Oil in Belly

GAdams · #1 03-12-20, 08:37 PM

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 · #2 03-15-20, 04:46 PM

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 · #3 07-14-20, 07:58 PM

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 · #4 07-15-20, 08:57 AM

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

GAdams · #5 08-21-20, 11:06 AM

I finally got the old girl out of the shop. Doors close normally and stay closed. So Far...But not after some real gut wrenching trouble shooting. It took more than twenty gear cycles on jacks before the nose gear door would stay closed and some additional rigging of the nose gear door up actuator.

rrolland · #6 08-21-20, 07:51 PM

Glad you are making progress with that issue Gary.

OhioSkymaster · #7 03-17-21, 11:14 AM

So, did servicing the gear actuator/transmission seals fix the leak? I'm having the same issue of hydraulic fluid leaking from the belly. It's red, so no question of fluid type. After the last flight it leaked a puddle of fluid about 5 inches in diameter in just a few minutes after parking and shutting down, but after removing the interior and deck plates could not find any source of the leak. We're thinking of running the front engine and placing the gear lever in the Down position to pressurize the system and watch for leaks, before jacking and running the system with a mule.