Case 380CK Loader Hydraulics

[J_J]

I would recommend that you not take anything apart until you check the relief pressure.

Now, if you think the loader is slow, it is the volume of fluid that dictates the speed of operation.

Increase tractor rpm for max hyd speed on equipment

 

[cbattles]

Now, if you think the loader is slow, it is the volume of fluid that dictates the speed of operation.

Increase tractor rpm for max hyd speed on equipment

So essentially, if everything is working properly, the engine RPM should have no impact on the lifting capability, only the lifting speed?

 

[J_J]

Once the hyd pump is turning, the fluid has to go somewhere. You will have fluid flow if the pump is turning, and there is enough fluid at the input of the pump. Any pressure you see is caused by some resistance to the flow such as a cyl,, or hyd motor. The more resistance, the more pressure, until the pressure is relieved to protect the hyd system.

A worn pump or leaking hyd system, will not build up the specified pressure.

 

[DJ54]

Trouble shooting would be in the service manual. Each component section has it's own trouble shooting guide. Should be listed in the table of contents, at the front of each section.

I glanced at mine, while back at the shop. One of the items asked if both circuits seem to be slow, or just one. ie: Lift and bucket tilt, or just one of them. Causes listed, relief or check valve in the control stuck, or something holding it open, or a loose connection on the inlet side of the pump, causing it to suck air. Don't know if your reservoir has the little sight glass like mine, for oil level, but does the oil look foamy, milky, etc..?? If it appears to be foamy, may be sucking air at the rubber section connection.

Does it feel jerky, like it's lacking supply of oil.., sucking air? Or just smooth and slow...??

If you have the factory manual, the hydraulic trouble shooting guide should be in there, in that section. If not, I'd be glad to copy mine, and email to you, when I get a minute to do so...

 

[cbattles]

Don't know if your reservoir has the little sight glass like mine, for oil level, but does the oil look foamy, milky, etc..?? If it appears to be foamy, may be sucking air at the rubber section connection.

I don't know if I have a sight glass or not, I don't remember seeing one, but I'll check it out.

Does it feel jerky, like it's lacking supply of oil.., sucking air? Or just smooth and slow...??

It's definitely not jerky. The rest of it is tough because I just picked this machine up recently, so I have no point of reference.

Peak horsepower on my diesel is at 2200 RPM. At 2000-2200 RPM, I would describe the loader tilt and lift as smooth and (at least relatively) fast -- at least with the exception of some issues with the controls themselves being somewhat quirky.

However, at idle (say 600 RPM) the loader won't lift or tilt itself empty - not just slow, i mean literally it really won't move but maybe a few inches total. It gets progressively more powerful and faster as RPM increases.

For all I know, this could be 100% normal - but for some reason suspect that it's not - and I can't find anything to tell me otherwise.

 

[cbattles]

For all I know, this could be 100% normal - but for some reason suspect that it's not - and I can't find anything to tell me otherwise.

To add to this, if I was the type to just assume stuff was working correctly, I'd just rev up the engine and get on with my day. However, since I plan to have this kicking around for a while, I'd rather make sure it's correct before I beat on it. :thumbsup:

 

[DJ54]

Mine will easily lift itself off the ground at an idle.

Since it is not jerky, it may not be sucking air, but then who knows. With the filter in shambles, I'd suspect something in the valve body, and hopefully did not damage the pump.

My whole unit is all still good and tight. I consider myself lucky to find this '79 model with 2115 hours showing on the hour meter when I bought it. Both tach and hour meter work, and are original, from the looks of things.

Did you find the trouble shooting section in your manual..??

 

[cbattles]

Thanks, yeah, that's about the same number of hours as mine - but it seems to have treated the unit entirely differently. I'm just glad I picked it up on the cheap. :laughing:

Haven't had a chance to check the manual yet, but I'm sure I just skipped over it somehow.

I plan on changing the fluid, putting another new filter in it, and cleaning the valve body. Hopefully that will clear up some of the issue.

 

[J_J]

cbattles,

You have not mentioned the hyd pressure yet. That will give you the first clue if anything is wrong. Maybe someone put restrictors in the circuit.

 

[J_J]

Install a hyd gage and check the relief pressure. With no lever activated, you probably will not see any pressure, or very little, If the valve spools are good, the fluid will flow into the cyl and the gage will show how much pressure the system has at that moment. Engage the lift lever to max, and you should see the relief pressure. If it is correct, then you have other problems.

If a hyd system can produce up to the relief pressure, then the hyd system should lift the specified load. That is also assuming that the cyl are good also.