Hi, Can anyone teach me how to adjust the controls on my JCB 803 (2002 model) mini excavator, everything is very fast and sharp when using the joysticks. I was using a friend's Hitachi mini excavator this afternoon and the controls are much smoother and more progressive than mine, made the job much easier. I have hydraulic guages, just don't know where to plug them in. Tnanks in advance.
Good day I suggest you first make sure the servo pressure is not wrongly adjusted.
Thanks for info uffex, I'll try to work this out over the next week or so.
Good day Siganens I am not sure if you are making a fair comparison, be aware that the Hitachi machine most probably has a load sensing system where has the JCB has a fixed displacement gear wheel system. Your complaint will no doubt relate to a couple of movements most will point out, Boom raise & Arm in. If that is the case, before you do a lot of work, take a close look as to which controls and the machine specifications. It is possible to improve even the fixed displacement controls, however it is preferable to be sure what you are dealing with. Kind regards Uffex
Thanks uffex. I have had a read through the document you attached in your previous post and I need to ask another question. If I disconnect the pilot pressure inlet pipe from the RCV and connect it directly to a suitable pressure guage, would this be servo pressure that I am reading and can I adjust it if necessary by the reading on this guage. Someone has fitted a new pump in the past and maybe hasn't set servo pressures to suit, only reason I know is because it came with an old pump in a box of bits and pieces.
Good day Siganens You are correct, the line is normally referred as "P" port should be 34/5 bars. Check that the pressure holds up with low revolutions. The ports are often marked on the underside of the remote control valve. Yours may appear different from the illustration. Kind regards Uffex
Hi again uffex, I have identified the P port on the underside of the RCV, disconnected the pipe only to find I don't have a fitting to connect the hydraulic line to my hydraulic test guage. My test guage is stamped g1/4 and some my fittings fit this, but the hydraulic line looks like it might be M14/1.5. Do you know the size of these fittings, would be good to have it confirmed before ordering fittings......bit of a minefield trying to identify all the different types.
Good day Siganens Attached is the JCB information I have hope it is of help, many machines have test points pre-installed. You can measure servo pressure from the pump onwards down the circuit, it is not necessary to lift the RCV. Kind regards Uffex
Hi again, after a long delay I managed to get the required test hose for a JCB, also managed to get a service repair manual and find that the servo pressure for a JCB 803 is 25bar. Hooked up my test gauge and the pressure is 24 bar, so I would think this is not causing the jerkiness in the controls. Does anyone have any other ideas where to look, will now be a bit easier for me as I can now identify the components with my service repair manual.
Good day When you operate the control be sure that the pressure rise aqual to the movement of the lever, the pressure you have is fine .I attach a couple of pointers that may be of help.It is possible to dampen the spool movement with some one directional check valves, a method that is used from production with some makes. Kind regards Uffex