630 COM and hydraulic problems

Drew970 · Jul 16, 2018

We have an early 630 diesel case o matic that has had issues since we bought it. The first problem is that the converter pressure drops when driving in direct drive, and then sometimes it will come back up to around 120 or so and goes back down. Also I have noticed that the pressure does not build back up as quickly as our 530 does after releasing the clutch pedal. With the tractor in neutral and I engage direct drive the pressure drops and then will sometimes climb back up to where it should be.
The second problem is that the rear remotes do not work very well, they are very slow to raise an implement. When we got it they didn't work, and found that the valve in the interlock was stuck and we got that freed up and moving. I had thought that maybe the pump output pressure was low and that these two problems were related but I connected a gauge and found that the pressure was okay, it was about 210 psi and the spec is 160-235. Oil and filters only have a few hours on them. Anyone have any ideas? Thinking maybe the com problem is in the control valve?

kevinthefixer · Jul 16, 2018

Control valves are usually pretty reliable. Start at the beginning, what are you using for oil? And how much of it? Sometimes you need to run the level a little high to compensate for accessories like maybe a loader. Any leaks?

mEl · Jul 16, 2018

(quoted from post at 22:29:45 07/16/18) We have an early 630 diesel case o matic that has had issues since we bought it. The first problem is that the converter pressure drops when driving in direct drive, and then sometimes it will come back up to around 120 or so and goes back down. Also I have noticed that the pressure does not build back up as quickly as our 530 does after releasing the clutch pedal. With the tractor in neutral and I engage direct drive the pressure drops and then will sometimes climb back up to where it should be.
The second problem is that the rear remotes do not work very well, they are very slow to raise an implement. When we got it they didn't work, and found that the valve in the interlock was stuck and we got that freed up and moving. I had thought that maybe the pump output pressure was low and that these two problems were related but I connected a gauge and found that the pressure was okay, it was about 210 psi and the spec is 160-235. Oil and filters only have a few hours on them. Anyone have any ideas? Thinking maybe the com problem is in the control valve?

The pressure in the 200 lb range is the torque converter working pressure and has nothing to do with loader pressure. Direct drive pressure loss is caused by a worn PTO drive shaft bushing and shaft at the torque converter rear bushing and requires a complete removal to replace the bushing and replace or repair the drive shaft.

Get a pressure gauge that reads at least 2000 LB and put a quick coupler on it and read the hydraulic pressure at the remote and post back with the result. I do not know what the hydraulic pressure is but would suspect it will be over 1000 LBS, Maybe Joe or someone who has manuals covering this or similar models will be a little more exact

Drew970 · Jul 17, 2018

The clutch pressure was within spec at around 105-110 psi, however when going off the gauge on the tractor the pressure goes below the green zone when in direct drive. I just tested the converter pressure and that was about 10 psi, the manual said it should be 30-40 psi. So it is definitely leaking internally in the com. I had tested the oil pump pressure before and that was 210 psi. I have right at 1000 psi at the remotes. So are there two pumps, one for the com and then one for the hydraulics? I don't have a loader on this tractor either.

Drew970 · Jul 17, 2018

Here are the tests that I did.

mEl · Jul 18, 2018

You are quite possibly right about wear within the com unit causing low converter pressure, however as I stated earlier Direct Drive pressure is being lost at the rear PTO shaft bushing, I have a lot of experience with those units and have replaced a lot of bushings and shafts, Case incorporated a sealing ring in later shafts and I have cut sealing ring grooves in older repaired shafts to up date them, have welded up shafts and re-turned them to bring them back to usable. The most common thing that seals the direct drive oil from leaking off and keeping the direct drive from holding is the shaft to bushing clearance. The little regulator block along side the main control valve is the TC pressure regulator and I have seen them stick but that uresults in no TC pressure.

I have dome many of those units over so if you need help along the way I'm here.

630 COM and hydraulic problems

Drew970

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kevinthefixer

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mEl

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Drew970

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Drew970

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mEl

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