Trying to iron out some minor issues. I've run the machine about 80 hrs over the last year since buying it. I didn't have any errant hydraulic noises in cold weather, now that it's summer, hydraulics at operating temp (78-80 degs celcius), I get a whine mostly in the right control bucket curl/uncurl and boom down while feathering control, occasionally on the left control arm in/out. When selecting full travel it is quiet. Wondering if rebuilding the (joystick) pilot control valves would be the cure. I'm running 46w hydraulic oil. Somebody has inhibited the computer hydraulic control system in it's past (cut out the solenoid control harness), doesn't seem to effect operation, just has no work mode control. Looked at correcting that, but it looks like a deep money pit, and it performs well as is. Thanks
You mean joystick whinning at fine control?
Yes.
Is joystick stiff? Check outlet pressure from joystick using a tee
There is no change in joystick feel, other than the buzzing when it whines. Oddly it comes and goes when at those temperatures, but generally repeatable. I suspect teeing into the associated pilot port on the main control valve would be easiest due to space and access. Would I be looking for fluctuations in pressure or ...?
If the min pressure required to move the main spool in the vontrol valve is reached so no need to care about the whine no more
Thanks, I'll test it when I can get the fittings together and a bit of time. I didn't consider pressure as a potential cause.
Is the problem causing any difficulties when operating the machine? Does it sound like a hissing noise as though oil is by passing the spool? To be honest unless it's causing problems i wouldn't worry about it. If you do want to do checks i'd try swapping the right hand pilot valve with the left. See if the problems changes sides. Then i'd try checking the primary and secondary pilot pressures. There's no spec in the manual for this but the newer Hitachi's have this test. Get the temp up to normal. Check the pilot pressure by teeing inline somewhere near the pilot pump and record the pressure. Then tee in to each service causing the issue. Ideally at the control valve as that's the easiest place. Dead end the circuit and hold the lever whilst noting the pilot pressure acting on the spool. This is the secondary pressure and shouldn't be much more than 2-3 bar lower than the pilot pressure. If it is it could indicate oil by passing the spools in the pilot control valve. But because the pilot system works off low pressure it may be difficult to diagnose an issue purely by pressure readings. That's why if it's not causing you problems i wouldn't worry as you could end up spending money for nothing.
It doesn't effect operation, as it only occurs while feathering the control, so more joystick always yields more movement. I do find it rather annoying though, in an otherwise very pleasant experience. If I can identify the problem and then decide too expensive, I will be happy. Sometimes such annoyances turn out to be a simple fix. Replacing the pilot pump or a pilot control valve reseal isn't unreasonable to me, but I won't do it on spec. A pilot controlled hyd. system, unfortunately, hasn't crossed my path before so I'm appreciating any opinions given. I do my own wrenching. I will check the pressure drop first, makes good sense and a rather quick test. Swapping controls is a bit more involved, and the whine only shows up when outside temps are hot enough, oil must have to get up to the 80 deg. celcius. We've been plagued with a cool wet summer as of late. But I will swap them if the pressures don't show any glaring deficiencies. Thank you
A very interesting thread. I too have an EX200-1 and suspect the noise I get from the pilot controls is exactly the same as 200lc1 gets. Another guy here had one and when he saw me replacing the factory nylon/plastic pilot lines with wire braid hose told me that I would get noise/ vibrations. I told him he was nuts or had smoked a bad batch of laughing lettuce. I can not say with absolute certainty that the wire braid hose caused the problem, in fact it makes no sense to me at all. But I do know for sure that I only get the noise on functions that have had the original lines replaced. I had thought there may have been a problem with the manifold, I think Hitachi calls it an anti shock valve that the pilot lines go through. But plumbed in an axillary foot operated pilot valve (Monsun Tison / Voac / Parker) directly to the main valve and have had on occasion had this valve do the same thing. We have put over 10,000 hours on this machine, so have come to accept the noise and have never seen any evidence of reduced or poor performance. Once again, wire braided hose causing this problem makes no sense to me. If some one can explain what is going on, I would be delighted. If I am completely wrong and it is just coincidence that the noise and wire braided hose are related, I would like to know that too Thanks
That's interesting, not what I like to hear, but interesting. I would guess all of my pilot lines are changed, didn't see any nylon lines in there (or anything that looked low pressure). I have heard of circuit design and routing causing noise, maybe the hose liner material or inner diameter is all that it would take. I'm curious what the spec'd hose is. I wouldn't rush out and change them all, but I do have some deteriorated ones that may need changing eventually. My gut says that it's something wear related in the primary components of the circuit. It is interesting that this isn't an isolated case.
I checked my machine today and found an original nylon hose in the shed. Hitachi part #4203057 stamped on one fitting. Name on the hose is: Nita-Moore Synflex Hose 1000-06. A fair bit of stuff on Google about that. In looking through the Aeroquip and other catalogs, some of those SAE 100R7 or R8 hoses must be similar. For whatever reason the lines that go from the shockless valve to the main valve are not the same. They look like regular lines and fittings, but when you hit them with a magnet, no steel, just nylon. The only name and number I could easily get was off a 1/4 inch line that goes to the accumulator, but apart from the size, looks absolutely the same as those from the shockless to main valve. It is a Yokohama N176. Online specs for that hose look to be identical to the Nita hose. While at it, I put the magnet on the drain lines from the swing gearbox and centre swivel. No steel again as could probably be expected for tank pressure, BUT both the hose and crimped fittings look identical to regular one or two wire hose. I would bet a few cold ones that you still have nylon lines after the shockless valve. I have never had one of those fail. Spent a bit of time today looking at the parts drawing for that shockless valve. Lots of springs and spools, but looks like separate for each line, so chances of having all springs broken etc. must be remote. If you don`t have the supplementary parts book for hydraulic components, you can look at a 790D on the Deere parts site. Exact same pumps and valves, just turn the pumps faster to give greater flow. Like yourself, I know for sure that the problem is temperature dependent. All else is just opinion on my part, but I think my pilot pump is good I know it is at cold temperatures. The next time I run it, will leave the pressure gauge on with an extension hose into the cab. I don`t think oil viscosity is the problem either. Years ago I bought another wrist control pilot valve, albeit used, made no difference what so ever.The fact that a shockless valve is used would suggest that the pressure change signal from the pilot controllers is not that clean, so perhaps it is not impossible that hose structure is important. Years ago I replaced a failed line with 1/4 inch 2 wire as it was all i had. The problem was definitely worse than with 3/8 1 wire. I have another mystery on another machine that needs to be solved first, so please post if you come up with something. Would be happy to ship to you that wrist valve and the original hose if you thought that might help. Thanks John
Like you say, temperature related. Had a similar problem with EX150-1 only at high temps. That operating temp of 78 - 80 degrees C is getting right up there, at 82 degrees you start doing damage to o rings hoses etc. Operating oil temp should <40 degrees above ambient temperature, Cured mine by external oil cooler clean out, new oil seal on pump input shaft as believed it was sucking air ( possible oil airation at temperature) Also check relief and over load valves in main valve block for damage, leakage and reset operating pressures as per specs. As with any hydraulic system, any leakage or bypass from high pressure to low pressure with out doing any work equals heat. After that tune up I can go out on a 30 degree day and only get 63 degree Hyd temp and no more buzz in the pilot control.
Good points. Have never monitored temperature as much as I should have. Figured they all ran hot, a friend had a brand new Komatsu 200-3 and by comparison the Ex 200 was actually cool. I have a PC120-3, It runs ultra cool. But having trouble with boom cylinder oil leaks, new heads, magna fluxed heads, re chromed the rods, the only thing left is to replace the load check/ anticavitation valve for the boom, but had to figure that out myself, none of the service guys had a clue, That is priority #1. On the Ex200, have always used oil with the best viscosity index available, but I guess thermal expansion of components, orifices etc. must be a factor. Do not recall ever having seen an external cooler on standard machines here, only on machines with processors or hammers etc. Thanks John
Thanks for all the good points. Gives me some areas to focus on. Unfortunately I don't get to run the machine regularly, hop on it when other farm priorities and work allow. It's an old machine and appears to have been treated as such, I've been slowly bringing it back to a reasonable state of maintenance. This cooling deficiency only came up with the summer temps, I didn't have the machine before fall to compare. Freewest, any chance I could get you to measure your swingdrive dipstick full mark to stopper/cap. No rush, just want to make sure I'm running a reasonable level of oil. No other first gen machines around here for me to check. I'll look into those hose specs, thanks. I will keep you posted with what I find, have a couple other priority projects ahead of it now. This gives me some ideas to strategize with. Thanks again
Fill level for 200LC1 swing gearbox Tried a pm, but most likely did not go thru, will have to get some kids to show me how to do that It has stopped raining, so got to measure today. On this machine which is apparently near the end of the production run with SN 50536, the dipstick tube sticks up 8 3/4 inches above the housing and the fill mark on the dipstick is 10 5/8 below the top of the dipstick tube. The filler plug is 180 degrees from the dipstick and 3/4 pipe, but of course BSPT and not NPT. I took that out and the oil level is 2 1/4 below the top of the housing. The factory dipstick is very good with rubber grommets to keep out dust etc. Difference between fill and add is only 3/8 of an inch. Need to keep the oil over an upper bearing is my guess. Keep in mind, that these machines are not really the first generation. There were certainly several hundred UHO7 and UH181 machines in BC. I suspect several parts would bolt onto an EX200-1 Hope this helps John
Got a little time to push the "restoration" forward. Checked the three pump pressures cold and hot, all at the high end of spec. Pressure dropped only a bit with heat. Checked the pressure drop across the pilot valve on one of the whining functions, no notable pressure loss. Watch the pressure on the pilot system when it whines, no visible changes in pressure. Maybe it's the hoses, I don't know. Added a dual 12v cooling fan, wired in series, onto the cooling system (had it laying around). Brought the oil temp down 10-15c, think I'll leave them on to add longevity to the hydraulic system. Good enough for now, walked it 1/2 mile from my shop where I'm clearing for hayland, I don't think it can find it's way back on it's own Freewest, thanks for the info, I resealed my swingdrive and brazed a stopper on the dipstick at what you measured. Basically puts the oil level at the top of the upper planetary. Cheers
The rubber wire braid hose will expand slightly with heat and pressure. The nylon or Synflex R8 thermo plastic hose will not expand with heat or pressure.
Where did you put the extra fans? Do you still have supplementary coolers from when it ran a processor?. Have no way of knowing for sure, but have thought for a while that one of the hose types had a micro accumulator effect. Had thought that the nylon lines would be more susceptible to just enough stretch to screw up the metering. But looks like I have that backwards. The other thing I don`t understand well is the function of that anti shock valve/ manifold. That is something that I hope to look at closer this winter. Good to hear that you are making restoration progress. This week is change water pump time for me. No exchanges available and too lazy/stupid to rebuild the old one. The Isuzu industrial dealer was $200 cheaper than Wajax.
Interesting on the water pump, sometimes you need to hit the easy button (who is the dealer, for future reference). Oil cooler is stacked on the rad, about the same size. Parts book shows it as stock. The fans fit across the bottom half, below the a/c condenser, which, takes up the upper half. A flexalite remnant from a v8 Toyota conversion I did eons past. Haven't delved into the antishock manifold myself, takes a bit to get my head wrapped around the service manual sometimes, especially with the hydraulics. Sometimes it takes a couple beer to really get to the heart of the matter.
The Alberta Isuzu industrial dealer that I have been to is Westquip Diesel Sales. There may be others, but these guys have been good. Not very busy, so keen to talk and they do know 6BDT engines and like them. After talking with them about tier 4 problems on gensets etc., my resolve to stay away from that was confirmed. Have always said that if I was young and rich, ( but strike out on both), would totally re build an older machine in preference to a new one. But this week was a bit of a wake up call on costs. Did the whole cooling system. Water pump, about $750, have the rad power flushed and checked etc, $496. Decided to replace rad hoses although the originals were still reasonable, but 26 years old. Wajax started at over $400 for one hose, but came down to $421 for both, but have to come from Atlanta. Should of phoned Kamloops, as I know on truck parts there can be quite a bit of difference between different branches/dealers for the same item.
Good day all, hate to open a old thread, but my 200-1 makes the exact same noise as 200lc1 s . did anyone ever find a fix, thread went off topic a bit, just thought someone may have some imput. Thank you.
Can't say as I've pursued it any further. With everything in spec, and it operating fine, I chalked it up to old age. Let me know if you find success.
thanks I will keep you posted
Ever get anywhere solving the pilot line noise? I had a few pilot lines go so I replaced 9 at once to get rid of most of the original lines and once it warms up I get the same noise and vibe. It’s on an EX150 but exactly the same as was described here.
The whining noise you're experiencing in your Hitachi EX200LC-1 excavator's hydraulic controls during feathering might indeed be related to the pilot control valves. Over time, seals and components can wear, leading to such noises. Before considering a full rebuild, you can try flushing the hydraulic system to ensure there are no contaminants affecting performance. If the noise persists, a rebuild may be necessary. Since your excavator's computer hydraulic control system has been modified, seeking professional assistance from a qualified technician with experience in hydraulic systems is recommended. They can diagnose the issue accurately and provide guidance on potential repairs or replacements.