hi, im working on a daewoo solar 170-111. it has a history of hydraulic seals leaking everyday! if im not wrong i think its due to hydraulic oil overheating. when the machine is working you can barely touch any hydraulic part. after replacing quite a number of o rings on the pump and control valve ive realised that even at idle without any operation the main pump gets hot first within 5 mins. ive replaced the hydraulic filters and had a brief look at the relief pressures they seem within range.oil cooler seems ok and i dont see any clogging.machine operates perfectly good power and doesnt load engine! hope someone can guide me through to solving this problem. cheers
hey anyone with such a problem??
When was the last time the hydraulic oil was changed. We noticed on our ex the oil was running hot, but improved considerably with an oil change. Ken
And depending on the daily air temperature where you're at, you might want to step up to an ISO AW 56 or even 68 hydraulic oil.
Had a similar problem with on of those solar daewoos, never managed to solve it. I almost changed all hydraulic pipes, orings, had alot of leaks on that machine, had the hydraulic pump repaired, Kawasaki twin pump, we sold it. In fact the machine is not bad at all, the engine runs smooth, wastes a little bit of fuel for its size, but it´s not a Caterpillar, or a Komatsu. Some say machines are all equal, only pay more because of the komatsu, CAT, hitachi badge, but when they got old, some do it much better.
im sure last oil change was ages ago. but at the moment i had drained all the oil for o rings change on the main pump and put the old one back temporarily to sort all the leakages. should i go for the hydraulic 46 or 68? the average temperature in nairobi is at 28 degrees C! could it be a stuck valve somewhere on the main control valve? cheers guys
Try the AW56. When you drain the system to change the oil, you might want to look over the oil cooler bypass valve if you haven't yet, it allows oil to flow around the cooler to avoid too much pressure damaging the cooler, can have a weak spring or stick open. The center joint seals can leak and cause heat when travelling, something to consider. Yes, a spool that is not centering properly can cause heat. Any chance you can get an infrared heat gun, you point it at an object and it tells you the temperature? Sometimes you can find heat sources with one that otherwise you would never locate.
ok yes was planning on the center joint seals as machine had difficulty moving. unfortunately dont have an infrared gun but will try to source. i have a doubt on the valve spools aswell how can i find out if a spool is not in center? could someone have mixed up one of the spools with another or are they all the same? once ive done with these will change hydraulic oil! cheers
I am not familiar with the Daewoo machines, but normally the spools are different, especially the travel and swing motor spools differ from the spools for cylinders. I doubt anyone would mix them up but you never know. Centering is mechanical with springs and rarely causes trouble, but again it can happen. Another thing to check is, assuming this machine has pilot controls, if any of the pilot lines to the main valve spools have residual pressure holding a spool off center, this is usually caused by a sticking plunger in the joystick control unit.
just ordered the center joint seals i should get them by tuesday. meanwhile i will check all the spools and look into pilot pressure to the control valve and seals on the joystick leaking aswell ill change and see if i see anything out of place. appreciate the help
Is the squash plate returning to idle correctly in the pump? Could explain how it gets hot even at idle.
well not sure how do i find out?
Check the pressure at idle
both pumps at idle showing 30 bar!
hey guys, changed center joint seals old ones were completely destroyed,put new joystick seals all seems fine no stciking in any of them,put some new o rings on the control valve and checked all spools the auxillary one was bit jammed so polished it and put it back, put in new hydraulic oil tellus 68 and checked all bypass valves! well unfortunately still same problem the hydraulic oil gets hot. but it is much better than before. i dont have an infrared temp gun but ive easily spotted the pump is the first part that gets hot.thats at idle with no operation! theres a pipe coming out of on top of the rear pump going into the hyd tank which immediately gets hot as soon as the machine starts! lol im anxious to get your reviews
The line that goes from the pump to the hydraulic tank is most likely the pump case drain. The fact that it gets hot almost immediately on startup would appear to suggest (provided everything else in the system is within spec) that the pump is leaking internally far more than allowable. That would indicate the need for a pump overhaul or replacement.
Nige is correct, but note the caveat: provided everything else in the system is within spec One question I have since I am not familiar with the Daewoos is, when in standby are the pumps unloaded to tank, in low pressure standby (load sense) or are they in high pressure standby, and is the control system working properly? If one or both pumps are building more pressure than they're supposed to with nowhere for output oil to flow, that may cause heating of the case drain flow. On the other hand I would think that wouldn't have much effect when working the machine.
Hi I have a 220 silt was wondering if you ever figured out the heating up issue?