What's hard on hydraulic systems?

[Bob_Trevithick]

What\'s hard on hydraulic systems?

As I was working with the front blade the other day, I noticed that if I lifted it fully, the engine would imediately begin to sound like it was working harder. So, of course, I would quickly release the SCV.

This led me to wonder.. what sort of things are rough on hydraulic systems? The only one I'm sure of is the one the manual mentions, having the rockshaft "speed of drop" valve locked and then trying to move it. (As an aside, why is it called a "rockshaft"?)

Any others? I'm totally new to hydraulics, and would just as soon learn as many lessons as I can the easy way! /w3tcompact/icons/smile.gif

Thanks,
Bob

Bob Trevithick

 

[MChalkley]

Re: What\'s hard on hydraulic systems?

Bob - This probably isn't what you were looking for, but by far the hardest thing on hydraulic systems is dirty oil. For the most part, if you keep the oil in good shape and the filter changed, hydraulic systems won't give you any trouble, other than normal abrasion and degradation of the hoses, etc. Hydraulic systems are extremely durable.

It is possible to super-heat oil by running it through a relief valve for a long period of time, which you would do if you, say, held the joystick long after the cylinders had fully extended/retracted.

Other things that definitely constitute abuse, though, are things like "ramming" the loader into stuff, but these kinds of things are more mechanical damage, even though it will often show up, not just in bent pins and linkages, but in blown seals.

MarkC

 

[Bob_Trevithick]

Re: What\'s hard on hydraulic systems?

<font color=blue>...Other things that definitely constitute abuse, though, are things like "ramming" the loader into stuff, but these kinds of things are more mechanical damage, even though it will often show up, not just in bent pins and linkages, but in blown seals.</font color=blue>

Thanks, Mark. That does help. I assume that really hard pushing with the front blade would be okay? Just no sudden impacts, right?

Bob Trevithick

 

[MChalkley]

Re: What\'s hard on hydraulic systems?

Exactly, Bob. It's the impacts that are really destructive.

When I had the custom work on my EF-5 done last week at D&E in Moncks Corner, SC, the founder of the company had a saying that I really liked. I tend to think of "enhancing" things as getting rid of the weak links, even though I knew, of course, that's not really happening from a real standpoint, only from a relative one. Anyway, his saying is "The weak link is going to move." Meaning, of course, that the best you can do, if you make something stronger, is make something else the weak link. What this has to do with hydraulics is this: with your average CUT, you can't get anywhere near enough traction to hurt any of the linkages, seals, etc. by pushing. But, if you add much bigger tires, ballast them, put on all kinds of extra weight, soup up the hydraulics, etc. as I did on my previous L4310, then you can damage things just by pushing, if you aren't careful. One area, in particular, that enhanced traction can damage loader parts is when using an aggressive tooth bar. If you dump the bucket all the way, sink the toothbar into the ground, are getting much better than "stock" traction, then backdrag with the toothbar to "scarify" hard ground or rake up roots, you can cause the dump/rollback cylinder seals to fail prematurely because you're putting so much stress on them. In effect, they're now not holding just the hydraulic pressure they were designed to hold, they're fighting to hold the force of all the traction the machine can generate.

MarkC

 

[RoyJackson]

Re: What\'s hard on hydraulic systems?

Dirty Hydraulic fluid can result from dirt getting into the system when one "tops" off the fluid...just make sure the area around the filler hole is clean.

I've seen burned fluid...but this was in very high stress situations (military aircraft...3000 psi systems).

If one was using their machine for commercial purposes, an oil cooler would be worthwhile...I don't think most of us will be using our machines that hard though. If fact, most of us may worry about running the systems too cool!

Bob, one very important thing...your hydraulic system operates in excess of 1000 psi. A pin hole leak will inject the fluid into your skin (did you ever get a shot by an air injection system while in the military service? that's 600 psi...). Hydraulic fluid is very toxic. So, if you learn one thing about hydraulics...learn the safety aspects!

As far as "sudden shocks"...well, don't be looking to do that, but it's going to happen occasionally. Your JD is built to take hard usage. Just make sure you keep the preventative maintenance schedule up to speed. You'll learn the limitations of your tractor as you go along...

<font color=purple> Roy Jackson
Windsor, PA </font color=purple>
[email]jacksonrm@suscom.net[/email]

 

[Bob_Trevithick]

Re: What\'s hard on hydraulic systems?

Mark,

Would I be correct in thinking that little of this would apply to someone using a front blade? The blade is connected directly to the frame, and the hydraulics only serve to raise, lower, or angle the blade. All pushing force is, I believe, directly to the frame. Although, of course, there must be significant pressure on the hydraulics that do the angling.. hmm...

I ask because I have a King Kutter dirt scoop with six sand bags in it, and some chains.. probably looking at around 600 lbs. of extra weight out back on the 3pt hitch. And I've been pushing some dirt, some small trees, some rocks, etc. I have R4's.

I don't do any ramming, but I do some serious pushing. Think I'm safe?

Thanks,
Bob

Bob Trevithick

 

[Bob_Trevithick]

Re: What\'s hard on hydraulic systems?

Hi Roy,

Yes, I've paid a lot of attention to the things my hydraulic system can do that's hard on me. I will even mention to my doctor that I have a tractor, and give him the number John Deere gives out for physicians dealing with hyrdaulic injuries. Thanks for the reminder!!

Best,
Bob

Bob Trevithick

 

[MChalkley]

Re: What\'s hard on hydraulic systems?

Bob - There's no doubt in my mind that you're safe, but some of the guys here might say I'm a little warped... /w3tcompact/icons/laugh.gif

Seriously, if you're just pushing, you're not going to hurt anything. I mean, the seals on your loader cylinders won't last as long as they would if you just started it every few days and ran it through its full range of motion then shut it off, but tractors aren't very useful that way.

I think the cautions might apply a little less to the blade than a bucket, but not too much less.

MarkC

 

[DFB]

Re: What\'s hard on hydraulic systems?

<font color=blue>As an aside, why is it called a "rockshaft"?</font color=blue>

Cuz that's what it does? /w3tcompact/icons/smile.gif


rock·shaft: A shaft that oscillates or rocks upon its bearings but does not revolve.

Bob, the diagram generalizes how that happens. Here a hydraulically activated piston rod pushes against a "crank" or lever arm thats splined to the "rockshaft" forcing it to partially rotate which causes the attached lift arm to raise.

But you can call it whatever you want. /w3tcompact/icons/wink.gif

DFB

 

[Bird]

Re: What\'s hard on hydraulic systems?

Bob, I'll bet most of us push (or pull for that matter) until we either run out of traction or run out of power./w3tcompact/icons/laugh.gif