my digger is acting really weird

[kiwiben]

I have this old late 1970's JSW 12 ton digger. It always had swing motor problems, among other problems. See my other thread if you're interested.

https://www.heavyequipmentforums.co......-my-Excavator-only-swings-in-one-direction

I never got to the bottom of that problem but simply topping up the hydraulic fluid to the proper level seemed to help alot, so i just carried on using it. But yesterday something weird happened. I had parked the digger on a steepish slope (The steepest i've ever parked it on), with the track motors directly downhill. Next day I went to use it and the swing motor would only go very weakly to the right, and not at all to the left. But to my surprise, the track motors were suddenly giving me full power for the first time ever.

Up until that day I could only drive up a hill for about 1-2 feet before the motor would begin to stall. Trying to use tracks in different direction was a waste of time too. I have just learnt to live with this problem. But now it's like I have 20 times the power in my tracks.

I was so excited i did some digging on the site using my tracks to orientate the bucket. After a while some of my swing function returned. (ie stronger to the right and now weakly but useably to the left.) For one glorious 5 minute period i even got full swing function in both directions. But then it died in both directions again.

The period of full function was after being on a level patch of ground for a while. not sure if this is just a coincidence. I am very new at this, and only mention the slope at all because it might have an influence... but i really have no idea. I am perplexed how my swing functions can change so radically from day to day. Let alone my miraculously revived track function.

Anybody think they know what's going on?

On a plus note, I have got through a ton of awesome work even with half my functions playing up. And thanks to all those who have solved problems for me in the past...

 

[Hendrik]

My guess is that you have junk floating around your hydraulics, blocking valves and such.
Get a new hydraulic filter(or 3), install it and cut open the old filter to check for crap.
If there is a lot of nasties in the filter, drain the hydraulic oil and then run it for a few hours, change filter and oil again. Open the hyd filter to see if there is still junk in the system.
Also I take it you are going to tighten up that track before going anywhere or is that picture taken whilst you had the track come off?

 

[overworked]

Sounds like u have blockage in tank on suction side

 

[Colorado Digger]

i love it!! clean filters and oil.. repeat over and over again. i know next to nothing about this subject but still love it

 

[kiwiben]

Hi,

A local guy said I may have a blockage in the suction from the tank, but I ignored him because i thought all functions would be impaired, not just the swing... don't bother explaining though, I will do my best to investigate and remedy.

As for the filters etc, if that is all it takes to fix my probs, i will do it ASAP!

 

[kiwiben]

and yeah hendrik, that track was off at the time... probably my greatest macho moment when I put it back on all by myself with nothing but a couple of planks, a rope, and a Mitsubishi Montero. But by the same token, I am such a novice I probably would drive with a track that loose, so don't stop asking me simple questions...

 

[kiwiben]

One last question Hendrik: When you say drain the Hyd oil and run it for a few hours... do you mean run it with no Hyd oil? Should i use the boom etc during this time (forgive my ignorance) to sort of make the crap flow through? And do you literally mean a few hours? That's a long time... I may get bored and slit my wrists for fun. Not to mention I have about $300 of hydraulic oil in there... don't make me throw it away... can I keep it and clean it? Please?

 

[bigmark234]

why not do what i did in my shop and build a recycler I got a suction pump and built a filter rack to accomadate dual filters to cycle the oil out of the machine into clean barrells.
the first filter is a simple racor with a sediment bowl and the second is a larger high efficiency filter.
I recycle low hour oil out of our equipment when I need to drop a pump or have indications of filtration problems.
I have saved uncounted dollars for our company and capturing the fluids is a good way to see what is in there.
I suction from the top of the tank with a probe long enough to reach the bottom and the pump is stout enough,
to pick up most if not all particulates.
You would be amazed at so some of the crap I have pulled out of these tanks.

One last question Hendrik: When you say drain the Hyd oil and run it for a few hours... do you mean run it with no Hyd oil? Should i use the boom etc during this time (forgive my ignorance) to sort of make the crap flow through? And do you literally mean a few hours? That's a long time... I may get bored and slit my wrists for fun. Not to mention I have about $300 of hydraulic oil in there... don't make me throw it away... can I keep it and clean it? Please?

 

[roadrunner81]

One last question Hendrik: When you say drain the Hyd oil and run it for a few hours... do you mean run it with no Hyd oil? Should i use the boom etc during this time (forgive my ignorance) to sort of make the crap flow through? And do you literally mean a few hours? That's a long time... I may get bored and slit my wrists for fun. Not to mention I have about $300 of hydraulic oil in there... don't make me throw it away... can I keep it and clean it? Please?

Don't run your machine without oil unless you want 12 tons of scrap! Hendrick is telling you that if your oil is contaminated to drain oil, change filters and then refill the system then run and check condition of fluid after the run time. May have to repeat the process to get clean fluid if system is heavily contaminated. Some hydraulic shops have a filter system they can bring out to clean fluid but the cost and your location may be a problem. Best thing to do at this point is to remove your filters and cut open for inspection. Make sure you change the suction filter as someone stated it may be plugged.

 

[Hendrik]

Don't run your machine without oil unless you want 12 tons of scrap! Hendrick is telling you that if your oil is contaminated to drain oil, change filters and then refill the system then run and check condition of fluid after the run time. May have to repeat the process to get clean fluid if system is heavily contaminated. Some hydraulic shops have a filter system they can bring out to clean fluid but the cost and your location may be a problem. Best thing to do at this point is to remove your filters and cut open for inspection. Make sure you change the suction filter as someone stated it may be plugged.

Yeah sorry, I did forget to mention that part about putting fresh oil in there.
As others have said, if you have a set up where you can filter the oil then you can get away with reusing oil (not the oil that has been in there since Jesus owned the machine but the fresh oil you'll be lovingly pouring into the old beasty).
End of the day you have to make the decision about what you do in regards to the oil. Perhaps just change the oil once but change the filter/s on a short schedule, however opening the filters will give you an idea of the level of contamination, may be your pump is wearing out? Remember that oil is cheaper than steel, particularly bits of steel that have very fine tolerances and are filled with O rings and have fancy names like pump and motor.
Another old school trick is to stick a magnet into the hyd oil tank, a magnet off a audio speaker is usually good. Although you'll need a way to retrieve it, to clean it and such. This is also done with auto transmissions and engines.
Whats the history of the machine, is it ex Japan?

 

[kiwiben]

Hi hendrik... i don't know the history, but it's been in NZ for at least 15 years. I like your magnet trick and will definitely do that. As it happens I was driving down the hill today to park on the flat where i can do all this fixing and the swing came back in both directions... this was good news, but I was determined to fix it for once and for all this time. So I carried on down the hill, pushing a huge ball of foliage ahead of me to burn later. I was then surprised by a strange smell, and turned around to see clouds of smoke pouring out of the engine bay. Oh brother... turns out my cooling fan belt broke, and the old girl got a bit hot. It was still running strong but I (you can see what a genius I am here) turned off the engine to investigate. I think/hope the smoke was caused by leaked oil all over the outside of the engine attempting to catch fire.

I will replace the belt and if it still works, continue with the hydraulics. If it doesn't work i will abandon it as a garden ornament I think... or sell it for scrap metal. What is the price of scrap metal per ton anyway? I may make a profit!

 

[kiwiben]

Ok, update: the motor still goes, a lucky escape there I think.

I then drained the hydraulic tank and cleaned it out with diesel. It was actually really clean anyway. Then I replaced the filter as suggested, replaced the Hyd oil, topped it up a bit for good measure, and you know what? the swing motor has not skipped a beat in about 6 hours running so far. It is still a bit weak in one direction but I ain't complaining. Thanks for everyone's help.

nest problem I will tackle is various small leaks in the hydraulic lines.... watch this space

 

[kiwiben]

Forgot to say, the Hydraulic oil itself was very dirty. I'm going to replace the new filter after a couple more hours... good idea?

 

[Hendrik]

Forgot to say, the Hydraulic oil itself was very dirty. I'm going to replace the new filter after a couple more hours... good idea?

Velly good idea, did you clean the suction filter?
There may also be inline mesh filters but hard to know without a service manual.

 

[kiwiben]

Hi Hendrik, not sure what the suction filter is.... is that a filter where the stuff leaves the hydraulic tank?

I do have a user's manual but it's a bit light on details. Most of the solutions offered in the troubleshooting section are "contact your local agent" It definitely doesn't mention a suction filter though...

 

[Chris5500]

Ben, do you happen to have the hydraulic schematic for this machine?

In one of your other threads I noticed you uploaded a page from the manual called the "Hydraulic System" which, at the end of the second paragraph says "(See Fig 2.5, Hydraulic circuit diagram)" - which is on the same page. This is not the type of diagram I asking for.

 

[kiwiben]

Hi, sorry, that's the only schematic I have unfortunately... anyone out there familiar with the JSW BH 40 hydraulics?

 

[Hendrik]

Yeah, it should be in the hydraulic tank and is a type of strainer to stop big nasties getting into the pump.