Case 1070

Hello, recently brother was cutting hay with our 1070 and he said he pushed in the clutch, and when he let the clutch out the tractor didnt move. he pushedand released the cluth again and tractor took off. he said it did it again a while later. i checked it over and noticed that when the tractor is at an idle and pushing in the clutch pedal. the tractor does not surge like normal. you rev the tractor up 400-500 RPMS and the tractor will surge when pedal is pushed and released, i drove the tractorback to my shop and when turning and dead heading the power steering pump, the tractor stopped. i hooked a gauge to the lube porton top of trans. at idle i got 0 psi, rev up and get 45psi or so in P/S 1 and 3 for about 35 psi in P/S 2. i put a gauge in the hydraulic coupler and checked pressure, at idle i got 2200 psi. when at idle and revving engine up slow, can hear a click from trans control housing area and then clutch pedal will surge engine with clutch pedal is pushed down. wondering on some ideas to check! Thanks for you time! Greg

i just replaced the hydraulic pump, filters and oil.ran tractor and it is still acting the same. which sucks. not sure what to check nexted. but on the plus side the steering is better!! any suggestions would be awesome

I would pull the pressure regulator spool (lube press) and make sure it is free to bottom out it the valve body and you would see if the spring is OK. The regulator spool does not have threads in the end like the pilot spools making it difficult to check with the valve body on the tractor. Does the steering work well with the oil warmed up and engine idling? Not very likely but is always possible to have a defective new pump. Also I will have to check in the manual but I think the cold oil relief valve protects this circuit, perhaps that is leaking. Rod.

(quoted from post at 00:09:30 07/25/17) I would pull the pressure regulator spool (lube press) and make sure it is free to bottom out it the valve body and you would see if the spring is OK. The regulator spool does not have threads in the end like the pilot spools making it difficult to check with the valve body on the tractor. Does the steering work well with the oil warmed up and engine idling? Not very likely but is always possible to have a defective new pump. Also I will have to check in the manual but I think the cold oil relief valve protects this circuit, perhaps that is leaking. Rod.

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My bets are on a failing 8 gal. pump section, the fact that the steering will cause the tractor to stop indicates the return oil that supplies the reverse lockout is not there at cramped steering, and the reverse lockout spool is returning to neutral causing loss of drive.

The snap you hear is the reverse lockout spool engaging which then directs the flow to the proper clutches.

If possible I would do a flow test on the 8 gallon side of the hydraulic pump before I started chasing valving.

The whole power shift operation depends on the lube circuits proper operation and the 0 psi on the lube circuit at low throttle is typical of a weak pump (8) gpm steering and brake pump, I could be wrong but that problem is to typical for me to overlook,

mEl, thanks for replying, what are some issues that would possibly cause the low oil pressure on the 8 gpm pump? i have not ran tractor long
enough yet after replacing the pumpto see if the steering will cut out the power shift. i might try it cold when i can get out into the shop.
i know the pump did help the steering, it is nice and smooth now, where before it was jumpy at an idle.

(quoted from post at 17:40:34 07/25/17) mEl, thanks for replying, what are some issues that would possibly cause the low oil pressure on the 8 gpm pump? i have not ran tractor long
enough yet after replacing the pumpto see if the steering will cut out the power shift. i might try it cold when i can get out into the shop.
i know the pump did help the steering, it is nice and smooth now, where before it was jumpy at an idle.

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I would take a look at lube pressure while steering and at steering lock, the lube pressure is essential for reverse lockout spool operation which is tied to total rps 34 function. as before 75 lbs lube is norm, you are well below that and that points to a supply problem or regulation, you could look at the lube pressure regulator as 1370 told you but in my opinion the problem is centered around the low lube pressure and its effect on the reverse lockout which you hear snap when the system starts to work.

Rob, I believe the cold oil relief is in the 210 regulated supply channel in the high GPM flow channel of the flo divider and not in a place where it would affect steering flow (8) gpm side. Have been thinking about this and am convinced lube pressure is at fault, just finding out why. :?:

ok,i will check the lube pressures after work tomorrow! i wish i had a good service manual. all i got is the i&t manual. wish i could get a
hydraulic schematic for the systems. will update once checked.

Do you have a way to test pump flow to eliminate it as a cause before moving on. Not vary likely at fault, but would help in getting you headed in the right direction. Rod.

I was convinced I had a bad pump on my 970. Swapped pumps with my 1175 which I thought was a bit weak, but still doing better than the 970. Just as a test before dropping 1k on a new one. After the swap, both tractors have much better hydraulics. Even though there was no apparent damage on either o-ring, I am convinced both suction side o-rings were leaking and allowing air past. Both tractors had some foam in the sight glasses prior to the swap. Neither do now.
I believe you said you recently replaced your pump? As easy as it is to do, I'd pull it, buy a new o- ring, and re- install the pump. I have ran in to this twice now on 70 series Cases.

well i believe i got it figured out, i was doing some pressure testing and with a gauge in the LUBE port, at idle i got 17 psi. looking in the book it shows to shim if too low. first i checked clutch pack pressure and that was 195 psi, i took apart the pressure regulator on the control housing. there was no shims. i removed the spool. looked fine, found a washer that was the correct thickness for the pressure i needed to bump it up. ran tractor. got 65 psi. on the high side of spec. i removed and ground the washer down. installed and ran again. still 65 psi. i decided to remove the washer. ran and got 55 psi. looks like the pressure regulator spool was sticking. works fine now!!! going to try it out baling some straw thsi week!!

Good to hear, hope all continues to operate well, Rod.