AC 190 hydraulic’s
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=195827
Printed Date: 06 Sep 2025 at 7:44pm
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Topic: AC 190 hydraulic’s
Posted By: AC720Man
Subject: AC 190 hydraulic’s
Date Posted: 23 Jun 2023 at 11:40am
My buddy has a early 190 diesel. Power steering and transmission/PD work great but it will only slowly lift his bush hog that has a single hose Ram. Same issue with his V-rake. The screen at the pump manifold had been removed before he bought it. He drained the hydraulic fluid and found no screen in the sump thinking it may have been updated with a screen there. Ordered a new screen, gasket, filter, and replaced with new hydraulic fluid. We also removed the spring and piston in the pump manifold to make sure it wasn’t stuck. Previous owner had added a small nut on top of the spring to increase pressure. Other than that, the piston looked fine and was not sticking. There is only 1,400 psi at the remotes instead of 2,000. Am I missing something else or is it time for a pump rebuild?
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Replies:
Posted By: 8070nc
Date Posted: 23 Jun 2023 at 12:33pm
The good Doc may chime in but the reief valve comes to my mind
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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor
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Posted By: Ky.Allis
Date Posted: 23 Jun 2023 at 1:37pm
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Remote couplers on tractor worn out?
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Posted By: AC720Man
Date Posted: 23 Jun 2023 at 2:11pm
Couplers appear to be in good shape, but that is usually the first thing I replace when hydraulic issues arise. Have not done that yet but a good suggestion. Wouldn’t think both sides would have the same issue.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: AC720Man
Date Posted: 23 Jun 2023 at 2:35pm
An update, my mistake. Bush hog is 3 pt, it will barely lift it off the ground. V-rake uses remotes, works very slowly at 2,200 rpm. I misunderstood what he was lifting. Regardless neither hydraulic system is working well.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: DrAllis
Date Posted: 23 Jun 2023 at 3:22pm
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I don't know what is available anymore, but a main relief valve seal kit ( 70255230) was always the first thing I replaced. You can swap the Traction Booster relief valve cartridge assembly with the main relief cartridge for a test, as it is set at 2100 psi. With a good main relief valve, if it wouldn't adjust to 2,200 PSI at full throttle with warm hydraulic oil, the pump rebuild was next. The same pump delivers the oil for the 3-point and the remotes. The spool with the spring is for power steering pump and has no effect on lifting power. Whenever resealing one of these relief valves, NEVER change the adjustment screw setting. If it was the correct psi before, it will be correct after resealing the relief valve.
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Posted By: ryan(IN)
Date Posted: 23 Jun 2023 at 5:15pm
70276323 Is the new seal kit number doc is taking about. Still available
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ryan
1984 8070 FWA,1979 7060,1975 7040,1971 190,1960 D-17D,1957 D-14, 196? D-19G, 1975 5040,1971? 160,1994 R62
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Posted By: AC720Man
Date Posted: 23 Jun 2023 at 7:59pm
Thanks for the replies and the part number. I will pass that along.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: AC720Man
Date Posted: 04 Jul 2023 at 3:54pm
Rebuilt the relief valve this morning and it definitely needed it. O-rings were hard and for sure were not sealing very well. Ordered the over priced kit. Surely we found the source of the issue we hoped. It helped some but no were near factory specs. Steering and power director work well but hydraulics are still below par. Gauges on the remotes verify it’s still not good. So, unless there is something else to try it sounds like a pump rebuild is next?
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: DrAllis
Date Posted: 04 Jul 2023 at 4:34pm
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A known good relief valve and poor pump pressure means a bad pump section. Section affected supplies oil for 3 point and remotes. Bad pump pressure will be better with cold oil and gets worse as oil warms up.
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Posted By: Michagman
Date Posted: 04 Jul 2023 at 5:31pm
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I just wanted to make sure you tried adjusting the relief valve pressure. Our One Ninety was bought new by my parents. After about 40 years the adjusting screw backed out and it suddenly lost the ability to lift a haybine. I recall it didn't even take one full turn to get it back to spec.
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Posted By: AC720Man
Date Posted: 04 Jul 2023 at 6:15pm
We did not change the factory setting, and did not change it after the rebuild. This tractor apparently did a lot of mowing for most of its life requiring a lot of use from the hydraulic system. Maybe a side mount or 3 pt mower of some type. That’s what Mutt was told by the previous owner. The draw bar shows virtually no wear so I would guess that was probably a correct statement. The relieve valve adjusting screw was definitely locked down tight and not loose.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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