In the manual it states the following as the cold weather warm up procedure. Warming Up in Cold Weather 1. Perform the normal warm-up procedure. 2. Set the bucket cylinder at the stroke end and keep it there. Do not do this for more than 30 seconds. 3. Repeat step 2 until the bucket operating speed is normal. In step 2 it says to 'keep it there.' Does that mean against the stop and holding the stick in the curl or dump position or just against the stop with the stick in neutral position? Thanks,
It means to keep the stick in that position and run the hydraulics in "relief" but not more than 30 seconds at a time. I usually will start my Kubota and let the engine warm up a bit then raise and lower the loader arms while curling the bucket several times. I'm not saying that what your manual says is wrong it just seems like unnecessary pressure on the hydraulic system, that's just my feeling and I could be 100% wrong...
I wouldn't be worried about it
Why not? Do you think viscosity has little/no effect on the longevity hydraulics? I don't care about how soon the machine is able to work at full speed but I do care about causing any damage.
All it does is force oil over relief pressure and through the reliefs. This happens all the time during normal operations and will not harm the machine (they're called reliefs for a reason). It warms the oil by sending the oil through the small relief orifices. At some point you may need to replace the relief springs, but these are simple and an expected wear item.
I totally agree. If you don't think warming up a machine in cooler weather makes a difference, run logging equipment with hydraulic pumps at -20*F with no warm up and you'll find out soon how fast you can take out a $4,000.00 hydraulic pump.
So Bliz, Do you recommend warmup by running against the relief or what do you recommend?
Yes, if that is what the manufacturer recommends. At a minimum when it's cold, let the machine warm up at idle until the temp come up slightly. Then slowly work the loader up and down or slowly curl the bucket. On our logging crane, we would engage the pump to get the oil flowing and then slowly rotate the bucket (grapple) for about 10-15 min.s, depending on how cold it was. The idea is to warm up and equalize the hydraulic fluid temperature in the system. One of the worst things for a hydraulic pump is to hammer the pump, such as dropping the boom and stopping it quickly. The best info I ever got was from a hydraulic shop that was re-building a pump for us. These guys know what causes pumps to fail. Stop at a shop and talk to them when you get a chance. You'll learn a lot.
That's why this procedure seems so odd to me. To make a cold system run at maximum performance before temperature equalization just doesn't feel right. I'll verify it with the dealer.