Backhoe Mahindra 3720 backhoe for the 3016

[kneedeep]

QUOTE=DavesTractor;3142689]When you extend the bucket ram all the way, it is at it's weakest point. Hydraulically extending or retracting the bucket only at that point will not bend the ram, as the pressure relief prevents that from happening. But if you leave the bucket ram well extended and then put a bunch of additional force on that ram with the boom cylinder, that can bend or break a ram. You see, on most compact backhoes, there is no way for the oil in the bucket ram to relieve itself when the spool for that cylinder is closed. There are ways to plumb in a load relief (wrong term I think) that will let the bucket hydraulically uncurl, but typically smaller backhoes do not have them. I've bent a bucket ram or two on 10k lb mini-excavators digging out stumps before I figured out what was happening. If you understand the dynamics, which took me a while, you tend to not bend the bucket rams.[/QUOTE]

Are you talking about curling the bucket in, which extends the cylinder out and pulling up with the boom? I can see how that move would bend or break the cylinder as the ram is at a weak point.
The pic of my unit on a pallet has the curled and the cylinder completly extended.

 

[DavesTractor]

Are you talking about curling the bucket in, which extends the cylinder out and pulling up with the boom? I can see how that move would bend or break the cylinder as the ram is at a weak point.
The pic of my unit on a pallet has the curled and the cylinder completly extended.

View attachment 307522

Yes, that is the idea. By the way, it is possible to put a relief in the system between the cylinder and the main valve that dumps the excess pressure to tank in situations like this. It eliminates the possibility of this sort of breakage, but it really isn't needed. We retail dozens of backhoes a year and we see less than one of these bent rams a year....and the cause is predictable. Now if I were to put a 3720 into a rental fleet, I'd put a relief on it.

 

[bindian]

Are you talking about curling the bucket in, which extends the cylinder out and pulling up with the boom? I can see how that move would bend or break the cylinder as the ram is at a weak point.
The pic of my unit on a pallet has the curled and the cylinder completly extended.

View attachment 307522

Kneedeep,
I think you won't have to worry about that with your 509. Over 700 hours on my 511, if something was going to break or bend.... I would have done it already. All I have had was a leaking swing cylinder, which Mahindra has a complete rebuild kit for.
hugs, Brandi

 

[perryg114]

I know this is an old thread but what are the specs for the 3720 backhoe? I know the curl and dipper forces changes every time the number do. Bought a used 3016 and might put a backhoe on it at some point.