Hi there, My machine has been temporarily losing the ability to lift the boom off the ground and travel. All the functions seem very weak when this is happening, so it maybe all functions are having almost no power and the boom lift and travel are not really or barely moving due to having a bit of resistance. This was occurring on the occasion, maybe 1 or 2 times a day but with this hot weather the past few days here in Australia it has been happening often, and affecting work. Thursday was the worst, being 42 degrees C out side, it was happening at least every 15 mins and it was incredibly annoying. It usually only happens for a few seconds but Thursday afternoon i was working it real hard and the boom went week and could not get it off the ground at all after trying for a few minutes! so had to pack up for the day. I thought it could be air in the lines because i did have this happen a few months back after i changed all the hydraulic oil, filter and strainer, but I do cycle the cylinders to bleed any air in the system and it still occurs no matter how often i do the hole air bleeding procedure. Occasionally when the machine hasn't been used in a few days when starting it up the hydraulic pump sounds like it has air in it for a about 2 seconds then sounds normal. If anyone could help with this i would really appreciate it.
You're going to be an expert on this machine when you get it running well. Did you end up getting a manual for it? Adam.
Yeah I've got a manual, I've probably read most of it buy now haha. I'm hoping this is the last problem to sort out, I'm tempted to sell it and get something a bit newer/ less hours though. This machine's been a bit of a headache.
Are you using it just for around the house or for business?
Well the main reason I bought it was for my 30 acre property I recently bought, and also for extra work when my metal fabrication business is quiet, but I've been getting more work than I expected with it. The customer i'm doing work for now sounds like he will have at least a few more weeks work for me on his property. So the machine has gone from being worked only 6 hours a week on my property, to now 40 hours per week.
I was just thinking about the first time it happened, it was just after i changed the oil and strainer. I was wondering, I did drain the control valve, from one of the lowest points on the valve block, could this have trapped air in it? causing this to happen? Anybody?
If anyone has even an idea please post it. I have the machine on a big job now and its constantly malfunctioning and lots of work to do with it, so any help would be appreciated.
How big is the file for the manual.
55mb
I was going to say send it to me and I will have a look but it's a bit big. I'd go through and make sure all the lines are nipped up just in case the pump is sucking air from somewhere.
Good idea, I will do that first thing tomorrow morning.
Is th hyd tank staying pressurized? There is a procedure for doing so after topping up oil.
My thoughts are that you are going to have to install some gauges in the hydraulic system to figure out what is going on inside it. It could be a pilot pressure problem, load sense issue, control or relief valve issue or even something stuck in a orifice somewhere. You won't have any air inside the system that will cause that. By this time if there were air anywhere it would be because something is leaking which would show. Your service manual will tell you where to plug in the gauges. Adapters might be a problem but you can make them. I custom built all mine by getting a cap or plug that will fit the Komatsu and then drilling and welding a standard fitting on to it that would fit my gauges. A lot of times I would install gauges with long hoses on the machine and then cable tie them somewhere where I could see them. Run the machine till it goes bug house and watch the gauges. That usually provide more evidence to figure out where to go next. Good Luck
It does stay pressurized when i'm working. But first thing in the morning it has lost its pressure in fact there is a slight suction in the tank, not sure if that is normal but I have pressurized the tank first thing after doing the air bleeding procedure on it, and it was malfunctioned a lot that day so didn't seem to help.
I had komatsu come out and check the pressures only about 100 hours ago, in fact the first time this malfunction happened was a couple of days after that, literally just after i changed the hydraulic oil, strainer and filter. Today I changed the hydraulic oil again and flushed the tank out in case the strainer was blocked up again and tightened up all the lines from the tank to the pump, so i'll see how it goes tomorrow. By the way it does have at least one leak from a hose going to the control valve. Thanks for the advise.
No luck with it so fair. My gut feeling is that the LS valve needs to be adjusted, like its not sensing the load. I don't have any gauges yet, does anyone know if I would cause any harm adjusting it with out gauges, just to see if increasing the presure differential fixes the problem?
I wouldn't recommend it if you don't understand the system but then again that's how we learned most of what we know. Make a mark somehow so you can put the valve back to the place you started if nothing changes.
Cool, I will try small adjustments Monday and see if there are any improvements. I will get a pressure gauge soon as well.
I adjusted the LS valve with no noticeable improvement, I did notice one more symptom that I think would be linked, sometimes the boom will lower much quicker toward the ground when left static and two times when heading down hill there was quite a bit of over travel after I stoped. Does that sound like the main relief valve could be sticking?
Check temp of oil....if it is over 165 degs f all kinds of neat stuff starts happening....valves get sticky...at 180 oring start going tacky...at 200 pumps start failing....I am very suspect that your oil is getting too hot.
Changing your oil to 68 weight and maybe adding a cooler would help....these machine were designed to run at way lower Temps then 45c. Your delta t (temp difference) between inlet of cooler and outlet would be terrible at 45c.. use a laser to measure temp of inlet and outlet.....bet that is your issue
Changing LS pressure changes response time and lubrication properties....it will not change the issues your having.
Thanks for that info, it's very helpful stuff to know, I was thinking of changing the oil from 46 to 68 but never tried. I will see if I can get a hold of a laser to test the temperatures. Here where I am in Australia the temperature is quickly changing, we will be getting much cooler temperatures which might not be the best time to change, but maybe it would still be a good idea, do you think it would still be good to run 68 oil? Considering the outside temperature wont be over 85deg f now and will be changing to around 60-70 f average here soon in a few months. Would 68 put more strain on the old hydraulic pump?
68 will work well from +5C. Below that I switch to 22 for winter.
Check the temp of oil....first that will tell story..if too hot...well you will have to fix it...85 f is still warm but it should wok on your oil as long as you have to lowered the viscosity by overheating it too much.
Oh yeah make sure your oil cooler is super clean....your fan and belts are tight. And that engine rad clean not restrictions air to oil cooler
HI BRO how are u i have komatsu excavater pc 30 MR-1 wherer is ajest pilot perassuer please help me thank you