Been looking at JD 310SG's for sale. I like the model specs, but my heavy equip mechanic friend across the road said he'd stay away from them. Said if a hydraulic pump fails, it could cost $3,500-$4,000 to repair versus about $600 on a New Holland Backhoe. Any advice?
Welcome to HEF LogMan ! How many hours on the unit? Maybe the seller's will allow you to pull an oil sample? SE'S and SG's have been fairly reliable compared to their newer cousins, the "J" and "K". A lot depends on the kind of maintenance the machine has had. Something to try (a quicky without actually flow testing) when looking at the machine. With the seat facing front and with the engine at idle, start raising the loader boom and then turn the seat towards the rear while raising the loader. Does the loader pick up speed and start to rise faster? If not then there could be an electrical issue or a pump issue (pump runs about $2300 + labor). While this is no guarantee of pump condition or overall machine condition it will give you an idea if pump problems are starting. Good luck with your decision.
Does the SG have a piston pump?
No, the SG's (not the straight "G") has a double gear pump setup. A main pump which supplies the oil to all hydraulic functions and an auxiliary pump piggy backed to the main pump to supply extra oil to the backhoe for faster cycle times. The auxiliary pump "turns on" when the seat is placed into the backhoe position.