Hi, I have a 1978 Case 680g that I recently started up after it sat for a few years. It started right up and after working the hydraulics for a while I finally got a full range of motion on everything. However when I went to move it, I have very limited turning on the steering wheel. The steering wheel will only turn a few inches to the left and a few inches to the right before stopping. When I turn the wheel the hydraulic cylinders for steering work intermittently and slow. Sometimes I will get the tires to turn all the way to the right and then they will not want to turn back left. I am wondering why I'm not able to turn the steering wheel more than a few inches and why the steering is only working intermittently? Any help would be appreciated. Thanks
Raise the wheels off the ground with the loader and see if the steering wheel turns easier. I doubt it will. I would remove the two hoses that supply the oil to the steering cylinders. Remember which side they come off of. Put the ends of them in a bucket to catch any oil that comes out of them. Start the engine and see whether you can now turn the steering wheel. Doing that will narrow the problem to either steering cylinders and there related components or the steering valve. I hope it isn't the steering valve.
I did this and the steering wheel still only turned a little bit, but when it does turn it is engaging the steering valve because fluid was shooting out of the hoses. It feels like the steering wheel is binding somewhere. Do you have anymore ideas? Thanks
You might get lucky and the bearing in the top of steering gear shaft needs lubrication Does the tractor have an open ROPS or an enclosed cab ?
Enclosed cab
When the machine is not running I am able to turn the steering wheel more than the 1-2 inches that I can when the machine is running, but it doesn't seem like it is putting any pressure on turning the wheels. You can feel it slipping (over a gear?) every few inches I turn it.
Do you have a service manual for your 680G ? There is an extensive chapter in it for trouble shooting. Is the hydraulic tank full and is there 15 psi of air in the hydraulic tank ?
I do have the manual. The tank is full and definitely has pressure on it. When I turn the steering wheel left and right I do hear a humming noise. Do you recommend I do the pressure tests that the manual mentions?
Yes , the pressure tests are the first thing to check. Start with the main relief pressure. The procedure is carefully laid out in the service manual.
I did the pressure tests on both sides and came up with 1750 for the first one and 2200 for the second. Pressures were the same for both sides. I then wanted to check if the steering cylinders had any hydraulic fluid leak by. I turned the wheel all the way to the right, turned off the engine, pulled the hose off the closed end of the cylinder that comes from the secondary pressure relief, turned the engine back on and turned the steering wheel to the right. I got a steady flow of hydraulic fluid out of the hose that I removed. I did the same thing on the left steering cylinder, but with turning the wheel to the left and got the same results. This wouldn't mean there is steering cylinder leak by correct? So would the issue be with my secondary pressure relief since I had fluid coming out? Thanks
With the 2 hoses that supply the oil to the steering cylinders disconnected and dumping oil in a bucket can you turn the steering wheel freely and thru it's full turning range ? If it does there is a problem in a steering cylinder. Or it is remotely possible the steering mechanism is bound up.
I disconnected the supply hoses to the right and left steering cylinders and put them in a bucket. Started the engine and tried to turn the machine left and right. The steering wheel was still bound up. Do you think anything could be wrong with the secondary pressure relief based on the 2200 psi pressure reading or do you think it's in the control valve?
You have eliminated the cylinders and king pins from the problem. I would prolly check the secondary relief valve as per the manual. The procedure for checking malfunctioning components is on Page 5002-7 & 8. It is a slow tedious process for sure. Hopefully the problem isn't narrowed down to the steering control valve.
Ok. I completed the pressure test and both sides tested good at 1750, but for the second test both tested high at 2200 psi, 100 psi over the high end of the range. Is this worth being concerned over? Should I replace the secondary relief cartridge? Otherwise I was thinking I would probably try and get at the secondary relief valve and inspect both check valves.
I don't think 100 psi is a concern. I would definitely be looking at the secondary relief valve. It is the second step in the process of elimination for the problem. I would take it apart and inspect it. Then reset the pressure after reinstalling it. Provided that you don't find a problem with it.
It sounds like there isn't any pressure adjustment on the secondary pressure relief the only thing that can be done is install a new cartridge. Do you think I should do that or just inspect it first?
I think that checking the pressure that is being delivered to each steering cylinder should be checked before replacing the secondary relief valve. I know that you checked the flow the other day but the delivered pressure is extremely important to know.
Isnt that what was checked with the pressure test that gave us the 1750 and 2200?
I wasn't clear on where you took the readings. I was thinking you took them at the secondary relief valve.
The check valves on each side of the secondary relief valve should be checked to determine if they are in fact working like they should be.
Yea I took the pressure readings at the hoses that connect to the steering cylinders. So I think with those readings being good that leaves me with just the check valves for the secondary relief and if those are fine then the steering control valve?
Yes.
Alright I will try and dig into that this week. I will report back with my findings on the check valves before going any further. Thanks again for your help I really appreciate it.
I pulled both of the check valves and they are in good working order. I put them back in and still have the same problem with steering. I guess that leaves the steering control valve?
Perhaps. Someone with experience in steering systems will need to help you. I only know the basic operation of them. If it is the motor I would be looking for a known to be working used one.
I was able to pull the steering control valve and open it up. I found a piece that keeps the main shaft centered was broken off and the broken piece was stuck in one of the gears. I was able to have a machinist repair it. I reinstalled it and steering is now fully operational! I appreciate all your help with troubleshooting this situation. If you are every in Wisconsin let me know, I owe you a few beers. Thanks again!
Thanks for posting your success. I admire your stick with it attitude. It certainly paid off. Be sure to change the hydraulic filter. Unfortunately it is inside then hydraulic tank.