FF01U1Q203192 Had this machine torn down for about a week to replace the engine rear main seal and the "transmission" coupler on the flywheel. First time for me on this machine, but a job I have done about twenty times before. After I bled the pumps and fired it back up I have very little power to hydraulic functions. Things move, just very slow and the boom will not lift under its own power. By that I mean, I could only get the boom off the ground by using the bucket cylinder to rotate the coupler (or the thumb cylinder) against the ground while booming up. But once the second function got past the point of having ground to push against... No more boom up. There were a few more things that I worked on while it was torn down. I know some of these are very unlikely to be related, but I will list them anyway. Engine valve cover gaskets, left pilot valve joystick spool seals, ccv breather hose, hydraulic tank suction screen, hydraulic tank return couplers (flex master expansion joint hardline compression fittings), replaced an oring on the hardline between the valve body and the oil cooler. That is the less likely list.
So, I broke a pressure sensor (#1 in the above pic) either while taking off the panel above it or while removing the muffler, either way, replaced the pressure sensor. Arrow number two is a little off, but you can see the leaking hydraulic hose center top of picture. I replaced a lot of hydraulic lines. Left side accumulator hose, pilot pump suction line, swing motor case drain, pilot pump pressure line to pilot filter, pilot filter pressure to quick coupler solenoid. Gonna post another picture with arrows
#2 is pilot pressure to quick coupler solenoid valve. #1 is pilot pressure to left pump... something.
I suggest you check the pressure of 02 ports SA and SB. You can use the T-connector to measure the pressure of SA and SB at the signal control valve or right at the regulator on the main pump.
I had that thought also, the leaky line in the first pic is one of the signal lines. Replaced the lines and tested with a Guage and the pressures are within spec and match what the monitor is telling me. So when I realized that the bad hose was one of the signal lines I stopped typing before finishing. The rest if the story is what I worked on on the control valve. Couple of orings on spool fittings. Replaced the auxiliary relief valve on the five spool section and the oring on the other relief on the top of the five spool (don't remember what function that was for but don't think it's the issue). I am pretty sure that the problem is the main relief. I had the main relief valve out to change the orings between sections. I marked all of the sections before taking it apart (so I thought that would keep me from having to make any adjustments) and it all went back the same way. I dont recall anything going wrong, but i think something did. I could pull it out and look at it but i have nothing to compare it to and my manuals seem to be pretty tight lipped about the main relief. I can't find a cross section of it or an adjustment procedure or method of testing. I piped into the two easiest circuits for me, auxiliary and bucket (iirc each is independent to one side of the control valve so that covers both pumps) and against relief only see about 300 to 400 psi. So now I am waiting for the dealer to let me know if they have it or how far away it is. Gonna go check my library to see if I overlooked a book. In the meantime, if anyone can share the main relief testing and adjusting or has a cross section view of the main relief it would be hugely appreciated.
Found the missing book. So I have the testing and adjusting info and the cross section.
Pulled the relief and tore it down again but didn't really find anything obvious. I haven't heard from the dealer yet so I thought I would ask a couple questions. Is something supposed to be here
That isn't here?
I don't recall anything there when i checked those orings. But i dont see any marks that would indicate that the spring was riding where the arrow is.
Thanks, but everything is there and I can't find anything wrong with it. The new relief fixed everything. I do have a question about setting the relief, but I will post another thread. Thanks all.