Winch Shear Pins

[doghead]

I have been using winch shear pins that i bought from Saturn Surplus. I seem to shear them pretty easily. My question is, should I be able to winch the truck forward if the object I am hooked to does not move with the brakes depressed to the point that all wheels skid? (level sandy ground ,engine 800 rpm) When I first got the truck, it had a grade 5 bolt in it. I was able to shear that and a few more when i had not read the tech manual and chained the truck to a large tree and tried to winch something very heavy and the truck was facing a 30 foot drop-off. When I realized that it uses an aluminum pin, I promptly ordered some and have been using them. I can tell you that when the bolts sheared, there was a light "snap" noticed. With the aluminum pins, I feel nothing. The only indication of it shearing is the fact that nothing is moving. I really would like to think that the winch is capable of "dead dragging" the deuce with all wheels locked. For me this has not been the case. I do realize there are capacity increasing options such as doubling with a pulley and less cable on the spool. In any case I just want to know if you guys have had better success than me when it comes to Heavy winching with your trucks. Is everyone here using the aluminum shear pins?

 

[Stretch44875]

I haven't broke my aluminum pin yet. Only done some light winching thou. Pulled a cherokee out of the mud, it was to the frame.

Dennis

 

[WillWagner]

Funny thing, I was trying to winch out a bottle brush stump for my neighbor yesterday. 1st time I have put aload on the winch. Had it in low, slowly let the clutch out to take up the slack, stump started to move and the front of the truck kind of squated. pushed the clutch in and the cable slacked up, started to re engage the winch, nuthin, sheard the pin. Had the e-brake on, the truck didn't try to move...the front wheels were against a curb though. Would have thought the shear pin was a tad more robust! Have used winches b4..maybe it's the torque?

 

[rdixiemiller]

I read in one of the 1950's tech manuals that the steel pins had been replaced with aluminum to prevent damage to the frame or driveline.
I have seen wrecker frames twisted all over the place when people winched off to the side with the truck up against a tree.
The winches were designed to help recover a stuck truck, probably a 15000# pull was all they were rated for. Now, the winch is capable of much more, but you can wreck a truck frame in a hurry if you are not extremely careful, and knowledgeable of winch operation.
Think about it, these were designed to be driven by draftees.........

 

[ktm380]

My truck had all-thread for the pin when I got it. So I replaced it with a new pin bought from ebay (aluminum pin). Well the pin broke the first time, I was moving my 83' Bronco on level ground in neutral and e-brake off. Is it possible that there are a bad batch of these running around?

 

[DDoyle]

Sounds like the winch and shear pins are working properly in the first instance. The winch is rated at 10,000 lbs. The M35A2 weighs more than that - without the coefficient of friction that would come with the "brakes locked" scenario.

I've gone through perhaps a half-dozen shear pins - all surplus, in various situations. The biggest strain, which did not shear the pin, was winching a tank from a ditich - the transmission housing flexed enough that gear oil leaked between it and the PTO (fortunately, it didn't break). I bought a truck once that had the shear pin replaced with a bolt - and it had a burst winch housing...and I've seen several burst transmission housings.

Best wishes,
David Doyle

 

[Djfreema]

I dont have any extra pins but was thinking of buying a 3 foot section of aluminuim rod and cutting it down to the right size for use as extra pins. Is there anything special about the aluminum used to make the pins?

 

[williamh]

it took me all of 5min. of playing with mine to shear the alum .pin off ... took 20 min to shear off the first bolt ...took another 15min. to bend the crap out of the top guard/bracket and ruin the cable ... still have the bolt .. have pulled down trees and pulled out other trucks and had lots of other " experences " with it .. the alum. pin was too weak and a grade 5 bolt is too strong ...

 

[DDoyle]

DJ,
Yes, there is something "special" about the aluminum. As you probably know, aluminum (and other metals) come in a variety of alloys - and for the pin to work as engineered, the pin is to be made of a specific alloy.

Best,
David

 

[ktm380]

So what do thing of some cheap Harbor Freight bolts? Maybe that would be right between the aluminum pin and the grade 5.

 

[Towman2277]

This is what I discovered.....the aluminum pins work great, and shear as they were designed....to keep a complete fool from tearing the truck apart. BUT, i'm constantly winching HEAVY pulls, so the aluminum shear pin will not work for me, as I bury my truck DEEP in the mud pits, and i'm always pulling stuck back-hoes, various machinery, etc. What I have come to grasps with is, I use a grade 8 bolt that WILL NOT shear, and i'm very careful. I only do straight pulls from the truck forward (no side pulls), and I ALWAYS have a spotter at the front watching and letting me know whats going on- ( in a safe place though). I would recommend staying with the aluminum if your new to winches and the theory of recovery is mind-boggling, to keep from hurting yourself and your truck. If you have a watchful eye and understand resistance and recovery weakness and strenghths, then you can drop in a quality bolt and go pulling. And yes....I can drag my truck with wheels locked....until I run out of cable!!

 

[JohnnyGTO]

What about using snatch blocks to offset the weakness of the aluminum pin? It takes more time to setup but there is an advantage just ask Mike on Dirty Jobs!

 

[Recovry4x4]

Perhaps you guys are using the wrong grade shear pins. I bought a stash of genuine GI pins from Gene Patano in CO. I can drag my truck with locked brakes easily with the correct aluminum shear pin. If the holes in the shaft or yoke are wallowed out, it will shear the pin as well. I have loaded it to the point of beaking them too so they are the fusible link. The ones Memphis sells I don't think are right. The GI ones don't have a head and require a cotter pin at each end. I once again refer everyone to FM 20-22 (in the tm section) for a good read on everything recovery. With the proper calculations and use of snatch blocks, you will never break that shear pin.

 

[Stretch44875]

My pins came from saturn surplus, they have the cotter pin holes. Just remembered I did try to winch a big chunk of concrete out of the ground once. Squatted the truck pretty good, and broke the small chain I was using. Pin was okay.

Dennis

 

[Recovry4x4]

Another thought for those breaking pins, are you guys using low gear of the PTO?

 

[mcinfantry]

i pulled a 36000lb cherry picker mired PAST the outriggers and over the lower edge of the rims (up to the axles) with 3 snatch blocks and a grade 5

i TRIED to pull a k3500 lineman truck out after katrina with an aluminum pin, broke in 1 sec

i TRIED to pull me out of a hole with an aluminum pin and it sheared in one sec (i had to use 3 grade 5's!!!!!!)

i pulled me, and that office trailer out single line pull with a grade 5.

all pulls in low

 

[doghead]

Kenny, yes pto in low speed, the Saturn pins do have 2 cotter pins. I am guessing they are not made of mil spec alloy. I will give Jay a call today and ask what he knows. Kenny, your response " I can drag my truck with locked brakes easily with the correct aluminum shear pin. " confirms that it can with an aluminum pin. I am now in search of the correct mil spec pin. Thanks to all for your input! Eric

 

[ARMYMAN30YearsPlus]

I have not broken the pin but while I was in Iraq my son used the duece to try and pull out a 20 foot evergreen tree. He broke the pin and it stayed that way till I got home, ( my dad would have expected me to fix this) I found out he was straight line pulling it thinking that the winch was a super duper capacity since his TJ had a 9K that would pull him out of skid plate deep mud. He wound up pulling the tree out by hooking to the rear and driving in low 1st gear. I have two very heavy duty snatch blocks that would have saved the pin but his over estimation of the 10K rating brought this about. I watched in horror when a stuck M816 tried against my advise to winch themselves out of the swamps along Virginia Rt 17. They had pulled over to recover a duece with a leaking return line. Since the duece was right on the edge of the swampy ground I told them to start the duece up and get a better hooking angle. They said we can get it and promptly backed the wrecker up to the duece and sunk rear end into the swamp. I told them let me start the duece and pull you out they said we have this under control and then ran the rear winch line to a tree across the road with a fleet angle of about 85 degrees. I was fuming but since back then I was a second lieutenant they told me to shut up.

When they started winching the line tightend and with a pop the tree across the road was pulled up from the roots and headed for the power lines parallel to the road. As the power lines arced a sprayed sparks all I could think of was the lines coming down on the winch line and having two dead Soldiers, I told them WATCH OUT and they jumped off the wrecker. Shaking I told them I would take care of things.

I started the duece with the disticnt oder of diesel fuel and drove around to the front of the wrecker hooked it up and dragged it out. By then the situation had calmed and the power lines did not come down. They cleaned up the tree and the wrecker came around and hooked up and towed it to AP Hill.

From that point on in my Army life I vowed never to let stupid things happen if I could stop them.

That long story was just to show that if you use the winch correctly the pin should only break when the 10K capacity is exceeded by improper fleet angle or failure to use snatch blocks to do the winching.

 

[doghead]

From that point on in my Army life I vowed never to let stupid things happen if I could stop them. You must be a very busy man!

 

[mangus580]

I have winched several hundred apple trees over with my deuce (plus many other kinds of trees, and of course I winched the deuce out of my back yard )

I use the pins from Memphis, and they work great. I can drag my truck anywhere with all 10 tires sliding with my winch. No issue at all.

When I first got the truck, I have no clue what it had for a shear pin. I just know, it broke the first time we used the winch. I had a buddy make a few pins out of 6061 Aluminum, and the sheared almost with no load at all on the winch!

I can also tell you, that even with the Memphis shear pins, I was able to trash the upper and rear plate on the winch. I have even mangled one of my front clevis's (winch kicked in gear unexpectedly) before the pin sheared. Talk about a sickening sound, when you are too far away to do anything about it! I thought the engine was coming apart. Was bogging way down, and all sorts of metallic grinding and popping.... right up until that pin popped...

I think my heaviest winching, was pulling an Allis Chalmers HD11 out of the mud. It took 3 snatch blocks, and a big huge tree to do it. I dont think I have ever heard the turbo scream that much since.