My 310SG has a sight tube that indicates the cold oil range. I don't see anything in it, but the hydraulics seem ok. Should I add some oil?
Yes it is supposed to between the marks when cold.
Also of note, that is checked with the backhoe on a level surface, with the boom and stabilizers in transport position, front bucket lowered to the ground.
Why do you think the manufacturer put the sticker there in the first place, for decoration..?
This is my first expensive backhoe. My Ford 4500 had a dip stick for the hydraulics. Didn't seem to matter if it was on the stick or not. So yeah, it practically was decoration. I just don't want to overfill it, and since the hydraulics are working, I wasn't sure. The next question is, how level of a surface do I need? My garage is about the only thing dead level, and it has an 8' door. Driveway has a slight cant to it.
Eyeball level is good enough
Just get it relatively level and get some of the correct HIGH GRADE fluid in that sight glass, it will do no good to the machine or you if you run it with low fluid. You could also level it up with the stabilizers.....
A very good point about using the correct fluid. However based on post #3 above, don't level it using the stabilizers because they are supposed to be in the raised position when you check the oil level. Doing it with them down will result in an incorrect reading in the sight glass. Here's a suggestion. Take the fill cap off the tank and use a dipstick down inside to find the level of the oil. Compare that to the level of the sight glass. I have seen cases before of sight glass fittings getting plugged before so that even though there was an adequate amount of oil in the tank it just didn't show in the sight glass.
Great point Nige, I really wasn't thinking when I mentioned using the stabilizers to level it up and the level of the hydraulic oil…
my 555a ford backhoe manual says close all cylinders (rod in) to check level, I have wondered why would it make a differents, all cylinders are to way action. I would like to hear others options LOL
Simple. Generally one side of the cylinder has the rod in it. So for every inch/foot/whatever that the piston moves, the quantity of oil leaving one end cannot be the same as the quantity entering the other end. Basic physics. In the example below if the cylinder is extending it will require a larger quantity of oil to enter the LH port than the quantity that will be leaving the RH port. That's why hydraulic control valves are often a lot more complicated that one would imagine they need to be, to cope with different quantities of fluid moving in the supply and return side of a single cylinder.
Thanks. Good point on the potential for plugged fittings. I'll try to pick up some fluid at JD or Napa tomorrow. Hopefully they haven't shut down.
Great explanation! I never thought of it like that. Got me thinking, dangerous, I know! Changed 8 hoses yesterday on the 580SL including the swing cylinder lines. With the swing hoses transferring fluid directly to the opposite end of the other cylinder, how does it account for the difference in fluid volume? Is that what the 'cushion' at the end of the swing is doing?
The explanation above only works for a single cylinder in a circuit, not multiple ones. If two cylinders work "back to back" such as steering where one cylinder moves in the "opposite" direction to the other, then the sum of the oil flow entering and leaving the two cylinders will be to all intents and purposes equal.
Double post.