Case 580B 1974 - hoe boom keeps dropping

[JBP]

Hello. With the radiator replaced, on to the next problem.

The hoe boom will not stay in position. All of the other hydraulics are behaving.

The hoe boom has power, it just will not stay in position, just sinks until the hoe is resting on the ground. Figured before I tear into things I'd ask what are the most likely candidates and what to do about checking each one.

Still have 40-plus cedar stumps left in Aunties drive. Great stump digging weather too.

JBP

 

[1968 Case 580CK]

JBP......You notice any leaks under the tower controls? If no leaks, maybe some debri not allowing the valve to close, and thus the fluid keeps leaking past, and the boom goes down??

Leaks on the boom cylinder?

 

[El Hombre]

How long does it take to go from full up to the ground? My hoe is a year older than yours, and it's been leaking down for the whole 27 years I've owned it. Takes a couple of hours for mine to leak down. No way am I going to start messing around to 'fix' that....

 

[oldseabee]

Each circuit has an overload relief so if something drops on the boom it will go down instead of breaking. could be orings in the overload or some trash in it. Try backing it all the way off then power down, might blow the trash out first other wise either swap it with another one to see if the problem moves with it. Check your down pressure on power down, low pressure could be the over load.

 

[melben]

I have replaced many cylinder barrels on the machines with two boom cylinders, they are vulnerable to damage from swinging with the stabilizers up, many times dings and scuffing can be found on the bottom of the barrels. Most times the barrel and the scuffed piston will be required. Just another area to check.

 

[JBP]

68 Case 580K, I haven't noticed leaks around the tower. Photos of the tower controls.


.

The boom control valve is the leftmost. No leaks on the boom cylinders either. Also, the boom cylinders are not the originals, and are too long to let the boom retract enough to engage the 'lock'.

 

[JBP]

time to fall

El Hombre, when I retract the boom fully, it will stay up for a minute maybe. Once it starts the motion of going down, it only takes about 30 seconds. If that.

 

[JBP]

Each circuit has an overload relief so if something drops on the boom it will go down instead of breaking. could be orings in the overload or some trash in it. Try backing it all the way off then power down, might blow the trash out first other wise either swap it with another one to see if the problem moves with it. Check your down pressure on power down, low pressure could be the over load.

I'm very much the noob on these machines. Can you walk me through what you're saying to try here. What does 'backing it all the way off" mean?

So if you look at the photo I posted, you're saying I could swap the boom lines with the dipper lines on the tower and see if the problem stay with the boom or goes to the dipper. I'll give that a shot.

 

[JBP]

I have replaced many cylinder barrels on the machines with two boom cylinders, they are vulnerable to damage from swinging with the stabilizers up, many times dings and scuffing can be found on the bottom of the barrels. Most times the barrel and the scuffed piston will be required. Just another area to check.

Guilty. Like I said, a noob. I haven't done that too many times. But would driving the backhoe around without locking the boom upright all the time be something to accelerate the wear on the cylinders?

Should I look to get the right length cylinders so I can lock the boom upright? ka-ching I'd guess.

 

[oldseabee]

Look at the valve, and there should be something that looks lie a tall plug on each end of each valve section if it has a screw and locknut sticking out that would be the adjustment, otherwise it would be adjusted internally with shims, or may not be adjustable at all. In that take it out and check the orings or for a broken spring, all that fails, swap it out for the one on the opposite end of that valve section and see if the problem moves to the other end.

 

[JBP]

Well I tried to pull the spool out to check that first. Turns out the hydraulic feed line is right in the way below it. Then I had to split firewood for the rest of the day, so no more progress. Plus I need to buy some larger wrenches for the lines that are going into the valve/spool assembly. 40 stumps still.

JBP

 

[sheepfoot]

I would do what melben said first, check the boom cylinders. The 35 hoe on those machines will make contact with the stab legs and ding the tubes on the lift cylinders. The ding/contact will transfer to the inside of the tube and cause a cut/grove threw the piston and allow the boom to leak down.

 

[Shimmy1]

Should I look to get the right length cylinders so I can lock the boom upright? ka-ching I'd guess.

You're cylinders are fine, I would assume. You need to practice the "procedure" to put the boom "over-center". With the engine at about half throttle and the bucket on ground, pull back fully on boom lever. Just as it reaches the top, quickly move the lever to the down position. The boom will keep moving forward at which point the loop will drop over top hinge pin. It might take you a few tries, but once you get it, you'll be like "Wow, that is slick."

 

[JBP]

Shimmy1, the boom will not come back far enough for the hinge pins to get engaged in the hook loop. Ends up a couple of inches away and then the hydraulics reach 'end of stroke' or whatever the correct term is, and the engine starts struggling. And the boom hydraulic cylinders look to be fully retracted at that point. One thing that makes me figure they are mismatched is that besides this hoe being old as dirt, the current boom cylinders are a different shade of yellow than the whole backhoe itself, so they were swapped out at some point.

 

[Shimmy1]

Shimmy1, the boom will not come back far enough for the hinge pins to get engaged in the hook loop. Ends up a couple of inches away and then the hydraulics reach 'end of stroke' or whatever the correct term is, and the engine starts struggling. And the boom hydraulic cylinders look to be fully retracted at that point. One thing that makes me figure they are mismatched is that besides this hoe being old as dirt, the current boom cylinders are a different shade of yellow than the whole backhoe itself, so they were swapped out at some point.

You didn't fully understand my post. As you are RAISING the boom at about half throttle or better, just when it reaches fully up, you need to QUICKLY move the lever to the DOWN position. Here is a YouTube video.
https://youtu.be/FeEg19cnriU

 

[melben]

Warm the hydraulics up to a very warm temperature using the loader or another circuit, do not use the boom, when the oil is very warn then hold the boom up against relief and feel the feed pipes at the cylinders, if the pipe to one or the other gets warm the oil is bypassing the packing in that cylinder. Your best tools in diagnostics are your senses, those machines were my life, I would not go inside the valve till the cylinders are eliminated as the cause. Those valves WERE prone to losing orings on the secondaries and load check plugs .

The others are trying to tell you the method of over centering the hoe, do as they say, raise the boom at a fast rate, just when the boom comes close to top and is nearly stopped reverse the boom lever quickly and the boom cylinders will suck the boom to the lock position you have to raise it fast enough so it has momentum to carry it past center so the cylinders can pull it.

Mel

 

[D Grade]

As mentioned, lock the boom in travel lock when not in use (as it was designed) and tell us if youre still having issues.

 

[JBP]

You didn't fully understand my post. As you are RAISING the boom at about half throttle or better, just when it reaches fully up, you need to QUICKLY move the lever to the DOWN position. Here is a YouTube video.
https://youtu.be/FeEg19cnriU

Shimmy1,
Gotcha! I initially was not having any success with that. Reason being that one of the hydraulic lines was pushing the the lever release handle back. So even though I was getting the hoe back, it wasn't locking, and I was just thinking 'still didn't get it quite enough' each time. That's when I looked at the lever handle and the hydraulic line next to it and saw the spot rubbed clear through to the metal jacket braiding.

I had to snap off the lever handle at its base and reform it to accommodate the hydraulic line. The lever release handle (yellow rebar) in the photo was originally just going straight up. Even relocated it still makes contact.

And just like you said 'wow, that is slick'. Thanks a bunch for explaining that.

Thanks to all, I'll now try to pinpoint the droopy boom cause. Melben, in 1988 my calibrated hand failed to detect the warmth of a thermal battery activated on a chaff dispensing store on an F/A-18; we ended up dispensing a few pounds of aluminum chaff all over the flight line. I got to meet the squadron Commander that evening. Wasn't for dinner. I might have to ask my son to help with the hoe.

JBP
74 Case 580B

 

[melben]

I doubt there is quite as much on the line here, lol, if you do as I said , warm the reservoir to a very warm temperature with the loader, then with the boom locked over center, hold against relief for a while and feel the feed tubes for heat, if there is a cylinder fault even if the calibration of your fingers is off 5-10 % you will still be ok.

Mel

 

[JBP]

Well I got 8 stumps up before a hose burst. Still have not figured out the boom dropping problem. Beautiful day to do it.