I bought an old Lc80 excavator.....it works ok when it is cold....a little weak on the hydraulics, but when the oil heats up a little things move slower and has no power......only the swing seems normal.....if you jerk the levers hard it will react.....but if u ease the levers slowly it seldom moves anything.....I am thinking the pressure relief valves are bad or set to low.......I have not put a gauge on it yet.......is it possible the hyd oil is the wrong type?.......does anyone have experiance with these machines?....... I would appreciate ant help......thanks, John.
Well haven't seen one in 35 yrs. but here is some info. The machine works at 5000psi +, the pumps, one at 10.5gpm feeds the swing first and then down stream to the travel, the other pump 21gpm feeds the attachment valve and depending on the selector valve flows to the return or combines the flow to the travel valve. The first thing to check is the engine rpm at 2000 rpm and the drive belts for the pump not slipping and hyd filter service. You are only looking at around a 31 gpm system so it was not a speed demon when new. Your main valve, (attachments, boom, bucket, stick) is called the S18 and has a main relief set at around 4300 psi, the track valve is the P22, and the swing valve is the S15 with a main at 4300 psi. The tracks relief's set at 5000 psi, boom and stick 5000 psi, swing 4500 psi, bucket 5000 psi. You really need a pressure check, relief valve checked and also some of the checks valves that may be letting the oil bypass to tank rather than building pressure. The other issue is the age/wear of the 21 gpm pump itself. I will try and dig out some more info from the past, that machine is at or close to 50 yrs old.
Not sure if this is applicable to your machine but I recently bought a CL60 and it was very slow. Came to find out there is a lever behind the seat that controls the speed. It has 3 settings which must regulate hydraulic pressure as the machine is much faster with the "higher" setting.
Thanks sheepfoot.....it sounds like a check valve to me......it works part of the tim Thanks......any info you can help me with would be appreciated. ......I think it must be a check valve......it works ok some times and then nothing......it gets worse as it warmes up........is there anyplace that sells parts for this machine?..............QUOTE=sheepfoot;572784]Well haven't seen one in 35 yrs. but here is some info. The machine works at 5000psi +, the pumps, one at 10.5gpm feeds the swing first and then down stream to the travel, the other pump 21gpm feeds the attachment valve and depending on the selector valve flows to the return or combines the flow to the travel valve. The first thing to check is the engine rpm at 2000 rpm and the drive belts for the pump not slipping and hyd filter service. You are only looking at around a 31 gpm system so it was not a speed demon when new. Your main valve, (attachments, boom, bucket, stick) is called the S18 and has a main relief set at around 4300 psi, the track valve is the P22, and the swing valve is the S15 with a main at 4300 psi. The tracks relief's set at 5000 psi, boom and stick 5000 psi, swing 4500 psi, bucket 5000 psi. You really need a pressure check, relief valve checked and also some of the checks valves that may be letting the oil bypass to tank rather than building pressure. The other issue is the age/wear of the 21 gpm pump itself. I will try and dig out some more info from the past, that machine is at or close to 50 yrs old.[/QUOTE]