3 Point LIft Arms Bent

[normde2001]

"Steel that bends & you heat & bend back - is much weaker than the first time. If it bent already, and now it's weaker yet."

It has always been my experience that if you heat a piece of steel cherry red, then quench it, it hardens the steel.

 

[jinman]

</font><font color="blue" class="small">( it hardens the steel.
)</font>

Norm, if you harden the steel, wouldn't it be more likely to break instead of bending? I'm not sure that's what you would want to have happen. ...or if it would happen. /forums/images/graemlins/confused.gif

I personally think that straightening the arms or replacing them with the new, stronger arms from NH would be the preferred method of repair. I guess what I'm saying is that you could have $200 worth of "grief" trying to fix a part that only costs $150 to replace.

 

[Slamfire]

If your dealer can't find the appropriate bulletin, find another dealer, yours isn't very good. If worse comes to worst, universal arms are available at places like TSC. They are straight though, so if your's are bent in some fashion they probably won't work.

 

[normde2001]

"if you harden the steel, wouldn't it be more likely to break instead of bending?"

Probably, but only after much more pressure applied. If too hard, next step would be to heat to straw color and allow to cool down slowly to temper, then test with a file.

 

[OkieG]

<font color="blue"> Generally I just lift the box and continue one, however this time when I tried to lift the I bent the lower right lift arm and I think the pin where the arm attaches.
</font>

The larger CUTs, like yours, have a lot of power, but it surprises me that the lift arm would bend from trying to lift. Sure sounds like a defective arm (or poor engineering, which I doubt) to me. You might try to straighten it by any of the means suggested in this thread, but I would be quick to strengthen the arm or replace it with a strong, new one.

I don't agree with the suggestion not to strengthen the arm for fear of breaking something else. Nothing should break or bend in the first place. Every link in the 3PH chain should hold up. The pressure relief valve will go into bypass mode before any component of proper strength fails. And if your bypass valve sticks closed (not likely), your hydraulic pump will fail (been there). You should be able to have unbendable lift arms and not have failure somewhere else in the system. Just my opinion.

OkieG

 

[Soundguy]

I agree with that.. the 3pt lift arms should be able to make the relief valve open.. etc.. On my NH 1920.. the lift is rated at over 1800#... lets you know what those arms are taking.. and that's not even into the safety factor..

I'd bend them, and weld a stiffener on and go.. its the cheapest fix.. Besides.. they will still be weaker than newer ones.. thus being hte weak link.. protecting the rest of the system anyway.

Soundguy

 

[jay_ch28]

I ended up ordering BOTH of the lower lift arm and the connecting pins. Even though only one was bent. I don't want to have to go through this again. I'm going to straighten out the bent arm and keep it for a spare, just in case.

Was what I did wrong? Lifting the box from under a root, ripping through the root. Anyone have any "best practices" they would like to pass on to a new guy for box blade use or finish mowing?

I've a got a 72" Befco finish mower and a 72" King Kutter Box blade, used on a TC40D. Thanks to all of you for all of your imput!!!

Thanks again,
Jay

 

[normde2001]

That's the way I do it; however, I must abmit, on a couple of occasions, instead of lifting the blade it caused the tractor to do a wheelie, causing me to have to jam in the clutch to drop the front end back down, but I also tend to run with scissors and stand on the top step of a step ladder.

 

[tawilson]

When it comes to lifting the arms, you're right, the relief valve will protect the tractor. However, the way I bent my arms wasn't with lifting, it was with my logging winch. I didn't see that one corner was against a small stump because of the snow, and that side took all the stress. My mistake and I don't know what would have happened if the arm hadn't bent. And I bent it back and have been using it with no problem. And I was repeating what a NH dealer told me. I don't know if it was NH policy or his opinion.

 

[OkieG]

<font color="blue"> the way I bent my arms wasn't with lifting </font>
The light materials bucket of my FEL has bent and twisted many times from using bucket forks. When that happens I just try my best to straighten it back out. No way do I plan on giving up the forks. However, the bucket obviously was not designed for use with forks. Anytime stresses outside of design parameters are encountered, damage can occur. Lifting a boxblade that's caught on a root should not have caused a problem.

<font color="blue"> I don't know if it was NH policy or his opinion. </font>
I don't know either, but probably it was his opinion. At my JD dealership I've noticed how little some salesmen know about what they are trying to sell. They'll say stuff off the top of their heads and make it sound like they know what they're talking about. As a tractor newby, I can still get sucked in, but limited experience and a skeptical nature around salespeople allows me to sniff out some of the crap (Oops, can I say that /forums/images/graemlins/confused.gif /forums/images/graemlins/blush.gif). One thing I know is that a 3PH doesn't have a shear pin to keep from bending lift arms. The pressure relief valve is the "shear pin" for any hydraulic tractor function, and should by-pass before damaging hardware.

OkieG