Hello again I have a problem with my Hitachi Ex200-2 I can't regulate the pilot relief valve. I remove and clean the valve but their seem to a problem somewhere. This is how it operates when the excavator is started after installing the valve the pressure is at 0 psi. Then while turning the valve to increase pressure nothing happens only when the valve is almost in it jumps to 300 psi and that's it the only way you can get the pressure to return to 0psi is to shut the machine of and turn the valve
Good day Our experience with servo pressure differs a little from your thread however I attch a couple of documents that may help.The small gear pump can be easiliy damaged by contamination so please take care to save the bucks. Kind regards Uffex
Hello Uffex I was trying to see if the pilot valve bank may be malfunctioning in some other area than the relief valve. so here is what I did and what I notice. Removing all other lines from the pilot valve leaving only the supply and return lines then started the machine, what I notice were hydraulic fluid was coming out of all ports for example bucket, boom and swing. My question is should that be the case or should their only be fluid in the return line while the machine is in neutral. Here are some information on my system
Good day Those lines need to be open to drain the pressure from the main valve, I suggest you plug the delivery line from the pilot pump and check to regulate the pressure - be sure that the relief has been backed off before doining this. Making this check will tell you if the issue is at the relief valve or down stream. Kind regards Uffex
Hey Uffex when i mentioned that i blocked all lines leaving the supply from the pilot pump and the drain to the tank open, i am asking shouldn't I be able to regulate the pilot pressure by turning the relief valve. I will look into what you suggest and let you know my finding.
Good day D Boy When you test the pilot pressure providing the control lock out is open (Hitachi term pilot shut off) and you measure the pilot pressure and you have none means that you have only two possibilities according the schematic we are working from 1/ the pilot pump is worn out or 2/ the relief valve has a fault. Please note we cannot be sure we are working from the correct schematic for your machine, if you have that schematic please post this it will enable us to be more sure. Kind regards Uffex
Hey Uffex what up hope all is well with you. All mt test so far is done while the machine is in neutral I am trying to set the pilot pressure to 700 to 711 psi as stated in the manual but cant achieve that. Here is the pilot hydraulic circuit in neutral.
Good day I suggest you remove the pilot filter cut it apart you are looking for aluminium deposits that will signify pump failure if not take the relief valve out and inspect it for damage or parts lodging it open. Kind regards Uffex
Hey man good day to you, I have already removed and inspect the pilot filter which was Ok and still installed new one together with a refurbish hydraulic pump with all new parts in that area in that area I had for backup. and still got the same result. The machine does all function but here are the noticeable problems 1. Unstable noise from the engine, up and down tone. To me, maybe cause by a change in pressure. Now when the electrical for the two solenoids are unplug the engine noise becomes stable. 2. Tracking issue, while doing so it will just suddenly abruptly stop. to try and get it to move again you carefully have to pull on the levers, it may or may not move and if it does its only for a short distance before it abruptly stop again. 3. low and non adjustable pilot pressure. Hope this explained a little further.
Good day D boy I have no solution that adds up to your circumstances may I suggest you focus on getting the pilot pressure correct if the pump is good it must be the relief valveproviding that all solenoids are without power. Kind regards uffex
May I ask exactly where you placed (pictures?) your gauge to check pilot pressure?
I installed the gauge as the manual stated in that area under the pilot pump.
Don't have any pictures in that area and is in the office presently so here is some information from my service manual.
Hi guys gerry here I have an ex 200-2 with slow hydraulics, it has a electric to hydraulic conversion done . is there any way i can turn up the hydraulic pump
Hi Is there any documents to FH 150 LC3 -model hydraulic system adjustment? I change main pump but hydraulic system not work perfect. Probably pilot pressure shoud adjust.