8070 Strange Hydraulic Behavior

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   Hello Everyone,
I'm having an odd issue with the remote hydraulics on my 8070.  It seems that the system gets air in it after a period of time where the tractor has sat for a few days or so.  I've read thru the shop manual and can't really seem to uncover any info that pointed me in the right direction.  This one has me stuck as I've never really had any issues with the hydraulics on any of our 8000 series.  

Under 1500-1550 engine RPMs, the remotes always function as expected with the expected amount of pressure.  Above 1500-1550,  there is no pressure at the remotes.  If I have the tractor on an implement that uses a good bit of flow,  I can hear what sounds like air moving thru the system for a few seconds. This happens when I use the remotes for the first time and after that, the hydraulics work as expected at any RPM.  

If I'm using it on something that doesn't use much hydraulics,  say a fertilizer spreader with only a very small cylinder to disengage the web, the air never seems to clear and you have to idle the tractor down to get any flow.  

There are no visible oil leaks or anything like that,  so I am pretty well stumped on this one.  Have any of you seen this before?

Thanks!

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PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Topic: 8070 Strange Hydraulic Behavior Posted: 27 Sep 2021 at 6:33am
	Hello Everyone, I'm having an odd issue with the remote hydraulics on my 8070. It seems that the system gets air in it after a period of time where the tractor has sat for a few days or so. I've read thru the shop manual and can't really seem to uncover any info that pointed me in the right direction. This one has me stuck as I've never really had any issues with the hydraulics on any of our 8000 series. Under 1500-1550 engine RPMs, the remotes always function as expected with the expected amount of pressure. Above 1500-1550, there is no pressure at the remotes. If I have the tractor on an implement that uses a good bit of flow, I can hear what sounds like air moving thru the system for a few seconds. This happens when I use the remotes for the first time and after that, the hydraulics work as expected at any RPM. If I'm using it on something that doesn't use much hydraulics, say a fertilizer spreader with only a very small cylinder to disengage the web, the air never seems to clear and you have to idle the tractor down to get any flow. There are no visible oil leaks or anything like that, so I am pretty well stumped on this one. Have any of you seen this before? Thanks!

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DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21657	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 27 Sep 2021 at 7:02am
	Power steering never affected ?? Sounds like both hydraulic filters are NOT AGCO filters and too fine of micron.

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 27 Sep 2021 at 7:19pm
	Thanks Dr. Allis! Correct, the steering is fine. You are also correct, the filters are Baldwin. We've used these filters in our 8010 for a lot of years with no issues. I'll get some Agco brand and try that. I just rescued this tractor from the weeds this spring and after a paint job immediately changed all filters and fluids. I never used it before changing everything so I don't really know if the issue existed before I changed filters.

Ron(AB) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 27 Dec 2009 Location: Alberta Points: 959	Post Options Post Reply Quote Ron(AB) Report Post Thanks(0) Quote Reply Posted: 27 Sep 2021 at 7:37pm
	I'd say its the quick couplers...do they sweat or drip, even just a little? It doesn't take much. How many hours on the tractor? Does it have pioneer couplers or Allis?
	405, 7000, 7050, 8050, 8070, L3, 2300 & 2600 disk

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21657	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 27 Sep 2021 at 7:41pm
	If you have been using Baldwin filters in the past successfully, that probably isn't the problem. Are you absolutely sure the rear end if FULL of oil and I mean to the top sight glass on the level after sitting for a half hour ??

MACK Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 17 Nov 2009 Points: 7664	Post Options Post Reply Quote MACK Report Post Thanks(0) Quote Reply Posted: 27 Sep 2021 at 8:46pm
	I have a 7050 that does the same thing for the past 20+ years. Pumps have been out and rebuilt during that time with no change. My 7030 is ready to go to work just as soon as engine starts. I figure engine needs to warm a little before I take off anyhow. MACK

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 28 Sep 2021 at 7:14am
	Thanks very much for everyone's replies. It's truly appreciated. The couplers may weep a little. Hours on the tractor is a bit up for debate. The hour meter says ~3500 at this point, but I don't know if I 100% believe it. I don't think it's high hours because there is no wear on the drawbar, 3pt hitch or shifter gates on the powershift. So who knows, the hours meter could be correct. I just have a hard time believing that I cut a 3500 hour tractor out of the weeds. The couplers were pretty dirty and kinda rusty from sitting for years with no use I did my best to clean them up. I would assume they are the factory original. Should I replace them with AGCO or something else? They don't work as freely as I'd like anyways. This will be a good excuse to replace them. The rear end is definitely full into the top glass. I double checked this morning just to make sure and it's sat still since Saturday afternoon at this point.

8070nc Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 21 Mar 2019 Location: North Carolina Points: 580	Post Options Post Reply Quote 8070nc Report Post Thanks(1) Quote Reply Posted: 28 Sep 2021 at 9:40am
	This is one of those gut feeling things but it seems to me you could have compensator problems on the piston pump. Wouldnt take much to put a guage on the test port on the pto valve and see what is going on
	1984 80780 1957 D14 DES 300 with 25000 engine 616 tractor

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 28 Sep 2021 at 10:00am
	I can manage that for sure. Will report back with my findings. Is there any specific behavior you think I should look for? I initially thought about the compensator, but the fact that it works fine after I "get the air out" or whatever is happening has me confused.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21657	Post Options Post Reply Quote DrAllis Report Post Thanks(1) Quote Reply Posted: 28 Sep 2021 at 10:14am
	Connect a 3,000 psi gauge to the TEE fitting on the side of the PTO valve. Remove the JIC cap and connect your gauge so you can see it sitting in the seat. With engine running at half throttle or more, I like to see 600 psi stand-by pressure. When you activate a remove valve to raise position with no hoses connected to the outlets, the pressure should be 2,500 psi. Also on any 8000 series with the engine OFF activate all remote levers to the raise position. They all better lock/detent into raise. If not, change the stop bolt to allow the lever to stroke farther so it can lock into raise.

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 28 Sep 2021 at 3:06pm
	So, my dad was running the 8070 today and told me that the issue seemed to have gone away? I'm an engineer by trade and I hate it when things fix themselves. I want to know why. Here's what I know now. The FWA solenoid was leaking oil a few weeks ago and my dad discovered that the valve assembly was loose in the valve body. He just needed to tighten it and it stopped leaking. Most of our work with this tractor has been PTO and drawbar so far so we haven't used the remotes much until now. I used it on the grain drill last weekend and it made the "air clearing noises" and worked as expected after that. So, my question is, could a leaking FWA valve have been allowing air into the system? If so, I am willing to believe I cleared the air on the grain drill and now that the FWA valve isn't leaking no more air got in. But that's all speculation. Thanks!

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21657	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 28 Sep 2021 at 8:44pm
	FWA valve is supplied with oil thru the transmission pump circuit. Nothing to do with the remote hydraulics.

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 5:56am
	Well, shoot. I'll check the pressures as previously suggested.

PAFarmer Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Oct 2020 Location: Pennsylvania Points: 114	Post Options Post Reply Quote PAFarmer Report Post Thanks(0) Quote Reply Posted: 11 Oct 2021 at 9:07am
	I finally got some time to take a look a little deeper into this and follow the suggested pressure test from Dr. Allis. Standby is right around 580 pounds and remote pressure is 2600 under dead load at 1500 engine RPM. I took the engine up to 1800, and the standby pressure was around the same but 0 pressure on the remotes. I made a hose with two male pioneer fittings and put it on the middle remote. This allowed me to clear the air out of the system and at this point and the deadhead pressure at 1800 RPM was 2800. This made me check more thoroughly for leaky couplers. I did this by hooking up a hydraulic motor I had laying around from a grain auger and the bottom remote, which is the small leaver beside the seat has a pretty good drip to it when using it. The tractor has the Allis-Chalmers style couplers and they're rusty from sitting outside with no plugs for who knows how many years. Should I replace them with the newer Pioneer type or rebuild the AC ones?

Ron(AB) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 27 Dec 2009 Location: Alberta Points: 959	Post Options Post Reply Quote Ron(AB) Report Post Thanks(0) Quote Reply Posted: 11 Oct 2021 at 2:18pm
	I prefer the AC ones but it is really a matter of personal preference. It could be difficult finding good used AC ones at a wrecker. Just change one or two that are in the worst shape and see if it helps. Leaking couplers do put air into the system though. Both the male or female.
	405, 7000, 7050, 8050, 8070, L3, 2300 & 2600 disk