ex100.2 bucket cylinder weak & slooooooowwww

[santikko]

yes, it is tracking straight, as ive been driving it. pilot system has it own pump, and im pretty sure it is somewhere in pilot system, because bucket does have its power left, its just slow. so the spool valve is not opening for some reason. what is funny it is like ten times faster when i pull the digging boom or some other to full movement and keep the lever pulled. i just dont get it how can that make difference. tomorrow ill go to hydraulics shop to get some parts and ill take now the parts to get the pressure meter engaged. the pilot pressure should be near 50bar, am i right?

 

[HDMRice]

I'm not familiar with this machine, but most machines have some way of upstroking or destroking the pumps depending on the demand. This is sometimes done through a load sensing function. Someone earlier mention a possible issue with the "resolver" network, thats how caterpillar does it in some of its machines. Its just a series of shuttle valves that lets the highest pressure through.

A red flag to an issue with the resolver network is when one function is very slow, but speeds up when another function is used at the same time.

Might be your issue

 

[GregD1]

It`s been a few years since I`ve been into one, but whatever a "resolver" is, there isn`t one on a Hitachi.

 

[johnnyboy]

Maybe you should do speed test on all functions because flow combiner will compensate for a bad pump making it seem that other functions are better than they really are. Does this machine track strait?

Sorry what I meant to ask is was is one track slower than the other, lift tracks one at a time and count seconds to do 3 revs then do the other side and compare if one is slower than I think pump or regulator, if this is the case the put gauge on main pressure port of pumps if it makes relief pressure than its good and your maybe looking at regulator problem. Or possibly O-rings on control spools shot on pressure getting by and not stroking spool or some junk physically stopping spool movement. If it is the spool getting hung up than your flow sense will be low and will stroke the pump.I chased a similar problem around a 300-3 and it ended up being a regulator problem.

 

[santikko]

today got the t fittings to measure some pressures. then ill tell you do i have enough pilot pressure. it is just like the spool valve is not opening. it does not load the engine until the movement reaches a top, then it strokes the engine as normal. really weird, but now ill get some facts with the gauge. i will do the track test when i get there. i just dont believe its the pump because it started in a snap.

 

[santikko]

The pilotpressure is fine. Also the cylinders gaskets seems fine, bucket stands in place even if i pull the excavator with it. I changed the shuttle valves between an other function, still quiet. Next ill do the tracking test. Where is this regulator, and what is its real full name? Could search for some info. Could it be fixed, or replaced only. How much work it causes? Thanks really much this far, yours help is worth of gold to me. Johnnyboy, tell me about your 300.3 case?

 

[johnnyboy]

If your finding metal parts in the control valve than maybe you should have a look in filter too. How do all other functions work? one weak track?

 

[santikko]

Did not yet test the tracks with second counter, just drove it a bit and it feels like its going straight. Also tried some boom functions when tracking, didnt notice any mistracking, only slows down when boom is moved. How did johnnyboy your hitachi story go? I really do not know where to look to solve this problem. Spool valve moves freely when its taken off, it has got pilot pressure, shuttle valves have been changed.

 

[johnnyboy]

Did not yet test the tracks with second counter, just drove it a bit and it feels like its going straight. Also tried some boom functions when tracking, didnt notice any mistracking, only slows down when boom is moved. How did johnnyboy your hitachi story go? I really do not know where to look to solve this problem. Spool valve moves freely when its taken off, it has got pilot pressure, shuttle valves have been changed.

Our problem initially was a bad pump, then reman pump we got had regulator problem so it was hard to diagnose. Machine will still track strait with one weak pump because it has flow combiner in control valve- this is why you need to test track circuits seperatly. One pump for each track. I have never worked on a ex100 either so I'm not familiar with this machine. With dual pumps there is a one pump, two pump stroke -meaning bucket out=one pump and bucket in=two pumps. If your tracks are equally powerful when used individually than both pumps are probably good. Try switching pilot lines at control valve from arm to bucket you will have to swap all four lines and see if that makes bucket work as it should.

https://www.heavyequipmentforums.co...00-3c-mistracking-and-slow-swing&goto=newpost here is link

 

[santikko]

With pilot lines do you mean pipings going from valve block to cylinders? I suppose thats next thing o should do. If the bucket works normally with other functions pipings, the problem is in valve block somewhere. Just cant reaconize where. Well, theres like three weeks when we should have allmost ten kilometers

 

[santikko]

With pilot lines do you mean pipings going from valve block to cylinders? I suppose thats next thing o should do. If the bucket works normally with other functions pipings, the problem is in valve block somewhere. Just cant reaconize where. Well, theres like three weeks when we should have allmost ten kilometers ditch digged and havent even started yet.

 

[johnnyboy]

With pilot lines do you mean pipings going from valve block to cylinders? I suppose thats next thing o should do. If the bucket works normally with other functions pipings, the problem is in valve block somewhere. Just cant reaconize where. Well, theres like three weeks when we should have allmost ten kilometers

No not pipings but the pilot lines that control spool movement, there should be one on top and one on bottom that push spool back and forth, and remember that I'm just assuming your machine is similar to the 300. Any chance you could take a pic of pumps and regulator lines on top?

 

[santikko]

Have tried it, and also measured pilot pressures from spool cap. Pressures were normal, and bucket did not move with another pilot line. I think problem is in main valve bank, but have no idea where in it. I changed shuttlevalves which are situated close the pipe outlets, one for each pipe. Took them from the next spool and changed them between. Nothing happened. Cant understand. I scare that there is some broken line inside the valvebank because of the little metal pieces at one spool valve, but dont know how it could be tested. But feels strange still because there is still power in bucket just only not flow. Like a broken shuttle valve.

 

[johnnyboy]

just to clarify how are all other functions? Also you only have one variable pump- is this correct?

 

[santikko]

Correct, all other functions are fine, just the upperstructure turn has some issues. Im really not sure about the pump, but as i know there is one variable pump.

 

[pfpm]

Don't know about the ex 100 but on 120 to 220 ther are proportional valves on some spools.
Thier function is to restrict the flow on one circuit so that other functions will work. If one was closed it would only allow a small amount of oil through. From memory they are either in front or behind the bucket spool. Have another look at your shuttle valves and not just the one next to the bucket spool.
On a the bigger models there are also solenoid valves that overide the proportional valve,these can be identified by looking fo tubeing that goes from a solenoid bank tothese proportional valves. If your machine has a steel tube going into the area next to the bucket spool disconnect it , plug the tube end and give it a try
You have metal in hyd system so you need to find where it came from. Excavators a notorious for the slew motor finding contamination because the anti cav line suck unfiltered oil into the motor when decellerating from slew.

Regards Mike

 

[santikko]

There is this solenoid valve bank or something next to the main valve bank.http://m.ebay.com/itm?itemId=251384254252 theres solenoids like this six or eight peaces. Their name is proportional something. I just dont know this solenoid valve banks function how does it work and where it effects. Could the problem be in these solenoids? Im writing with my phone, i have the pictures and partlists at home in my laptop so i cant now show you what i mean. Ive heard that the hydraulics are same in ex100 and ex120. And some of the terms i use might be wrong, pictures would help a lot in this thread so i could be sure we are talking about the same things.

 

[santikko]

I went and took a look at the valves and thinked your words, there is going little steel pipe from each spool to this solenoid valve bank where is six solenoids or proportional valves. I swear the problem is in there. Im sure. So if i unplug the pipe and plug it, it should make a difference? Im not sure do i have parts to plug it so i open few valves and look inside. There should find a little spool valves inside. Thank you mike, ive been thinking a long time this solenoid valves function.

 

[pfpm]

Be very careful with these valves. The solenoid does not do anything under single operation of a function. Not sure the exact sequence but it is something like when you move two spools the lower pressure one will close off a bit and also when you change dig functions it sends a different pressure to these. I would look at the section where they screw into the main control valve first. Maybe swap a couple around or unplug the wires.

regards Mike.

 

[santikko]

Thanks mike. Took off the spools that the solenoid valve operates at main valve, nothing unusual. Took off two solenoids from the solenoid valve bank, took a look at them, everything seemed fine. Had no multimeter by my hands so i swapped the solenoids places, no cure. Then i unplugged the wires from the solenoid that works for the bucket spool, and it woke up! Theres some problem with the wirings maybe, next time ill take my multimeter with me so i can do some research, but i just left the wires unplugged so far, seems that it does not make any harm if unplugged. Thank you very much guys, your advices helps me step by step closer to learn this machines parts and functions and how one effects the other. Thumbs up for these forums and helpful people. Someone like me can learn a lot from here and save thousands and thousands of euros.