3-point Hitch Backhoe Top Link Buckled: A Cautionary Tale

[oldpilgrim]

The worst part of the ride was my chest passing over the control levers well sorta over but mostly into my chest. Didn't puncture or break anything but I was very sore for quite a while.

 

[Mad Mac]

It turns out that our Mahindra 5555 is equipped with an hydraulic pressure lock-out valve. Intended for traveling with implements, when fully closed it prevents hydraulic fluid from reaching the 3-point hitch lift arms even if the position control lever is raised, essentially freezing them in place. Likewise, the draft control should be unable to cause the lift arms to move no matter what position it is in. This should solve our problem with the backhoe top link buckling.

The hydraulic pressure lock out valve is a knob located under the front of the seat. A blocking plate must be loosened and pivoted out of the way to allow the knob to be fully closed. Otherwise, it merely increases or decreases the speed of the lift arms to rise and fall.

Thank you one and all for your help.

 

[ovrszd]

Hmmmmm.... I think you are referring to the adjustment on most tractors with 3pt. Normally it's used to regulate rate of drop. I guess I've never tried it to regulate rate of lift. All three of my tractors have it. I'll have to experiment with that.

 

[Mad Mac]

Mahindra refers to the lock-out valve as the isolating valve.
Here is a link to another post on this forum that more fully describes it.
Isolating Valve

 

[California]

Once, while digging a septic tank hole, the top link on my 3pt hoe broke. My ride to the bottom of that hole, face first, was a thrill I won't have to do again. I have a frame mount hoe now.

The worst part of the ride was my chest passing over the control levers well sorta over but mostly into my chest. Didn't puncture or break anything but I was very sore for quite a while.

I have a 1980 model backhoe made in the US that was sold as OEM by both Yanmar and Kubota dealers. Its manual has an addendum for a recall kit, which is installed on my hoe. The kit adds restrainers below and forward of the three-point pins. The restrainers touch the lower edge of the 3-point arms and won't let the hoe fall forward if the top link should fail.

(This photo is a little confusing - the hoe is off, and parked. The tractor is parked next to it)

But this hoe still has a safety deficiency - there is no 'handlebar', loop, extending up over the control levers so falling forward would unavoidably push the levers. Also with nothing there, there is no way to pull yourself upward to get on the hoe. I added a barn-door handle (photo, similar) on top of the 'dashboard' to make a grip point there.

 

[oldpilgrim]

My son has it now. I made a much stronger custom, solid top link for it, but he still doesn't trust is so he has a chain wrapped around the seat post to somewhere on the tractor.

 

[DaveNJ]

Yeow! All the backhoes I've rented or borrowed were frame mounted except one, That one just felt weak and sloppy and convinced me that when I got a chance to finally buy one it would be frame mounted. [/I]

Once, while digging a septic tank hole, the top link on my 3pt hoe broke. My ride to the bottom of that hole, face first, was a thrill I won't have to do again. I have a frame mount hoe now.

 

[ovrszd]

California, those restrainers would definitely work if needed. Of course the failed top link would need repaired, but at least you wouldn't have to crawl up out of the hole to fix it!!!!

 

[California]

I found a better photo showing the safety restrainer (described in post #35) under the 3-point arms that will prevent the backhoe from pitching forward if the upper link breaks.



I took this photo for a different purpose initially, to show a weed, a little oak tree with more root than expected, that I pulled out using the backhoe from next to an orchard tree trunk. These (some are larger) were near impossible to dig out by hand right next to an orchard tree with their roots intertwined, now the backhoe pops them out like carrots.

This backhoe is a great toy.