Landing leg jack maintenance

[lfhoward]

Hi All,

The screw jack on my M116A3 trailer’s front landing leg has recently gotten harder to turn. I’m betting it needs some grease.

The technical manual says to remove the top plate and fill with grease.

What kind of grease works well for applications like this? Any tips on maintaining these?

Thanks!

 

[Coug]

grease type doesn't matter as much as just having grease in it.

Pretty much any decently thick grease that will stay in the gearing is good, such as any NLGI 2 grease.

 

[lfhoward]

Thanks Coug, I appreciate you answering so quickly. I have read somewhere that certain grease types are incompatible, but I don’t know what would happen if they were mixed. Is NLGI 2 grease what would have been used in it from its Service days?

 

[lfhoward]

Found it in my TM. NSN# 9150-01-197-7693. Grease, Automotive and Artillery M-10924-B (81349)

Now to figure out what this grease is called in civilian life.

 

[Coug]

yes, some are incompatible, and in a lot of jobs it does matter because of wear and pressure and what not.
Here we are talking about a set of gears that turns a couple dozen times under relatively light conditions, so it's a lot less critical.

below are the specs/features of that particular NSN

MRC	Parameter	Characteristics
AGAV	III End Item Identification	Mrap buffalo MK2A2; medium mine protected vehicle - mmpv
AKKF	Quantity Within Each Unit Package	14.000 ounces, avoirdupois
ARAR	Melting Point Temp Rating	180.0 deg celsius
CQJS	Minimum Dropping Point	220.0 deg celsius
CRWD	Effective Temp Range Rating	+25.0 to 1000.0 deg celsius
CSMB	Vapor Pressure Maximum Temp Rating	1000.0 deg celsius
FEAT	Special Features	Oxidation resistant, 5.5 percent lithium soap, dropping point at 0 degrees F:390 product name:marfak multipurpose 2, lithium hydroxysterate thickened; penetration, astm at 77 degree UNWORKED:295, penetration, astm at 77 degrees WORED:273, recommended for general automotive use where a single multipurpose grease is needed

. NSN 9150-01-197-7693. Mil-PRF-10924G. NATO G-403. Re-inspect 01/11.GAA is an advanced lithium-complex thickened, multi-purpose NLGI Grade 2 grease. This product is composed primarily of synthetic hydrocarbon base stocks, gelling agents, anti-oxidants and corrosion inhibiting additives. Designed to operate over the temperature range of -54ºC to 121ºC (-65ºF to 250ºF).is intended for use as a long-life, general-purpose lubricant and to provide surface corrosion protection of all ground vehicles and equipment. It is also an excellent lubricant for automotive and industrial applications where a wide temperature range or where infrequent re-greasing is preferred. This grease may be used in other applications where a NLGI Grade 2 grease with good oxidation and salt water corrosion resistance is desirable. GAA is also suitable for use in extremely cold environments such as cold rooms, cold storage lockers, ice plants, and on refrigeration or cold storage equipment. It will resist such environmental contact as humidity, ice, and road salts without hardening, washing off or deteriorating.

Basically it's a lithium base NLGI grade 2 grease, with some other stuff added to it for the military. There isn't any real reason why you would need any of the extra stuff just for the gears in the jack.

If you really want the military stuff looks like you can buy it here:
Grease 12C and 12D is tubes, 12A and 12B are can/bucket (bucket sold out)

Premium Genuine Issue U. S. Military Surplus. Including, United States Army, U.S. Navy and U.S.M.C. New Old Stock, Current Issue And Also Some Used.

We Sell Premium U.S. Military Surplus Goods

www.sprucemtsurplus.com

 

[lfhoward]

Awesome, thank you. The fact that it’s a lithium base NLGI grade 2 grease is enough info to find something compatible at the auto parts store.

 

[lfhoward]

Got some of this Lucas Red “N” Tacky grease that matches our specs.

This thread has good photos of the inner workings of the landing leg jack.
https://www.steelsoldiers.com/threads/m116a3-jack-leg-repair.194814/

By packing grease in the top, it’s easy to see how the gears get lubricated. But will the grease make its way to the threads on the main screw, and the square “nut” that moves the leg up and down? I suspect that’s where the friction is.

 

[Godspeed131]

Personally that’s my go to grease for mostly everything on the farm for work or play

 

[lfhoward]

It was a beautiful 65°F day so I decided to spend a couple hours doing trailer maintenance.

Today’s job: grease the tongue jack!

The jack had a few solidified clumps of former grease, but otherwise was completely devoid of lubrication. Probably the last time it was greased was at the factory or when it was in use by the military. I learned how to disassemble the unit and filled it with Lucas’ Red & Tacky. That grease is compatible with what was in there originally.

It works flawlessly now. Raising the trailer tongue up is incredibly easy now.

 

[fasttruck]

Lubrication is the key to successful operation. Many telescoping landing legs as used to fifth wheel trailers have zerk fittings to lubricate the bushing therein. GAA is the lubricating agent usually called for. What does your LO say ?