Oil leak MT Prop

[ellisr]

Hi, after the last flight noticed a few patches of engine oil on the left windscreen. Had the local workshop take a look and the attached videos show what they found around the Prop.

Note the plane just finished annual inspection a month ago.

Has anyone had experience with this and the required maintenance to fix?

http://youtu.be/WSxT1YZtJsk
http://youtu.be/SsdHW4SSq60

[youtube]http://youtu.be/WSxT1YZtJsk[/youtube]
[youtube]http://youtu.be/SsdHW4SSq60[/youtube]

Thanks in advance.

Russ

[ricksigler]

Hi Russ,

Rather than oil, it's probably grease from the hub. The oil is kept inside the governor by an O-Ring. The grease in the hub is forward of that and is usually what you find inside the spinner. How many hours on the prop? Mine started leaking grease at about 450 hours TTSN. To fix it, the prop must be overhauled. I did a completer DIY post here with photos about the prop overhaul process. FYI, the prop guy told me that the factory packed a lot of grease in the hub and that it will probably be okay for quite a while. You just have to clean the cowling and windscreen every time you fly. Also, if you clean all the grease out of the spinner it won't throw the grease onto the cowling and windscreen for a while, but I would plan on the overhaul soon. It's not a cheap process and takes quite a bit of time.

Rick

[rwtucker]

How many hours on the hub Russ?

Also, I'm curious. Does anyone know if the life of the O-ring is affected by your prop management behavior? Knowing that many of us have had problems with the hubs leaking, I change pitch verrrry slowly and only in the range of 2200 and 2700. I know that oil pressures change at various places in the CS system but I wonder if the pressures on the O-ring change much such that you can affect O-ring life?

[Antoine]

One way of minimizing this very annoying problem is to
- remove the spinner
- clean the inside of the spinner (this is where the grease lands first, after leaving the hub
- re-install
Buys you a few flight hours of peace.

MT fixed mine before overhaul by adding some sealant. It worked.

[rwtucker]

Added sealant where Antoine? Can it be done w/o an overhaul?

[Antoine]

Robert if I recall correctly it was around the area sealed by the O-ring.
This was definitely 1 year before overhaul.
MT removed the prop off and fixed it. Sorry I have no pic...

Best is to ask MT USA.

[ellisr]

Hi Rick

It's been about 356 hours (tach) since the last overhaul. The workshop was sure its oil, did you see the video I posted, is it possible confirm that visually from the vid?

Thanks, Russ

[ricksigler]

Russ,

I looked at the vids again. I still think it's probably grease. That's all the hub has in it unless the O-Ring leaks. At first, I thought mine was leaking oil because of the way it spattered on the cowl and windscreen, but it was grease. If it is oil, then you probably just need a new O-Ring (with the hours you have on the hub, you probably need a rebuild). Remove the prop and install the new O-Ring and put the prop back on. If you do most the work yourself it shouldn't cost much. Even a shop should be able to remove and install the prop in under two hours. I just did it to replace my alternator and belt. If is is oil, don't delay. The prop shop told me that if the oil leaks into the laminated blades, you have to replace the blades. $$$$$. Good luck.

[CFIDave]

For what it's worth, when we owned a DA40 we suffered (at different times) both an oil leak and a grease leak from our MT propeller hub.

They're easy to tell apart: You already know what used (black) engine oil looks like, but the grease leak deposited lots of tiny little YELLOW droplets all over the front of the cowling. Your videos definitely show an oil leak.

In both cases we immediately sent our MT prop off to a prop shop that somehow fixed the leak but didn't do a complete overhaul. Our DA40 at the time only had a few hundred hours on it.

[ellisr]

Thanks guys for the good info. Will keep you posted on the resolution. Russ