Main Gear Lubrication

[aeromancfi]

I am missing the main gear trunnion grease fittings on the forward bearing ( fwd spar attach) for a 65E model. It appears that the fittings are broken off, or that the threaded stub is stuck, or that the opening for the fitting is stripped. How to repair or how to lube the bearing? I have tried using a conical point stinger on the grease gun to squirt some grease into the bearing, but to no avail.  Looks like opening is too small for an "easy out" extractor, and I am afraid of trying to drill out the hole, for fear of damaging the shaft. This is not likely a new problem, it's a poor design. Any fixes out there? One of the rear trunnion fittings is missing too,  but is easier to fix . I don't particularly want to have to disassemble the whole gear to repair a lousy fitting!

 

Thanks for the advice

 

Aeromancfi

[Guest]

The front grease fitting is pressed into the bearing, they get broken off when the grease gun end is wiggled side to side in an effort to pull it free. The portion in the bearing is only 1/8" in diameter.

The only way that I know to remove the old one is to remove the entire gear leg and then drive the broken piece through with a small pin punch and replace with a new one. The steel is quite tough, drilling results in a badly damaged hole.

The rear grease fitting is a threaded type, I believe it's 1/4-28 thread.

Clarence

[1964-M20E]

I believe those had a special very small male thread that screwed into the bearing.  Yes I have seen many without them for the reasons listed above.

 

I'd be generous with LPS2 and move on.  I have taken out the whole landing gear and it can be somewhat a PIA.  The retract spring tool is the key.  You then have to verify the gear rigging afterwards.

[cliffy]

The front ones I have seen are pressed in.  I used a 1/4 inch deep socket with extension to drive new ones in with a tap from a hammer. You may have a hard time finding them locally. Are you sure the old one is broken off in the hole? I haven't seen that yet. Always just pulled out completely. There are a couple of grease gum zerk nozzles that are adjustable for grip strength. Find one of those and set it up loose first and gradually tighten it down till it just seals to work correctly but not so tight as to be a PIA to get off the zerk.

[aeromancfi]

I appreciate the comments. As I said there is only what appears to be a stub ( does not extend beyond the bearing) with a tiny hole in the center, likely plugged up with dirt or old grease. I have seen some of the "push in" zerk fittings, but they have no threads, so I don't see how they could work except for friction on a interference fit. Seems the first load of grease would blow the fitting out.

 

So far the best advice (thank you) is to douse liberally with LPS, but that doesn't seem like a good long term solution. Also having once reset the torque values on the gear ( a painstaking process) I  am not interested in taking the gear out ( another lengthy process) best done by a Mooney shop. Any more suggestions?

 

aeroman

[Guest]

Alemite 3018 grease fitting is a 6-32 threas. Alemite 3019 is a press in grease fitting for 1/8" diameter hole. The exact part number can be found in the wing spar drawing of the IPC for your model, its not in the landing gear section because the bearing is riveted to the spar.

You might try something like the Alemite B 6783 needle adapter to grease the broken fitting.

Clarence

[aeromancfi]

Clarence: thanks for the Alemite info. I will follow up on that : both fittings and the grease adapter. How's that Mite treating you --L or C model? certainly not the same gear .

as the 20 series. 

 

aeromancfi

[Guest]

Clarence: thanks for the Alemite info. I will follow up on that : both fittings and the grease adapter. How's that Mite treating you --L or C model? certainly not the same gear .

as the 20 series. 

 

aeromancfi

The Mite is on hold at the moment, although there are a few other projects available at the moment. The RV4 needs my attention, annual and new canopy.

The genius of the Mooney gear system follows from the Mite to current models, the parts and operation are very similar.

Clarence