Three point hitch hydraulics on L3400

[BastropMetal]

Hello, I am a new tractor owner and new to the forum, so I might have some basic questions, please be patient.
About 8 months ago I bought my first tractor, an L3400 with just under 800 hours on it. The main project I needed it for at first was to help move a bunch of road base to build a road through a muddy area on my property.

When I first started I had a little bit of frustration using the box blade. It seemed the box blade would not stay at a set height. If it contacted the ground and "dug in" it would pull itself even lower into the ground. I could pull up on the handle and the box blade would pop back up, but I coudlnt ever figure out how to keep the blade at a fixed height.

Recently I got 3 point hitch mounted auger for digging some post holes. Whereas before with the box blade I wasnt sure if I had an issue or if it was operator error or my poor understanding of how the hitch was supposed to operate, using the auger has me pretty convinced that the hydraulics on the 3 point hitch are not working right.

I engage the pto, the auger starts spinning and then I lower it to the ground. The auger instructions specify clearly that its important to maintain depth control and not push it too far down. This is impossible. As soon as the auger starts removing any amount of material the 3 point hitch lowers and the auger starts to screw itself into the ground. I pull back up on the hitch and the auger pops up, bouncing around wildly.

I dont have experience with hydraulics but I think have I have a decent understanding of the theory behind the operation and I strongly suspect that I'm either getting leak by the seals on the cylinder or some sort of failure in the valve.

I searched the forums and saw some posts saying that a 3-point hitch that bounces around a bunch could be the result of the position control rod needing adjustment. I see that part mentioned in a diagram the workshop manual but I dont see much in there regarding troubleshooting or adjusting it. Any advice there would be greatly appreciated.

I'm posting here for a three reasons:

1. Sanity check in case there is something obvious I'm missing that i should check first before attempting a hydraulic repair
2. Any suggestions on tests I can run on the tractor before I start that would be helpful in diagnosing which possible item needs to be replaced / repaired
3. Tips for a novice on how to do whatever repair it is eventually determined that I need.

Thanks in advance for any help you can provide!

 

[Captain13]

You could put the box blade on, raise the 3 pt all the way, measure the lifting arm height, shut off the tractor and wait a while. Go back and measure the lifting arms to see if the hydraulics are leaking down. If they are, then you will have to go from there to troubleshoot.

i just did the control rod adjustment on my M7040 last week. It’s a lot easier if you have the workshop manual instructions. I have draft contro on my tractor so I started from scratch and di the draft control rod then the 3 pt hitch rod. Everything works correctly now.

Look in the workshop manual for 3 point hitch control adjustment and if you have draft control, look at the section following that on draft control adjustment. You have to load the three point hitch with about 100lbs to do the adjustments.

If you raise the 3 pay all the way with the tractor running and you hear the pressure relief valve activate, you definitely need to adjust the 3 pt control rod.

 

[Russell King]

To provide some basic clarification about the 3 point hitch operation since you asked.

The three point hitch on most tractors is cap of lifting loads only. There is no downforce from the hydraulic piston in the three point hitch.

The position control lever will hold any implement at a certain position in relation to where the lever is positioned. For most implements they start out touching the ground and then can be positioned anywhere between that position and the maximum lift position. Some implements can remove surface (blades) dirt or turn the surface over (plows) or dig holes (augers). Since these have been designed to be below the surface where the tractor tires ride the three point hitch is designed to allow the implements to move down and be held at different points below the surface. Often there are complaints about the hitch not moving up until the lever is moved to higher numbers. But it is correctly operating per design.

in particular the auger will try to pull itself down and if the position control lever is in the fully down position and could screw itself into soft soil. The tractor may not be able to lift it up and there is normally no way to turn it in reverse except manually. So the position control lever needs to be adjusted up to allow the auger to move the dirt upward and out of the hole or be lifted out.

On the box blade and getting the surface flat it takes some effort to do that by adjusting the position lever up and down to gather or shed material.

I think that you tube videos are available for operation on most implements but it will take some time to get proficient with them.

 

[number two]

Jerky 3-point hitch on standard L tractors has been discussed at length on Tractor-By-Net forum.
May want to check it out!
Good Luck!
Welcome!

 

[old and tired]

First, is the tractor manual tranny or HST? (mainly needed for serial numbers in the next question!!)

Do you know the year it was produced? 2004 to early 2006... HAD "JERKY" 3ph. If you don't know the year; What serial number tractor do you have? (first 3 numbers is all you need to post)

Well crap, Messick has changed the parts "lookup" and it removed serial numbers - I could boot up my old computer and find serial number split but if you are before (roughly) SN# 57,000-ish you bought the older and jerky version of the 3 point hitch. It does depend on your transmission.

IT SUCKS... but it does lift and "works" but not like any other tractor.

Get back with us and we might give you things to try...

 

[Jim L.]

Bastrop

I can offer my own experience digging post holes with an L3800. Soil here is cohesive clay. One thing to note is that the 3-point attachments are on a chord determined by the arc of the hitch. Ideally the tractor should be parked so that the auger shaft is plumb when the auger is close to being bottomed. In other words, you want to be able to lift the auger out without touching the hole walls and adding resistance to upward motion.

Another observation is that the cohesive clay will overcome whatever 3-point lift the tractor might muster. When augering, I periodically lift the auger up the hole to spread spoil from out of the hole. At the bottom stage, the moment that I feel the auger start to bite down, I clutch out the PTO. Much easier to rescue out the auger at this point. If the auger has sucked in, I disconnect the auger and stem, and use the front loader to dig it free. This assumes that I am out in the field with no backhoe available. I've learned that diligent attention is required when completing the hole or it can stick, losing valuable time.

 

[old and tired]

...the auger has sucked in, I disconnect the auger and stem...

I was warned early on about this and I have a 36" pipe wrench that I have used to unscrew the auger. Pretty easy with the right tool. I don't disconnect, just shut the tractor down and start to unscrew it!