Hey guys I need help on my D6R dozer. In the pass 10,000 hrs on the machine we've replaced the hydraulic pump several times. We've had to slow the pump down significantly if we wanted to get more then 500 hours on it. Now with some testing I've realized the signal oil pressure fluctuates incredibly. Fluctuating rapidly from about 1,500psi to 2,700psi on blade tilt stall and 1,600psi to 3,100psi on ripper stall. Only whenever I steer it does not fluctuate at all. Can someone advise me what to check?
Welcome to HEF Donald ! CAT guys will need a serial number.
No problem. Here's the serial number 5LN01146
I'd be intrigued to know how you achieved this. Also in the cases where you have had to install a new pump as a result of a failure what actions did you take to clean out the contamination from the hydraulic system that inevitably resulted from the failure.? What brand of filters & pumps are you buying.? This must be pretty expensive for you, by my calculations a pump every 500 hours in 10,000 you have replaced 20 pumps.......!!
Sorry, more questions. And probably more to come. How many hours/year on average does the tractor operate.? Do you have an Operation & Maintenance Manual for it.? At what intervals do you change the hydraulic system oil and what brand/viscosity of oil are you using.?
Tip#1: Don't stall the hydraulics. Tip#2: Replace relief valves.
Ok let me see if i can answer your questions. It is quite expensive but as I said when we did not slow the pump down it it lasted only a short while. But we slowed most of them down some and they lasted some 2,000 hours on average. Personally I have not dealt with this before since I have only been responsible for it for a year but know from what I've heard since its a family owned machine. So I am not sure what was done to clean the system. Filters are Wix We've had a bunch of brands of pumps including Genuine Caterpillar Remanufactured Caterpillar as well as Samek. We average about a 1000 hrs a year Yes we do have the Manual and has been Rimula SAE40 most of the time though we did use HyGard and now use Rimula 15W 40. Hydraulic oil has been changed every 2000 hrs and whenever a pump failed.
Ok i guess stalling needs to be done for testing but if i get it you mean not stall unnecessarily. Ok.
I'll have to check about relief valves. I see it has one but it might have more.
What would be your recommendation for cleaning the system?
I'll post up a hydraulic schematic for you.
You're not going to like them much......... Every cylinder & component in the hydraulics & steering system has to come off, be torn down, clean and reassembled. Also every hose has to be removed, have a cleaning sponge run through it from a pneumatic sponge gun, then reinstalled. The foregoing is the "manual version" and assumes that you don't have a portable dialysis/kideny loop machine available like a dealer might have access to. The problem is that when piston pumps like the one on your D6R fail, they send shrapnel everywhere in the system. Cleaning the system to get rid of that shrapnel is not easy, is time consuming, and last of all ain't cheap. But i guess it is cheap compared to a new hydraulic pump every 500 hours or so.......... The other issue is that piston pumps are extremely intolerant of system contamination. You're currently in a Catch-22 situation IMHO.
Continuing on............ 1. What is the failure mode of the pump.? 2. Do you have access to an infra-red temperature gun.? 3. Do you have any idea what sort of temperatures the hydraulic system normally runs at.? 4. Do the high hydraulic temp & plugged filter warnings ever come on.? Do they both work.? 5. Has anyone ever cut open a hydraulic filter (that was changed during a normal PM, NOT after a pump failure) and inspected it for the presence of particles.? 6. When the oil is warm has anyone ever unscrewed the cap on top of the hydraulic tank and got a "whoosh" as the pressure in the tank releases.?
Attached is the hydraulic schematic. I'll cobble together something for the SysOp of the Hydraulic System. It'll mean combining a few files.
Things seem to have gone very quiet ...........