M929A1 bed hoist hydraulic rams and crosshead bent

[Buckwild]

Has anyone seen this before? I just bought the truck and the guy told me the bed lacked about 6" from going all the way back down after dumping,...it just wouldnt go down all the way. After looking at it for a while we finally noticed that you could see the ram shafts actually had a little arch to them, and the crosshead middle section appeared to be twisted and both of the pins on each side of the crosshead that actually pivot in the bed frame were bent. The guy said it wasnt like that the whole time he owned it, everything was fine until one day he noticed it wasnt going down all the way. Could he have overloaded it and not known it? I dont know much about these trucks, but I would think it would be hard to overload it, and the bed is in excellent shape, so its not like he was filling it with large boulders. He said he mainly moved dirt with it, and there are no highsides installed and doesnt look that there ever was, so it would seem hard to overload such a small bed with dirt. Is it possible for the hydraulic bed lock to not open and the rams still receive power? This is the only thing I could think of that may have caused this. Any input is appreciated! Also I'm new and this is my second post,,,so if it is in the wrong place I'm sorry, I thought it fit best here.

 

[162tcat]

Has anyone seen this before? I just bought the truck and the guy told me the bed lacked about 6" from going all the way back down after dumping,...it just wouldnt go down all the way. After looking at it for a while we finally noticed that you could see the ram shafts actually had a little arch to them, and the crosshead middle section appeared to be twisted and both of the pins on each side of the crosshead that actually pivot in the bed frame were bent. The guy said it wasnt like that the whole time he owned it, everything was fine until one day he noticed it wasnt going down all the way. Could he have overloaded it and not known it? I dont know much about these trucks, but I would think it would be hard to overload it, and the bed is in excellent shape, so its not like he was filling it with large boulders. He said he mainly moved dirt with it, and there are no highsides installed and doesnt look that there ever was, so it would seem hard to overload such a small bed with dirt. Is it possible for the hydraulic bed lock to not open and the rams still receive power? This is the only thing I could think of that may have caused this. Any input is appreciated! Also I'm new and this is my second post,,,so if it is in the wrong place I'm sorry, I thought it fit best here.

Pics?
My 817 bent the mount on the truck end when overloaded. Way overloaded, about 22k of broken up concrete slab stacked in the bed. It wasn't happy about dumping but did it little by little with some help backing up and hitting the brakes. Still works fine. I don't see how you would bend the cylinders. Mine doesn't have the bed lock so I can't comment on that.


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[country]

We have seen this happen quite a bit

The outer pins seem to be the weak point

the part looks like this

 

[Buckwild]

Thanks for the input! Here are some pics showing the damage. The pic of the side view of the rams is hard to tell they are bent, but they actually have a slight arch. This is what I initially noticed, and then got to looking at the crosshead, of course I have never seen one before, but it looked to me that the sides were bent, and the whole thing should be straight from pin to pin. The crosshead itself looks to be bent, not just the pins. Since this seems to be fairly common, is there a beefier fix? I actually saw a youtube video of a guy that that put a scissor lift in his, he said the factory one had a design flaw, but didnt say what happened. He may actually be on this forum, his youtube name is letsdig18. If its just a fluke, and wont happen again without abusing it then I have found a M817 that has been BEAT TO DEATH, but it runs and works and I can get it for a couple grand to steal the hoist parts, plus have a spare engine. Am I correct that the engine and bed hoist parts are interchangeable with my M929A1?
View attachment 755588View attachment 755589View attachment 755590View attachment 755591View attachment 755592

 

[porkysplace]

Thanks for the input! Here are some pics showing the damage. The pic of the side view of the rams is hard to tell they are bent, but they actually have a slight arch. This is what I initially noticed, and then got to looking at the crosshead, of course I have never seen one before, but it looked to me that the sides were bent, and the whole thing should be straight from pin to pin. The crosshead itself looks to be bent, not just the pins. Since this seems to be fairly common, is there a beefier fix? I actually saw a youtube video of a guy that that put a scissor lift in his, he said the factory one had a design flaw, but didnt say what happened. He may actually be on this forum, his youtube name is letsdig18. If its just a fluke, and wont happen again without abusing it then I have found a M817 that has been BEAT TO DEATH, but it runs and works and I can get it for a couple grand to steal the hoist parts, plus have a spare engine. Am I correct that the engine and bed hoist parts are interchangeable with my M929A1?
View attachment 755588View attachment 755589View attachment 755590View attachment 755591View attachment 755592

Your links don't work , this may help you post the pictures to the site.
[h=1]How to post pictures - a tutorial[/h]

 

[Buckwild]

Hmmm...thats exactly what I did. The pictures were actually there after I posted it too, now they are gone and just the nonworking links are there. Let me try this again...

 

[tobyS]

That looks like a fun repair!

 

[porkysplace]

Yeah , that looks like a fun project . I hate dual ram hoists.

 

[tobyS]

With about 2 cutting torches you may get enough heat in that crossbar to bend it back using wedges and plates tacked into place so it stays while you heat and pound in a taper. That is a lot to heat, but it looks like it MIGHT work if you can get it near read hot working one end at a time at first.

 

[porkysplace]

With about 2 cutting torches you may get enough heat in that crossbar to bend it back using wedges and plates tacked into place so it stays while you heat and pound in a taper. That is a lot to heat, but it looks like it MIGHT work if you can get it near read hot working one end at a time at first.

By the time you get enough heat on that to bend it back it's going to damage the rams .

 

[Ajax MD]

By the time you get enough heat on that to bend it back it's going to damage the rams .

Could he disconnect the rams and shore up the bed with pilings in the raised position?

 

[porkysplace]

Could he disconnect the rams and shore up the bed with pilings in the raised position?

After re-reading post #1 it looks like rams are bowed as well. To fix it right and make it dependable he needs to find some replacement parts .
Unless it's just a weekend toy , but if he counting using it on any site work you want reliable fixes .

 

[tobyS]

By the time you get enough heat on that to bend it back it's going to damage the rams .

No it won't. That mechanical joint won't put enough heat into the end of the rod shaft to matter. If the cylinder rods are bent, that is another story.

 

[Jbulach]

I would guess the M817 parts are interchangeable. Another option if the crosshead is symmetrical, flip it over, maybe spin the cylinder rods 180 as well. See if the bed will go all the way down and just run it...

 

[Buckwild]

I would guess the M817 parts are interchangeable. Another option if the crosshead is symmetrical, flip it over, maybe spin the cylinder rods 180 as well. See if the bed will go all the way down and just run it...

I kinda been chewin on this idea. Its already ruined, so its not like I can make it any worse I dont think. The crosshead does look like I can flip it, and who knows,..if i dont ever overload it it may work forever that way. I'm not gonna lie though,...having an excuse to buy that other M817 for parts is making my wallet burn

 

[M35A2-AZ]

I would take it off and find a shop with a BIG press and have them try to bend it back, then reinforce it. Safety note, be sure to hold the bed up with something.
On my M929 the bed will go almost 90 degrees up.

 

[tobyS]

The 817 and 929 I have both have fold up bed supports that hold at about 45 degree, just for this purpose.