Shear Pin for M816 Rear Winch

[Andy1234]

Today, I unspooled (and un-kinked) the cable on the rear winch of one of my M816's.

When I went to spool it back up, I was a little concerned when the winch drum did not turn!

Came to find that the shear pin was sheared, and I need a new one (the previous owner, Uncle Sugar, spooled the cable in too far, and bound up the cable and sheared the pin).

Currently making due w/ a 5/8" dia 4" long bolt, but I would like to have the correct thing.

Dia is 5/8", made of steel. Length is unknown (to me) as all I have is the center section. The pin is scored on each end. I can always take the pin out of the winch on my other wrecker, but asking here is a lot easier .

Anybody have an NSN or idea of where to find them? I did not see any info on it in the TM.

Thanks,

Andy

PS, greasing up 380' of 3/4" cable takes a LOT of grease!

 

[gimpyrobb]

I'll dig in the garage and see if I have one. What I got sounds like your description, just gotta find it.

 

[timntrucks]

yes that pin is a very large one.. big round head with notches cut into it.. i would hate to buy one but i would rather that than use the wrong pin. if i had more than one spare i would let you have it

 

[Josh]

From what I've read and some basicly calulations(which I think works). This is all assuming that the winch shear pin strength go up linearly with the weight the winch can handle.

I took the deuce winch max load and pressure the shear pin is suppose to shear., and multiplyed that by 4.5 (10k vs 45k) and a grade 2, 5/8in iron bolt is slightly weaker(about 5%) then what the normal shear pin. So you should be able to get away with one of these until the proper pin can be aquired.

That said, it really depends if the winch rating and shear pin strength scale linearly.

 

[zebedee]

yes that pin is a very large one.. big round head with notches cut into it.. i would hate to buy one but i would rather that than use the wrong pin. if i had more than one spare i would let you have it

Just got a couple from Memphis Equip.... $17 ea # 8330478

Did not come with a 'hairpin', 'R' pin or split pin to secure. (no biggie) Now I have to align the drive line to get the center plug of the old one out!

 

[raeme]

Good boy.
raeme.

 

[zebedee]

Just got done replacing shear pin, quite the fiddley job. So inlieu of a TM (yes I looked) here is my ZM - skinned knuclke tips:

1: Remove air supply to cable tensioner air cyl, slide hose through cross member. Gives access for swinging big hammer.
2: Use pipe wrench to rotate drive shaft (infront of the cross member) untill shear pin head, split pin end or hole in outer drive sleve is between 3 o'clock and 6 o'clock (clock face) looking forward.
3: If both ends are present, use cold chisel to pry/drive 'rivet' head end of old shear pin out of outer drive sleeve.
4: Observe through hole the alignment of center shaft relative to outer - looking for the center plug of the shear pin. Rotate drive shaft in either direction - one way may bind and actually drive winch. Use this function to rotate outer against inner untill alignment of holes is achieved, at 4:30 (clock face) or 45 deg. Best orientation for driving out...
5: Useing an 18" or so length of 1/2 rebar with one end smoothed off about 1" up the bar, have Sol B hold bar in outer shaft hole. Use large sledge hammer (mass needed as not room for good swing) to drive plug and other end out off shaft and back side sleeve hole. Mine took quite a lot of whacking. Even used a vernier calliper to measure the depth to see if I was making progress.
6: Slightly bevel end of new shear pin back to the far side of the split pin hole. This will help align the shaft and sleve holes when driven in if there is any deformity to the holes caused by the failure of the last pin.
7: Put a small drift or the re-bar through holes, move to 3 o'clock position - in line with cross member and realign with pipe wrench as step 4.
8: Mark edge of the head of the shear pin to show orientation of split pin hole.
9: Start shear pin into outer sleve with the split pin hole perpendicular to - NOT INLINE with the drive shaft.
10: Use decent sized hammer to drive shear pin to full depth. It helps if you are accurate but firm with hammer blows directly to shear pin head, avoid hitting winch worm drive casing or drive sprocket. Hemispherical head of shear pin makes useing a drift, even large one awkward and need extra hands. Drive head fully to shoulder out on sleve - otherwise split pin cannot be placed AND shear pin waist points won't line up with sleve/shaft points thus increasing effective strength of shear pin - will try to shear at full thickness not at designed points.
11: Apply new PTFE tape to air line fitting and reconnect air hose to cable tensioner actuator.