1970 Case 1150B blade problems

JM7331 · Sep 2, 2020

I have an 1150B and the blade will only work for about 10 - 15 minutes. I have replaced the charging pump and the main hydraulic pump. I have also drained and replaced all the hydraulic oil and all filters. This dozier has a six way blade and there are no leaks on any of the cylinders. The dozier will move forward and backwards and turn with no problems.
Does anyone have any suggestions on what is causing the blade to stop working, or what to do about it? Any help would be greatly appreciated.

Jim.ME · Sep 3, 2020

Do all functions (lift, angle, tilt) all stop in all directions at the same time? Does the blade hold a position if you don't touch the control lever, while you push, after the hydraulic control functions stop? All functions stopping could be the relief valve opening and hanging up open, one possibility. My thought is you need to do some pressure checking to pin point the problem. Did you do any diagnosis before changing the pumps? If so what did you do and what were the results that lead you to change them? Did you clean/change the suction screen/filter inside the hydraulic tank?

JM7331 · Sep 3, 2020

All blade functions stop at the same time, but it's a gradual stop. There is a noticeable slow down in blade response before stopping. Yes the metal filter/screen in the tank was cleaned. I did not do a pressure check, or flow test. My thoughts were that since this was a 1970 model dozier that the pump had enough wear that once the hydraulic fluid got hot it was thin enough to leak past the plates inside the pump, but apparently that was not the case. I have thought about the pressure relief valve and have looked for a replacement, but everywhere I have checked have told me that it is an obsolete part and is no longer available. I can't even find an aftermarket one. Do you have any idea where I could get one?

BTfromBG · Sep 3, 2020

Did you recheck the screen to see if it
was recloging?

JM7331 · Sep 3, 2020

Yes, I have actually drained and replaced the hydraulic fluid several times, and replaced all hydraulic filters several times including washing out the metal screen in the tank (it was clean and did not need to be recleaned but I did anyway since I had it out)

AJ. · Sep 5, 2020

Before replacing any more parts have a look at the main regulator valve,it could be something as simple as an o'ring on the valve body that's letting the oil bypass,or the valve not seating,the online parts list has changed and it is not as easy to see the parts as it was on the old system,I cannot find a drawing of the main valve.
AJ

1970 Case 1150B blade problems

JM7331

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Jim.ME

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JM7331

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BTfromBG

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JM7331

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AJ.

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