Does your 3-point take a hydraulic beating

PineRidge · Aug 26, 2004

My last tractor had a feature that once the 3-point was lifted with an attached implement you could then throw a lever to lock the load in place. At that point you could relive the hydraulic pressure on the lift mechanism and safely travel with the implement in the raised position with no further strain to the hydraulics.

Unfortunately my New Holland doesen't have this transport feature and I'm sure there are also more than a few other makes that lack this lock as well. My point is this, when I'm not using my tractor I always lower any attached implement. But i'm sure driving down a bumpy road or pasture has got to put some serious pressure spikes to the hydraulic circuit. They could have just as easily been eliminated with a simple mechanical lock. Anyone else share this concern?

ZJ_HR · Aug 26, 2004

This feature I will never use. On bumpy road, if you have heavy implement, mechanical lach is too hard, and stress on tractor is big. Hydraulics usually have overloading valve to lower implement when pressure caused by sway is too big. This feature lower stress on tractor frame and 3pt lift.

MicroPilot · Aug 26, 2004

So you either stress the hydraulic system which PineRidge is concerned about, or you stress the mechanicals and frane which ZJ_HR would worry about. Can't win fer losin'.

My tractor has a knob that you can turn to close the 3PT valve to lock a load in the carry position. This valve also lets you regulate the speed the 3PT lowers. Is this the best of both systems, a lockout with hydraulic cushion?

I always thought that hydraulic oil didn't compress (or very little), and thats why it is used instead of air or water, so maybe it doesn't "cushion" the load.

KiotiJohn · Aug 26, 2004

My Kioti has the 3pt speed controller as well. Just close it completely and the load stays up regardless of where you have the 3pt hitch lever. I thought NH had these as well. Look under your seat somewhere just above the platform, maybe you have one too PineRidge. John

OkieG · Aug 27, 2004

My little JD has the knob under the seat. Like MicroPilot & KJ, mine adjusts the rate of fall, but when closed down, can lock the 3PH in place. Somehow, though, the relative inaccessibility of the knob makes it seem that maybe it's not intended to be used on a regular basis, ie as a transport lock for rear implements. Don't know for sure though. I dont' recall the Operator's Manual mentioning any use other than adjusting the rate of fall of the 3PH. I'll check and get back with you if I find anything interesting.

 driving down a bumpy road or pasture has got to put some serious pressure spikes to the hydraulic circuit 

Probably the same stress as driving with the FEL bucket loaded. No lock for the FEL.

OkieG

JerryG · Aug 27, 2004

The three point has a relief valve that comes into use when a heavy piece of equipment is being transported if something such as a large bump is hit. This protects the lift cylinder and valving. If the rate of drop knob is turned off the relief is also turned off. That is the way, the rate valves are made. The chance of damaging the lift cylinder and valving is greatly increased because of the stress placed on the components from the shock load. Don't turn the valve off during transport.

KiotiJohn · Aug 27, 2004

Kioti Owner's Manual under section, "Using 3pt Hitch":
When transporting on the road, set the implement lowering control in the "LOCK" position to hold the implement in the raised position. John

JerryG · Aug 27, 2004

Either Kioti is different from the rest of the world or they are referencing to the position lock for the position control lever.

txdon · Aug 27, 2004

"Anyone else share this concern?"


The Kubota Grand L series tractors, 3130-5030, have a 3-point hitch lowering speed knob located in front of and below the seat. It has three positions: right is fast, up is slow and left is lock.

The manual states: "When transporting on the road set the implement lowering speed knob in the "LOCK" position to hold the implement in the raised position."

The manual also cautions: "To avoid personal injury: Fast lowering speed may cause damage or injury. Lowering speeds of implements should be adjusted to two or more seconds."

RoyJackson · Aug 27, 2004

Per the John Deere manual for the 790:

"The speed-of-drop/lock valve is used with rockshaft control lever. This valve will control how fast a three-point hitch mounted piece of equipment will drop. This valve will also hydraulically lock the rockshaft (three-point hitch) in a desired position ."

So, it appears Deere expects that knob to lock implements as well as rate of drop.
I didn't know this, so I learned something today...

KiotiJohn · Aug 27, 2004

( Either Kioti is different from the rest of the world or they are referencing to the position lock for the position control lever )
Well, I don't think it's Kioti that's different than the rest of the world Jerry. The certainly mean the 3pt drop speed control and even have a picture accompanying the text.
As you can see from the other posts, it's not just Kioti. John

MicroPilot · Aug 27, 2004

( Kioti Owner's Manual under section, "Using 3pt Hitch":
When transporting on the road, set the implement lowering control in the "LOCK" position to hold the implement in the raised position. John )

I don't have my manual in front of me to quote from, but it says essentially the same thing as KJ's.

PineRidge · Aug 27, 2004

My tractor has a knob that you can turn to close the 3PT valve to lock a load in the carry position. This valve also lets you regulate the speed the 3PT lowers. 

Naturally my New Holland is equipped with this feature as well but my thoughts are that if the valve is completely shut off with a heavy implement suspended in the air then the shock loads within the lift cylinders may be more prone to damage internal parts. I think the chances of that happening with a mechanical lock were minimized compared to the present set-up. What do you all think? /forums/images/graemlins/frown.gif

Food for thought.....

mwood · Aug 27, 2004

Are we absolutely sure that this shutoff cannot be bypassed if the check valve were to be activated? The most logical situation would be that this shutoff would hold the implement unless there was sufficient stress on the 3pt hitch. If the pressure on the cylinder exceeded the maximum rating, it would trip the check valve and the implement would drop a little.

Just want to be sure we completly understand the system here (and I'm curious too! /forums/images/graemlins/laugh.gif)

Golfgar4 · Aug 27, 2004

( What do you all think? )

Maybe a quick telephonic communication exchange with the dealer would be useful? /forums/images/graemlins/wink.gif

WVBill · Aug 27, 2004

Maybe the mechanical lock was there so you could raise an implement and lock it in place, shut down the tractor and work on the implement without worrying about leak-down.

slowrev · Aug 27, 2004

I have adjustable chain drop limiters on my tractor. Works great, supports my 3/4 ton counter weight well and I can set how low I want the front of my cutter to drop and not worry about it.
The chains hook to the top pin ends on the tractor rear and on the lift arms.

KiotiJohn · Aug 27, 2004

( I think the chances of that happening with a mechanical lock were minimized compared to the present set-up. What do you all think? )
I agree that a mechanical lock would be a good thing, but I don't think that turning off the drop control lets any pressure be applied to the cylinders. Once it is shut off, the position control would be moved into it's lowest position and I think the fluid is diverted back to the reservoir. Not sure of this, but looking at mine it seems that's what happens.
I'll try to get a response from a Kioti engineer on the mechanism of this. John

beenthere · Aug 27, 2004

I think I'd rather have the load from the 'bumps' on the hyd. oil system rather than on a mechanical lock mechanism. It would take a pretty healthy lock mechanism to hold that load mechanically.
At least, in all my years of 3pt systems (50+), never have felt a need to hold a 3pt load up with anything other than the hydraulics. /forums/images/graemlins/wink.gif

Steve_Miller · Aug 27, 2004

Here's my two cents worth. I don't think any manufacturer would allow the relief of the 3ph to be blocked in any manner. This could deadly to any 'o' rings, seals, shafts or whatever if overstressed by our abuse intended or not. First off if the load is too great for the 3ph, it will bypass and not lift the load. I'm sure we've all tried to lift something bigger than our tractors were capable of at some time or another. (I know I have) The bypass has to be in the circuit to protect. If not a bouncing 3ph backhoe (first thing I could think of) could in theory break the tractor in half, or as in a previous post (winch troubles) tear the top link housing clean off or rip bolts out. If the load becomes greater than the relief can handle 'I' think it will drop some distance, whatever that may be.

Steve