Case 970 Hydraulic issue

[Camojoe87]

I am having an issue with my new to me 74 case 970. When you lift the three point you have to rev the engine up to get it to lift and I don't have any hydraulic remote function. The kicker with this is that the steering, power shift, and front-loader all work perfectly. I know the hydraulic pump and PTO control valve were replaced a couple of years ago and the tractor operated fine pulling a mower last spring. Any help/ ideas would be greatly appreciated.

 

[DRussell]

I am having an issue with my new to me 74 case 970. When you lift the three point you have to rev the engine up to get it to lift and I don't have any hydraulic remote function. The kicker with this is that the steering, power shift, and front-loader all work perfectly. I know the hydraulic pump and PTO control valve were replaced a couple of years ago and the tractor operated fine pulling a mower last spring. Any help/ ideas would be greatly appreciated.

I've never worked on a 70 series, only a 30 series, but the hydraulics on them are pretty much the same. It sounds to me like your relief valve is stuck open and you aren't building pressure.

You say the front loader works. How is your front loader plumbed? Is it off of the hydraulic remotes? When you rev up and get the 3 point to raise, is there a load on the 3 point?

Get a gauge that will read 3000 psi or more and plumb it to put in one of your remotes and see how much pressure you are building on your hydraulic remotes. If there is little or no pressure on the remotes, get a flow meter and plumb it into the line coming off the pump to see if your pump is capable of building pressure. If your pump is building pressure per the flowmeter then your problem is most likely the relief valve in the hydraulic remote valve.

John Saeli has parts for it.

 

[Camojoe87]

I've never worked on a 70 series, only a 30 series, but the hydraulics on them are pretty much the same. It sounds to me like your relief valve is stuck open and you aren't building pressure.

You say the front loader works. How is your front loader plumbed? Is it off of the hydraulic remotes? When you rev up and get the 3 point to raise, is there a load on the 3 point?

Get a gauge that will read 3000 psi or more and plumb it to put in one of your remotes and see how much pressure you are building on your hydraulic remotes. If there is little or no pressure on the remotes, get a flow meter and plumb it into the line coming off the pump to see if your pump is capable of building pressure. If your pump is building pressure per the flowmeter then your problem is most likely the relief valve in the hydraulic remote valve.

John Saeli has parts for it.

My front loader is connected right after the hydraulic pump and before the filters. All that is on the 3 point when it tries to lift is a 6-foot box blade. Thanks for the help

 

[DKase]

If your loader is plumbed in before the remote valve you have eliminated the pump as the problem. Do you have a pressure relief plumbed into your loader valve with relief to sump???? If not you are playing with dynamite! Remote valve has priority over the 3 pt. Since your remotes do not work right that is where your problem is. DR has it right. You will appreciate the Case engineers with French lessons when you see what you have to do to get the relief valve out.

 

[used red MN]

Hello Camojoe, welcome to YT! I am no expert on these but have done some work to s 1070. When you say “tractor operated fine last summer pulling a mower” I will guess the mower requires remotes and they worked fine? This loader was mounted on it and connected to the hydraulics then as it is now? To be connected direct to the hydraulic pump your loader valve must be a “flow through” or power beyond valve. So the oil from the pump runs into it and then continues on to the rest of the hydraulic system as it did before the loader was on it. The valve connected in this manner has to have a relief valve and also a return for oil coming out of the back side of double acting cylinders. Both of these require at a minimum one return line to the tractors hydraulic sump. If you loader valve is connected properly and working correctly when the engine is running and the loader valves are centered there should be no flow out of that return line. So disconnect that and try it directing flow out of the valve at the connection into a clean bucket. If you have flow with the levers centered either something went wrong in the valve. Or the valve is wrong or connected incorrectly. Photos of the system and connections of the pump and loader valve would probably be helpful. I also am not 100 percent certain but I think there is a separate pump section that operates the steering, brakes and I believe the Powershift if it has one, don’t hold me to that last item.

 

[Camojoe87]

Hello Camojoe, welcome to YT! I am no expert on these but have done some work to s 1070. When you say “tractor operated fine last summer pulling a mower” I will guess the mower requires remotes and they worked fine? This loader was mounted on it and connected to the hydraulics then as it is now? To be connected direct to the hydraulic pump your loader valve must be a “flow through” or power beyond valve. So the oil from the pump runs into it and then continues on to the rest of the hydraulic system as it did before the loader was on it. The valve connected in this manner has to have a relief valve and also a return for oil coming out of the back side of double acting cylinders. Both of these require at a minimum one return line to the tractors hydraulic sump. If you loader valve is connected properly and working correctly when the engine is running and the loader valves are centered there should be no flow out of that return line. So disconnect that and try it directing flow out of the valve at the connection into a clean bucket. If you have flow with the levers centered either something went wrong in the valve. Or the valve is wrong or connected incorrectly. Photos of the system and connections of the pump and loader valve would probably be helpful. I also am not 100 percent certain but I think there is a separate pump section that operates the steering, brakes and I believe the Powershift if it has one, don’t hold me to that last item.

That is correct, it was pulling a 6-foot Kuhn disk mower with a single hydraulic fitting. Tractor was working fine until I went to unfold the mower and nothing happened. After that the 3 point has been getting gradually worse over the past year. The front loader is what I think to be a factory loader so I am guessing the joystick is plumbed correctly. From my limited experience with the hydraulics on this tractor I figured out that the loader is mounted before the right (red) hydraulic filter. From my testing I have determined I am getting flow to the remote valve and the fluid doesnt look aerated like if there was a cut O-ring at the pump pickup.

 

[Camojoe87]

If your loader is plumbed in before the remote valve you have eliminated the pump as the problem. Do you have a pressure relief plumbed into your loader valve with relief to sump???? If not you are playing with dynamite! Remote valve has priority over the 3 pt. Since your remotes do not work right that is where your problem is. DR has it right. You will appreciate the Case engineers with French lessons when you see what you have to do to get the relief valve out.

I am dreading it especially since mine has a cab on it! As far as the loader goes it has what I think to be a original loader on it so I am hoping the joystick is hooked up correctly.

 

[mEl]

Used Red has it exactly right as far as a power beyond valve being essential, if your inline loader control valve does not have a separate drain line back to sump it is incorrect. If the 2 port valve is used any backpressure comes on the back side of the valves relief and increases the relief opening pressure and could cause pump damage and the whole valve is under total system pressure when the tractor systems are used putting all the system pressure on the spool seals in a manner they were not designed for, To clear up the other thing Red was unsure of, the loader control, tractor remotes and hitch work off the big (around 15 GPM) section of the pump and the steering and brakes and reverse lockout for the powershift are supplied by the small line 8 GPM pump. A test of the pressure at the remotes is the next best thing to a system flow test, A leak anywhere in the powershift or associated circuitry will lower the amount of oil available to the hitch and remotes causes the flow divider to try to satisfy the leak and robs the hydraulics and a flow test is the best way to pinpoint problems.