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New Holland 8770 Hydraulic Remote Rebuild Process
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tim4870
Posted 3/27/2014 11:08 (#3779621)
Subject: New Holland 8770 Hydraulic Remote Rebuild Process


Southern MN

Hydraulics on the 70 series New Hollands, based on posting to this newsgroup, require rebuilding when they start under-performing. I'm at that point. The two problems I'm trying to solve are:
1. High pitched squeal when remote is left in the raise position when operating my sprayer boom level controller.
2. Lack of power and/or flow to fold up my sprayer booms or the wings on my ridge till cultivator.

I have the service manual and plan on tearing apart the hydraulic remotes and replacing missing/worn o-rings as needed. Is there more to it than just o-rings? Before I tear into, I'm wondering how I order new o-rings when I don't see them on the parts listings. Is there a kit with a part number?

As far as the high pitched squeal, I did find a small note regarding it occurring if the remote is held in the raise/lower position, but I'm not doing that.  I attached a picture of that note, and one of the hydraulic schematic.

I am basing my need and ability to tackle this issue based on a former post by MJS:

MJS - 1/19/2013 19:32

Check that the o rings are not gone on the primary and secondary shuttle valves in the remote valves,if they are gone it will reduce the hydraulic flow dramatically.

One of them is under the detent cap and has two o rings,the other is behind the valve stack with one o ring.The one behind can be accessed without removing the valves but you might need someone with small hands,just be carefull though as there is a ball in there,the valves are angled forward so it shouldn't, fall out.

There is also one under the left solenoid valve cover on the 3pt linkage valve and on the back of it.

The valves are recessed and take an Allen key,The o rings are a white high temp. Type. The later models have a backing ring on the o ring and should last longer,the early models don't .

I just done mine and there wasn't one of the 12 o rings left,unfortunately I had already gone through the process of converting my air seeder to a PTO pump.






(HydraulicNoise.GIF)



(HydraulicsRaisePosition.GIF)



Attachments
----------------
Attachments HydraulicNoise.GIF (5KB - 553 downloads)
Attachments HydraulicsRaisePosition.GIF (46KB - 562 downloads)
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scott nelsen
Posted 3/27/2014 12:19 (#3779762 - in reply to #3779621)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


Leeds, North Dakota
Tim, IF levers are in neutral, not sticking, I think you have a issue with standbye pressure valve, possibly sticking making pump being stroked, three remotes or four? mega flow? # 13 is a load check, as far as break down for seal #'s need to look at valve break down, there are a lot of orings in valve body. You need to print off breakdown, keep orings separate, there are shims between valve slices, also if its mega flow there is a disc, that needs to be installed correctly, # 3 slice I think, tell me more, I have worked on a few of these ladies, valve stack is heavy, give me a call, I will look up #'s for you, Scott.
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tim4870
Posted 3/27/2014 13:48 (#3779948 - in reply to #3779762)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


Southern MN
Thanks Scott for the time and help on this issue.

I have found the parts breakdown of the hydraulic remotes now. I use this website to lookup parts: http://partstore.agriculture.newholland.com/us/parts-search.html The reason I didn't see the parts breakdown is because I didn't see that there was a "page 2" of diagrams.

Had I used http://www.messicks.com/NewHollandParts.aspx, I wouldn't have had to page down, its all right there in one list of diagrams.
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deere6810
Posted 3/27/2014 14:04 (#3779979 - in reply to #3779621)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


might try pricing buhler parts, heard they can be cheaper sometimes. Have any trouble with your 3pt drifting down or you implement on the hoses drifting up or down?
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jskooy
Posted 3/27/2014 14:22 (#3780013 - in reply to #3779621)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


mount vernon, washington
I've rebuilt my 8770 three time now (tractor has 15,500 hours), I just order every o-ring in the stack and take everything apart. This will take care of the leaks and performance problems with the remotes.
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tim4870
Posted 3/27/2014 15:06 (#3780065 - in reply to #3780013)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


Southern MN
deere6810 - My 3pt hitch works as it should. Plenty of lifting power and no settling.

jskooy - When you rebuild it, what do you normally find when you take it apart? Are the o-rings just a little worn, torn, or missing?
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scott nelsen
Posted 3/27/2014 16:32 (#3780197 - in reply to #3780065)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


Leeds, North Dakota
Its very tedious, need to blow all passages out, yes, detoriate , Scott.
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jskooy
Posted 3/27/2014 21:45 (#3781086 - in reply to #3780065)
Subject: RE: New Holland 8770 Hydraulic Remote Rebuild Process


mount vernon, washington
Just wore out. Leaks between valves, flow control knobs.
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