, filled and bled all in one shot.

The area you have the fluid is coincidentally where the swivel fitting is for the brake lines.

Let us know...

Jeff

[GAdams]

It is not sticky but is a heavier weight feel to it than the oil I use in the engine. But I do recall seeing the same fluid running from the right side of the front engine several months ago. I'll check the fluid color in the breaks as well.

[wslade2]

just as an experiment, I took some brand new red 5606 hydraulic fluid and put it on a dirty old paint can lid. Next morning it wasn't red. (I don't know why: because it spread out, dye evaporates, fluid evaporates or what.) Looked a lot like your picture.

Drying hydraulic fluid evaporates and thickens. More copious old hydraulic fluid very thick approaching gummy.

Your picture also looks a lot like what it looked like around my leaking emergency hand pump. I looked for a hydraulic leak and not an oil leak because that was what was most likely for the circumstances. I found a hydraulic leak and it stopped the problem.

5606 Hydraulic fluid is in the brakes as well as landing gear system.

[GAdams]

I'm still trouble shooting the oil in the belly. We have discovered it is coming from the transmission that houses the worm gear which actually cranks the wheels up and down. Does anyone have a better name for this device? The hydraulic engine pump drives the worm gear based upon gear handle selection. When I select up it leaks when I select down it doesn't. I was trouble shooting why all the gear doors would not stay closed with the gear up. It turns out they will when the aircraft is on jacks and operated by a hydraulic mule. But when the engine pump is put on line and the fluid gets low in the reservoir the gear doors will not stay up. I'm talking a half pint low and bubbles are in the system. It seems when the seals leak on the transmission it draws in air when it is not under hydraulic pressure. Air being sucked into the transmission creates the bubbles and while it looks like you have sufficient fluid on the site glass it did not. Bubbles are bad for the system to work properly. The yellow fluid I was reporting is in fact older hydraulic and maybe it turns yellow because of the cavitation the system is experiencing. To get that transmission out is 2 days of work. The local mechanic won't open it up to replace the seals and wipes so off to the overhaul guy. $1700. Plus days and days of labor troubleshooting and R&R. Hopefully the gear doors will stay closed. Don't know.

[JAG]

Thanks for the follow-up on this issue - sure is nice to have some closure when people discover something like this. That main gear actuator (aka transmission) is a bugger to get out - but looks like you have solved the issue. Thanks again for sharing.
Jeff