7080 Hyd. Problem
Printed From: Unofficial Allis
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=187229
Printed Date: 10 Aug 2025 at 4:37pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 7080 Hyd. Problem
Posted By: CrestonM
Subject: 7080 Hyd. Problem
Date Posted: 23 Mar 2022 at 3:59pm
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Since I got my 7080, the steering and remotes haven’t worked right. This was about a year ago. It’s been in an ex-Agco shop since October, and I haven’t heard any updates. I’m just curious what people’s opinions are…the steering works, but it turns really hard and you must use both hands. There’s a lot of resistance. Running the engine over half throttle helps a bit. Jacking up the front end makes no difference, and all the mechanical linkage is free. When you shut the engine off and bump the steering wheel, it turns back and forth quickly for a second or two like there’s a bunch of pressure in the system. The 3pt works, I never tried to pick anything up with it so I don’t know if it will lift a load. The remotes will extend/retract a cylinder, but it would not fold my folding disc, or even lift it off the ground. Engine RPM made no difference. I changed both hydraulic filters and the fluid. Some Teflon tape bits came out stuck on the outside of one of the old filters. All the parts for the filters are there, including the plate with the spring. Anyone out there with 7000 series experience have any ideas? This is just for conversation, like I said, the tractor is still in the shop, but no one knows what’s wrong. |
Replies:
Posted By: bigal121892
Date Posted: 23 Mar 2022 at 5:03pm
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The flow divider is stuck, and is diverting oil from the steering system and sending oil to the brakes. The spool needs to be removed, and polished. |
Posted By: DrAllis
Date Posted: 23 Mar 2022 at 5:53pm
| Connect a 3,000 psi gauge to the "tee" fitting on the side of the PTO valve. Pressure should be 400 to 600 psi engine running hydraulics at rest. Activate a remote lever and the gauge should hit 2400 to 2500 psi. If this is true the hydraulics should work fine if you have correct coupler tips on your implements. |
Posted By: MACK
Date Posted: 23 Mar 2022 at 7:59pm
| Is it a FWA or two wheel drive? MACK |
Posted By: CrestonM
Date Posted: 23 Mar 2022 at 8:50pm
| It is 2wd. |
Posted By: nickia
Date Posted: 23 Mar 2022 at 8:50pm
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my 7080 does the same |
Posted By: DrAllis
Date Posted: 23 Mar 2022 at 9:05pm
| Power steering issues and hydraulic lift issues are unrelated. Two separate systems. |
Posted By: CrestonM
Date Posted: 23 Mar 2022 at 9:07pm
| That's what I thought. Each gets its flow from a different pump, so I was wondering why both wouldn't be working. |
Posted By: DrAllis
Date Posted: 23 Mar 2022 at 9:13pm
| Until you get that 3,000 psi gauge connected, you'll never know anything about the lift system. |
Posted By: CrestonM
Date Posted: 23 Mar 2022 at 9:19pm
| I'll call the mechanic tomorrow and see what he's done, and I might suggest that. I hate to be one of "those guys" asking questions all the time and telling a mechanic how to do his job, but it's been in the shop over 5 months and no culprit has been found. I need to be getting ground worked, it will be cotton planting time in a month and a half, and I'm tractor-less. |
Posted By: AC7060IL
Date Posted: 24 Mar 2022 at 5:38am
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Creston, hope your new 7080 is up & running soon so that you can enjoy tillage with it this spring. Here’s some past AC forum posts that discuss 7000 series steering - hydraulic problems. https://www.allischalmers.com/forum/7040-steering-problem_topic99136.html" rel="nofollow - https://www.allischalmers.com/forum/7040-steering-problem_topic99136.html |
Posted By: JPG AUSTRALIA
Date Posted: 24 Mar 2022 at 7:05am
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If its been in the shop for 5 months and no problem has been found the guy obviously isnt going to fix it. He should have said its beyond my capacity and given it back. Ask any question you want its your machine. |
Posted By: MACK
Date Posted: 24 Mar 2022 at 8:23am
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Are you sure the screen is in left filter and has Agco filters? Earlier post, I was thinking 8070. MACK
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Posted By: CrestonM
Date Posted: 24 Mar 2022 at 11:28am
| Mack, that is correct. I put Agco filters in, and even pulled it back out to double check the screen was present. |
Posted By: DrAllis
Date Posted: 24 Mar 2022 at 12:09pm
| And the right hand filter had the spring/cover go in first ?? filter would be last. It cannot be backwards and function correctly. |
Posted By: CrestonM
Date Posted: 24 Mar 2022 at 12:26pm
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Yes, that is correct. When I got the tractor, it didn’t have the plate with the spring. Ordered a new one from Agco. A couple times, the steering would work fine. But just for a few seconds, then go back to requiring two hands. But very occasionally it would work and you could turn it with one finger. |
Posted By: SLee(IA)
Date Posted: 24 Mar 2022 at 12:55pm
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I bought a 7030 used in 1979. I still have the tractor. The steering would not turn when cold and would work some when warmed up. In the back of the left filter housing is a metal strap that the filter pushes against to open the door that lets the hydraulic oil into the housing. That strap was bent back so the filter could not open the door far enough to let enough oil into he filter so the pump could work. How or why it was bent i don't know. If I remember I pulled the filter housing off to get the strap straight. Been working perfect since. Steve
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Posted By: DrAllis
Date Posted: 24 Mar 2022 at 1:41pm
| If that is the problem (and it could be) the operator should hear the pumps cavitating, because they are starving for oil. This would also have an effect on the main implement pump, but again the hydraulic system would be making noises. |
Posted By: CrestonM
Date Posted: 24 Mar 2022 at 3:01pm
| Been 5 months since I looked at it, so I can’t say if that was bent or not. I never heard any pump noise, at least nothing like I hear on a lot of Deere models. We had one at a dairy I used to work at that sounded like a hammer tapping every time you used a hydraulic function. |
Posted By: FREEDGUY
Date Posted: 24 Mar 2022 at 6:59pm
That "hammer tapping"phrase brought back memories of the D15  !! I hope all gets sorted out for you sooner-than-later Creston
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Posted By: CrestonM
Date Posted: 24 Mar 2022 at 7:34pm
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My B makes a hammer tapping noise under heavy hydraulic load as well, but the hydraulics work smoothly and it’s 80 years old this year, so I haven’t thought much about it. At this rate, the “sooner” time period has already passed, i’m just hoping to get it back before fall harvest… |
Posted By: MACK
Date Posted: 24 Mar 2022 at 8:45pm
| I have also found strap bent and found one on backwards. MACK |
Posted By: CrestonM
Date Posted: 28 Mar 2022 at 1:47pm
| I talked to the mechanic, says he’s waiting on parts for his hydraulic tester. I don’t know what kind of machine it is, but the parts are back ordered. That’s the latest update |
Posted By: DrAllis
Date Posted: 28 Mar 2022 at 2:29pm
| It doesn't take a hydraulic tester (flow-rater) to remove the steering pump priority valve and make sure it isn't stuck in its bore. If it's stuck and removed and polished and the steering starts to work like it should, there's no need for a tester. |
Posted By: CrestonM
Date Posted: 28 Mar 2022 at 6:26pm
| I agree with you, Dr. What I should’ve done in the beginning was try to diagnose it myself by asking about it here. With a couple gauges and a day’s work I might could’ve fixed it. Especially if it is just a stuck priority valve. But it was at the overlapping time of wheat sowing and cotton harvest, and I just had more than I could handle at the time. So I took it to the dealer, thinking he could have it done a lot quicker than I could. I believe in five months, I could’ve fixed the hydraulics, air conditioner, cab blower, and a blown remote outlet hose behind the cab. Whenever I get it back, I will still have to fix all of that. Great. |
Posted By: Lynn Marshall
Date Posted: 28 Mar 2022 at 9:26pm
| I don't personally recall ever using a flow rater on a 7000 series. Won't say that I haven't, just don't remember. Gauges will tell you most everything you need to know. Sure sounds like a flow restriction problem to the pumps, especially the left hand filter. You seem to have two problems with two separate circuits that the common factor is that left hand filter and getting oil through it. Always possible to have two separate pump problems, but somewhat doubtful. I should also add,be sure that the sight glasses are full. They can get a brown film on them and appear to be full of oil when they are not. |
Posted By: CrestonM
Date Posted: 29 Mar 2022 at 10:35am
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I tried calling him yesterday but got no answer. You make a very good point, Lynn, about two different pumps having problems and having the left hand filter in common. I did change the fluid before I took it to the shop, and removed and cleaned the sight glasses while I was at it. |
Posted By: CrestonM
Date Posted: 30 Mar 2022 at 7:15pm
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I have an update…the mechanic called me, he hooked his flow rater up to the steering circuit, and once the oil got warmed up, it flowed about 5 gallons or something to that effect. However, when a load was applied to the steering wheel, it wouldn’t flow at all, and it built less than 1000 psi. What he’s thinking, and what makes sense to me, is since the left hand filter was missing the screen when I got it, it wasn’t opening that door in the filter housing, starving the pump of oil, and what oil did go through there wasn’t filtered. I don’t know how well the previous owner cleaned his remote hydraulic tips when he plugged them in, I don’t know how long he ran it without that screen on the filter, but the assumption now is the gear pump is probably junk. And he said he couldn’t test the piston pump until the gear pump was replaced. A rebuilt gear pump was quoted at $3000, and a new aftermarket pump was quoted at $5000. I’m not sure what to do next, I know if I put this much money into the tractor I probably won’t get that back out of it, I would have a total of about $10,000 in the tractor. I’m not sure whether I should try to find a cheaper used pump to put in, because I understand the gamble with that as well. Taking suggestions at this point. Thanks!
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Posted By: DrAllis
Date Posted: 30 Mar 2022 at 7:36pm
| Over the years, I have bought several from salvage yards fairly cheap and as-is. I always disassembled them to inspect and replaced the transmission pump shaft seal and put them into service. Sometimes took two pump assemblies to make one that was good enough to use. But remember, my labor is free. The newer the pump is, the more improvements it has in it. Several changes occurred from 1973 until the last 1981 models. |
Posted By: CrestonM
Date Posted: 30 Mar 2022 at 7:43pm
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Would a pump out of a 7020 work in this 1975 7080? There is a somewhat rough 7020 coming up at auction on Saturday, but the hydraulics seem to function as they should. I thought I might buy the tractor, take the pumps out of it, and sell or part out the rest. It has nearly new near rubber on the back, which I don’t need, but that might could help me recoup some of my cost.
Edit: I’ll add that while the hydraulics in the 7020 do work, they make a whining noise that I’ve never heard in any other tractor. It gets louder as I turn the wheel.
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Posted By: DrAllis
Date Posted: 30 Mar 2022 at 9:44pm
| 7020 pumps fit. Hydraulic lines touching the cab anywhere make noise. |
Posted By: GM Guy
Date Posted: 09 Apr 2022 at 1:02pm
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Mike's equipment, Buhler KS should have a pump on hand. Would be a shame to kill a running tractor when there is already plenty in salvage. Still try to buy the 7020 if cheap, but fix it up, handy to have 2 tractors. ------------- Gleaner: the properly engineered and built combine. If you need parts for your Gleaner, we are parting out A's through L2's, so we may be able to help. |
Posted By: CrestonM
Date Posted: 10 Apr 2022 at 8:37am
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I thought the same thing. I’m not going to kill it. I found a guy who had a used pump and he’d warranty it, so I’ve got that on the way. 7020 sold for $4,000 so I didn’t bring it home. There was a really sharp 7045 as well and it brought $10,000. |
Posted By: CrestonM
Date Posted: 04 May 2022 at 8:08am
| I received a call, and there’s been improvement. The used pump assembly I got (all 3 pumps) is installed and the steering is back to working. He said once you bump the throttle just above idle it steers well, still takes some effort at the lowest idle speed. Supposed to check the rear remote pressures next and see what we have there, but it looks like we’re on the way to having it buttoned up. |