Glen Donnach

I have a 915A1, and 2 M871 trailers. I have a continual problem on both in getting them unhitched. I can pull the release lever out about 2 inches, see the mechanism move out but never enough to decouple. I eventually get it done by moving forward,backward numerous times and by magic it will eventually let go. Not sure why it decides to work or why it doesn't work smoothly every time.

Does anyone have the same problem or know what the issue might be?

Thanks,
Glen

doghead

Are you on level ground(side to side)?

Have you tried, after disconnecting airlines(setting trailer brakes), do you back into the trailer a bit?

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M818, M819, M35A2 w/w, M35A2, M109, M561 w/w, M274, M1008A1, M146, M105, M116A2, M101A2, Pioneer tool trailer, MEP-002, MEP-017A, 1990 Dodge Tug, 5ton winch shear pins


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Nonotagain

Sounds like you might need to pull the hitch plate apart, clean and lubricate it and re-install everything. Also make sure that the apron is greased because if they are dry and are a pain to pull out from under a trailer.

Second thing to check is that the trailer and tractor is level or atleast both on the same plain. When you crank the landing gear down the truck should ride up a good three or four inches from loaded height.

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1997 Pribbs M105a3 (X2)
1968 Johnson M105a2
1997 Pribbs M101a3
1997 Kasel M116a3
2005 Kasel M101a3 (X2)
1990 D&S M1061a2
1989 MEP-003a
1983 MEP-003a
1973 Kaiser M818

Glen Donnach

Thanks for the replies so quickly. I do usually try to backup a bit to ease the pressure. Hasn't worked the last couple of days. It is not a perfectly level spot, but not too bad. How much should I crank up the jackstands?
If nothing else works, I guess I can haul it to a paved parking lot. I live in the country so not much pavement in my neighborhood
Should I see light under the plate or is that too much lift

Thanks,
Glen

kc5mzd

If the trailer is empty and the truck does not have air suspension you should crank the landing gear down till it just touches the ground. If you start to lift the truck you might end up putting pressure on the pin and the locking mechanism.

M813A1

Just remember to lift the safety latch on the front of the fifth wheel plate as you pull the main release !! It will make it hard to un-hook if you do not lift the safety latch !! Try that it is far easier then removing the fifth wheel on play wih the latching mechanism

Scrounger

It sounds to me what you are having is a release problem. The fifth wheels on military tractors doesn’t usually get used enough to wear out. The problem you are experiencing sounds more like a lube problem. Besides lubing the top of the fifth wheel with grease the underside parts also need to be lubed. We use SPL100 to lube the stuff on our fifth wheels at work. Any lube like it will work. First you need to lube all of the pivot points where the linkage is under the front, and then lift the back up; a 2 foot long piece of metal or wood comes in handy, so you don’t get the grease on you. Then lube the underside from the back. If the grease in the jaws of the plate look like it is hardening up from lack of use spray some lite lube in there to free things up. After lubing the fifth wheel couple and uncouple from a trailer a couple of times to spread things around.
When dropping a trailer the landing gear should just touch the ground.

wreckerman893

If the trailer is loaded you need to crank the legs down to where they take pressure off the 5th wheel ( there is a LOW and HIGH gear for the landing gear)......if it is empty you can just lower it until the legs make good contact and slide right out from under it.

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kc5mzd

When I got my tractor I tried for a couple of days to get it unhooked without moving the saftey latch. Finaly I gave up read the TM and decided to go ahead and try lifting the saftey latch - It made it a lot easier...

Floridianson

Yea same here I have to take some pressure off the plate loaded or empty.

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James
1 Bobbed 5 ton with lockers in rear and W/W
30 Outher Military Trucks
4 Military Cranes
3 Military semitrailers
2 Military expandable semitrailers
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