Hi i'm working on an older grove RT 600. It lost it's rear steering and swing function . it will swing and steer very slowly at high rpm only. when i hook up a test guage to the test port i get 400 PSI. i have checked the pressure relieve valve and the flow diverter valve and see no problem. any suggestion.
400 psi at idle or full throttle? If it's still working, but very slow at full throttle and that's your pressure reading, I'd say you have a pump problem. Knepptune posted some pictures a while back of a pump with a worn out coupler to the pump section.
First off need to say I have no knowledge of the systems on this machine, but are there other functions that the pump that works the steering and swing functions supplies. In other words say does this same pump supply the pressure and flow for something like the boom? Just trying to isolate the problem to pump, control valve or some other point. You say you have "checked the pressure relieve valve and the flow diverter valve", does this mean you have tested and found relief pressure to be within spec's or does it mean you looked at them and they "appear" to be ok?
Gear, vane, or piston pump?
Typically the groves have at least 3 separate pump sections, one section does swing, one does boom and telescope, another does winch, I'm guessing his trouble is with the section that does swing and rear steer. A lot of them, the swing section also does the outriggers. If you have a outrigger directional switch bad, it will steal all the oil, and you won't have swing until you fix the switch. They set them up so you could do multiple functions and still have steady flow.
have not had the pump apart but i believe it's a gear pump.
the manuel shows the swing and rear steer alone on the system. the outriggers work fine as does the boom. telescope and cable winch all other functions work fine . Is there a coupler between each pump section there are three sections
The coupler that wears out on those is the steer pump for the front wheels. Just curious about what year crane we're talking about. Is it a pilot pressure crane or levers coming out of the dash crane.
I don't have the year in my head o could check in the am. But I know it is lever controls
I'd make sure the selector valve isn't in line before the swing/steer control valve. If it runs straight from the pump to control it's one of three things. Weak pump, blown swivel, or weak spring in the relief valve. It should be the last section on the pump. What I've done to just test things is switch hoses from one pump section to another. Don't rev the engine to high due to the fact that each pump section has a different flow rate. But you can certainly test a pump doing that. Pump should look like this. This one is a 4-section, but yours will be very similar.
Interesting idea switching lines. I will try that. Don't like the though if a blown swivel but it was in my head. Thanks
So by looks each pump section is splined to the one in front of it. So one section could loose its splines You would still most likely have to replace two sections to repair it
It's possible but I wouldn't start there. I've never seen or heard of those pumps doing that. The front steer pumps are the ones that wear the coupler out. But that isn't related to anything other then the front wheel steering.
Working on a pump like that would be a good place to have the flow meter that we had at the shop where I worked. Disconnect the outlet for the section in question and run a hose to the flow meter and a line from meter to tank and start engine. A twist of a knob on the meter and you could adjust the pressure while watching the rate of flow. No question on if the pump was able to put out the rated flow at the rated pressure. Sad thing is that test meter is sitting in a cabinet in the back shop and no one at the quarry has any idea of what it is or how to use it! Almost makes me think I should have tossed it in the back of my truck when I retired a couple years ago. But then there are many other tools I would have wanted to salvage including a nice old metal lathe!
it runs forward to the sequenching valve and the out rigger controls the to the swivel. can't locate the year model it is a RT625 to be exact.thinking about bypassing the outriggers and see what happens .they are working fine. anyway to test the swivel short of tear down
I bypassed the pressure reducing pressure relieving valve and the the rear steer came back. I did not try the swing because the brake release comes of that valve. Been one is on order .
Sad thing is that test meter is sitting in a cabinet in the back shop and no one at the quarry has any idea of what it is or how to use it! Almost makes me think I should have tossed it in the back of my truck when I retired a couple years ago. But then there are many other tools I would have wanted to salvage including a nice old metal lathe![/QUOTE] Worst of it is Ken that one day some young manager will want the shop cleaned and tell them to throw it all out. Boston009, Glad you got it figured out. Let us know how nice it works after you change it out.
Installed new valve this afternoon. Everything is work fine now.
Thanks for the closure on the post Boston009. We all learn when the final solution is posted.