Loader

[DMW]

What he said. More important than the parking brake, unless you have no implements attached. :laughing:

Never depend on the parking brake:
https://www.tractorbynet.com/forums/massey-ferguson-owning-operating/175414-gc-parking-brake-popped-out.html#post1998872

 

[lpakiz]

I have a brand new (well, 20 months old) MF 1754 and the loader valve and the cylinders will both allow sag overnight. The way i know the cyliders allow sag is i installed a hydraulic (high pressure) ball valve to be able to lock my loader in a raised (and potentially dangerous) position. Even with the ball valve closed, my loader will sag. I interpret this to mean the cylinders themselves are leaking a small amount of oil from the raise side of the cylinder piston to the lower side of the piston.
For comparison, I used to have a 1954 Case 400 tractor. (about 45 HP, but these horses were a bit bigger than the 54 horses Massey put under my new hood)
The 3-point (Eagle Hitch, to be more accurate) would hold up a darn heavy, 9 foot wide, 4 foot high home made back blade (made for snow) all summer. Never sagged an inch. Did i mention that blade was very heavy?
So my experience has been some cylinders hold, some dont

 

[aczlan]

I have a brand new (well, 20 months) MF 1754 and the loader valve and the cylinders will both allow sag overnight. The way i know the cyliders allow sag is i installed a hydraulic (high pressure) ball valve to be able to lock my loader in a raised (and potentially dangerous) position. Even with the ball valve closed, my loader will sag. I interpret this to mean the cylinders themselves are leaking a small amount of oil from the ”raise side of the cylinder piston to the “lower”side of the piston.
For comparison, I used to have a 1954 Case 400 tractor. (about 45 HP, but these horses were a bit bigger than the 54 horses Massey put under my new hood)
The 3-point (Eagle Hitch, to be more accurate) would hold a darn heavy, 9 foot wide, 4 foot high home made back blade (for snow) up all summer. Never sagged an inch.
So my experience has been some cylinders hold, some dont

If you think about it, it is not possible for your loader cylinders to leak down much at all without a leak in the loader valve.

As the cylinder retracts, the rod displaces hydraulic fluid and enough hydraulic fluid to match the displacement of the rod that goes in has to go somewhere.

If your ball valve on the base end is not leaking (along with the corresponding port on the loader valve) the only way for it to lower would be for it to either:
1. Leak past the base seal and then go out through the rod seal.
2. Leak past the base seal and then leak through the rod side of the hydraulic valve.

Otherwise, it is physically impossible for the loader lift cylinders to retract as hydraulic fluid is essentially incompressible and the fluid displaced by the rod as it retracts has to go somewhere.

Aaron Z

 

[lpakiz]

Aaron,
Yes, i understand that oil is not compressable. But the loader does sag. No doubt! We are in the middle of our maple syrup season here and i left a bundle of slab wood on the forks with the ball valve closed. I highly doubt (but theoetically possible, i suppose) that the new ball valve leaks. The forks are several inches lower this morning than they were last night.
Do you suppose that the bypassed oil (if that is whats occurring) does in fact pressurize the other side of the piston and THEN leaks thru the spool valve, and back to the resevoir?
That oil has to go someplace. A cubic inch of oil is a cubic inch of oil. It cant expand and it cant shrink.

 

[aczlan]

Do you suppose that the bypassed oil (if that is whats occurring) does in fact pressurize the other side of the piston and THEN leaks thru the spool valve, and back to the resevoir?

It has to, there is no other place for it to go unless it is leaking to the outside.

Aaron Z

 

[LD1]

A cubic inch of oil can't expand or shrink....And it cannot compress.

So to "sag" means you are pushing a solid round cylinder rod down into the barrel of the cylinder. The oil Thai it displaces most certainly has to go somewhere. And if there is no oil on the floor.....only place it can go is back trough the loader valve

 

[Diggin It]

There was a big thread on this topic not too long ago that had people defending their positions. .

I remember now ....


https://www.tractorbynet.com/forums...g/405046-front-bucket-dropping-overnight.html


.

 

[cdaigle430]

Its the nature of fluid, temperature, weight everything has an affect on it. Most will leak back to the reservoir and it is the reason why most equipment has a physical lock....why you must use jack stands when lifting a car, backhoe locks when transporting your tractor, even car transmissions have a physical lock.
I think the severity of the sag time wise can dictate if a part is defective....but sagging does not mean there is something wrong and you need to replace parts by definition.