force one prop hub seal leaking

[thepelican]

Gentlemen:

Question: Is the Force One bearing supported by the no. 4 journal only (pulley bearing journal)?

Or is it also supported by the case nose where the slinger ring normally resides? If it is unsupported by the nose of the case, is that where the new seal sits? I can find no drawings or descriptive specs of the hub on line anywhere.

No tech info but the limited info in the Great Plains prop ads.

Thanks up front.

 

[soneraifred]

The front of the case is welded up and machined so that the Force One is supported in both the #4 bearing area and where the slinger ring fits. The front seal is mounted in the front of the bearing. There are a few good photos of the assembly in the case in the Great Plains Assembly Manual.

 

[Map]

Here are a couple of pictures of the case and with Force 1 hub.

 

[Sonex]

Test flew today. same leak with new seals. Seemed to be more wear on hub where seals ride than hours would justify. I bought, didn't build this airplane. maybe hub from another engine. I guess a new hub might be only solution. I took a few thousandths off trying to smooth it out. I purchased a Great Plains assembly manual before beginning, mine says 50 to 60 ft/lbs to line up cotter pin hub and bolt holes. mine lined up at 50 so i pinned it there. hope thats enough. Couldnt find prop bolt torque anywhere, called A/P that sold his sonerai 2 years ago, he suggested 14 ft/lbs. A champ here at the airport with wood prop only shows 7 ft/lbs

I have the same problem. Changed the seals last year and still have oil leak. I suspect it is oil pressure in the case, so I will try the breather back to the carb, right now it is going to an oil separator, but even that has an outflow tube?

This GP engine supposedly had one hour on it when I purchased. Regarding the torque spec, I believe it depends upon the bolt thread. I read that there is about a 10 lb spread between fine and coarse thread.

By the way, I used the Harbor Freight hydraulic puller after reinforcing the hub. I maxed out the puller and no go until I tapped the hub with a mallet.

Thanks for all the suggestions, this has bothered me for years now.

 

[Marc W]

I thought my prop hub seals were leaking so I replaced them. It still leaked. I discovered it was leaking around the outside of the bearing.

 

[Sonex]

I thought my prop hub seals were leaking so I replaced them. It still leaked. I discovered it was leaking around the outside of the bearing.

How did you determine it was the bearing, and how did you resolve the bearing leak?

 

[Marc W]

When the new seals didn't stop the leak I cleaned everything up, flew it, and looked at it again. I split the case to reseal it.

 

[Sonex]

Ouch! Now that I think about it, that oil leak is not all that bad.

 

[Vigilant1]

Ouch! Now that I think about it, that oil leak is not all that bad.

Yeah, I think it hurts less if you save up a few squawks and then fix them all at once when they reach critical mass. The hybrid Aerovee/GPAS engine in my Sonex drips a bit from the front and I suspect the crankshaft fore-aft play may be at the limit, so maybe it's time to look inside.

Mark

 

[Sonex]

Yeah, I think it hurts less if you save up a few squawks and then fix them all at once when they reach critical mass. The hybrid Aerovee/GPAS engine in my Sonex drips a bit from the front and I suspect the crankshaft fore-aft play may be at the limit, so maybe it's time to look inside.

Mark

Any oil makes me crazy, but I can live with a few drops for now in my Xenos. So far it has not made it to the outside of the cowl except for back by the lower vent.

 

[Marc W]

Yes, the main seal was leaking badly too when I decided to split the case. It turned out that the steel shell of that seal was bent.

 

[thepelican]

Here are a couple of pictures of the case and with Force 1 hub.

Thank you for pics and remarks re; case nose function (support).

Do you know the Force One bearing size (diameter/ machined)? I am questioning the worthiness of my case, before I commit money.

Q #2: What is sentiment re; Super Vee hubs of old?

 

[Map]

The bearing OD is 2.300"

 

[thepelican]

Thank you Map!

 

[epijack]

Here are a couple of pictures of the case and with Force 1 hub.

Thanks for those pictures, MAP.
Do you have any idea how much flight time is on that engine? Reason I ask is that I THINK I see evidence of a great deal of fretting on the faces of the main bearing bulkheads where they mate to the other half, and from the second picture, I don't like the looks of any of the 4 lifters showing, especially the second from the left.

 

[Map]

About 250 h. Yes, it looks that way.

 

[epijack]

About 250 h

Thanks.