Can I rebuild the hydraulic pump for a Mitsubishi MT 372 D/Satoh 370 Beaver

[Alesandro]

That sounds to me like one or both of the lift cylinders are by-passing the pistons

Does that mean I should rebuild them both?

You say you "fixed one of the cylinders" on the loader - which one?

I rebuild the single that performs the bucket tilt, only reason I did that was because it was leaking fluid from the cylinder, it performed the same before and after the rebuild.

If you lift the bucket up as high as it goes, how long does it take for it to fall on its own back down (if it does)?

Not fast, I don't know if it does at all. I will lift the bucket and let you know.

 

[Alesandro]

If you lift the bucket up as high as it goes, how long does it take for it to fall on its own back down (if it does)?

HUH, I never noticed it before but it drops slowly, maybe an .5-.75" a minute Is any drop acceptable?

 

[Billrog]

At that rate the pistons aren't in that bad of shape I've had them worse than that and it never effected lifting power or speed. Could have a problem in you control since it works at the end of the stroke.

 

[Ilikeurtractor]

.5-.75"/minute seems excessive to me for an empty bucket. I'd go after the two lift cylinders. Maybe only one is "bad" and likely one is worse than the other but you might as well do them both. The fact your pump can build to relief pressure (1800 psig) and when actuating the main lift only registers around 900 indicates something is bypassing and I'm making the assumption it isn't a relief valve based on your description. If one cylinder is bypassing a lot more than the other the bucket can still be held up (mostly, in this case) by the "good" cylinder but the one good cylinder can't get enough pressure built up to lift higher because the other is robbing the pressure away.

 

[Alesandro]

I will take apart the bucket cylinders today and hopefully have them rebuilt later today or tomorrow. I'll post with the results when done.

Thanks for all the help guys!

 

[Alesandro]

I took apart the bucket cylinders today and found the problem. My seals are blown on both pistons. I took them to my hydraulic place and they don't have those in stock I should have the parts needed by Monday and I'll post results of how the bucket works after that, I assume it's gonna be like a new machine.

 

[PILOON]

Mitsubishi actually sold a kit at one time to power equipment from the crankshaft.
Knowing that I made up a 3 legged adapter using a Ujoint and coupled that to a hydraulic pump that is now dedicated power for my FEL
This speeded up my FEL operations and left the engine pump for 3 point and other chores.

The factory engine pump was pathetically slow and my MT180 now thinks it is a skid steer, and with my tooth bar works like one.

For sure a front crank adapted pump will be miles less costly than the very rare original as (if U find one) plus used becomes another option.
In my case my FEL had its own built in reservoir in one of the posts. I also installed an in line filter as I had one on hand.
Has been operating flawlessly for the 18 years that I have had it.

I have seen many other brands with aftermarket FELs that are plumbed that way.

 

[Alesandro]

Mitsubishi actually sold a kit at one time to power equipment from the crankshaft.
Knowing that I made up a 3 legged adapter using a Ujoint and coupled that to a hydraulic pump that is now dedicated power for my FEL
This speeded up my FEL operations and left the engine pump for 3 point and other chores.

The factory engine pump was pathetically slow and my MT180 now thinks it is a skid steer, and with my tooth bar works like one.

For sure a front crank adapted pump will be miles less costly than the very rare original as (if U find one) plus used becomes another option.
In my case my FEL had its own built in reservoir in one of the posts. I also installed an in line filter as I had one on hand.
Has been operating flawlessly for the 18 years that I have had it.

I have seen many other brands with aftermarket FELs that are plumbed that way.

PILOON;

I think I can envision what you wrote but can you post a picture of your setup? I'm new to all this and I would like to wrap my head around what you wrote.

Thanks for the help.

 

[Ilikeurtractor]

I took apart the bucket cylinders today and found the problem. My seals are blown on both pistons. I took them to my hydraulic place and they don't have those in stock I should have the parts needed by Monday and I'll post results of how the bucket works after that, I assume it's gonna be like a new machine.

It is possible the control valve is bypassing as well but the cylinders clearly need some attention. From my experience, control valves are less likely to be the problem. Why do the rods/pistons appear to be different sizes? Aren't they the same on both sides of the loader?

 

[Alesandro]

Why do the rods/pistons appear to be different sizes? Aren't they the same on both sides of the loader?

I believe the size difference is an optical illusion. From the picture they look pretty different in size but I didn't notice anything out of the norm when I was handling them. While I didn't take measurements I did label each side so that I wouldn't get them mixed up and so that I could possibly "track" any performance differences.