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Hydraulic loss of power

cpmartin1989 ยท 2022-04-06 13:01

Morning all, I have Komatsu PC35R-8 Serial #F21286. The machine has 1100 hours on it, had no issues when I purchased it approx 3 months ago. I does have one leaking cylinder but not critical to operation and not a significant loss. Recently I seam to lose power after the machine is on and hydro heats up. First indication was the left track seems to lose power, (tracks straight though) replaced final drive oil all looked to be good, no shavings. I borrowed a thermal imaging gun from work and it appears that the very bottom hose coming into the 9-spool control valve is getting warm quickly. Along with what I believe to be position 3 (pressure compensation valve R (boom swing - blade). Reading the operators manual it suggested cleaning the suction filter, I was a little hesitative as it said this was a 2000hr maintenance item. I did clean and refill with proper oil (like 300 bucks worth of fluid) did not fix the issue. It sounds like a small hiss coming from the 9 spool valve, I think maybe a valve may be stuck open/partially open/etc. I am not ready to rip into that valve body until I can come up with a really refined idea of what it could be. I will be more than happy to answer any questions anyone has.

Replies13
  1. #1Nige2022-04-06 13:14

    I'll let the Komatsu experts chime in on the tehcnical side, but the fact that your machine only has 1100 service hours to date and the suction filter is a allegedly a "2000-hour maintenance item" are unrelated. It's usually stated as "2000 service hours or 1 year, whichever comes first", and I'll bet your machine is way over one year old. I would have recommended that you did it - while changing the oil would have been the perfect opportunity.

  2. #2heymccall2022-04-06 23:22

    What oil grade/ type did you install? As for the running hot, is the cooling stack (radiator and oil cooler) clean? Is all the foam in place around the radiator perimeter? Fan belts tight? Of you stall the stick in along with bucket curl, how bad it bog down? Any exhaust smoke under said load?

  3. #3John C.2022-04-07 11:25

    Tracking problems have lots of causes. Leaking seals in the swivel, wear in the travel motor, main hydraulic pumps out of adjustment. Power problems start at the engine. Partially plugged fuel strainers and filters, air filters plugged and bad fuel. Localized heat usually means nothing depending on what you are doing with the machine. Temps on the monitor panel are where you would start looking for problems as they tell the story of something heating beyond the cooling capacity or the radiators. Your machine is a 2003 model, 19 years old, which indicates that either the hour meter reading does not show total machine hours or that it has been sitting unused for many years. In either case, the possibilities of problems are very high. You will just have to identify and deal with them as you use the machine.

  4. #4cpmartin19892022-04-12 15:08

    Hey John, the hour meter does work. The person who had it before me used it very rarely as they own a construction company and a lot of different pieces of equipment this was more or less used as his personal mini that he used around his own property. Only gauges on this are fuel and coolant, which is does run a little warm. I think that is because the fan belt could certainly stand to be replaced. Not sure if it can cause that big of issues considering it is still intact and operating.

  5. #5cpmartin19892022-04-12 15:10

    Fan belt for sure could be replaced its worn and it does seem to have a lot of deflection. Foam pieces appear to be in place, I have not noticed the engine bogging down at all, strictly just a loss in hydro power. I have replaced the fuel filter. The fuel pre cleaner i have not though

  6. #6cpmartin19892022-04-12 15:12

    Sorry type of oil is Castrol HySpin

  7. #7heymccall2022-04-12 18:42

    32, 46, or 68 iso?

  8. #8cpmartin19892022-04-13 13:28

    I was told by previous owner that the only oil they ever used was ISO 32, full transparency I'm an idiot and was looking for ISO 32 oil like a brand ... had to call him back ... as everyone is probably already aware on this site but that is just a rating. According the hyspin data sheet it is ISO 32 compliant

  9. #9Nige2022-04-13 14:08

    ISO 32 is a viscosity, not a standard that has to be complied with. Hyspin oil is available in 3 versions, each with a different viscosity - 32, 46, & 68. Which one of the three did you buy.?

  10. #10cpmartin19892022-04-14 13:05

    ISO 32 is the version hyspin that i purchased

  11. #11cpmartin19892022-04-14 13:34

    Finally getting back to looking through manuals on this machine. According to my IR images it appears that hose 1 and hose 2 are the ones that are getting warm quickest. Also the hissing continues until a work motion is operated, the bucket, arm, travel motors etc. Not sure if that helps but wanted to give as much info as possible.

  12. #12cpmartin19892022-04-14 15:24

    Doing some more reading I am thinking maybe the LS valve may have some containments in there causing it to not fully seat/unseat allowing full main pump pressure.

  13. #13Jokes342024-03-25 17:21

    Good evening, I would like to ask what was wrong with the komatsu pc35r-8, because I have the same problem, thank you