770 Hydraulics

Does anyone have a map of the hydraulic connections on a 770. It has an add on 2 lever loader valve, and normal stock hydraulics. There area a couple unused ports, what is their function. The return hose for the loader valve is tucked up in between the hydra. unit and firewall,,,, impossible to change that hose, without removing hydra. unit cover,,, can that return go anywhere else ?

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I was going to remove the add-on loader valve, but more fun to leave it,,, plus allows for tractor hydraulics to run other stuff,,,

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Since I replaced most of the loader hoses, will I have to bleed the cylinders, or will they clear themselves out by operating them with no load first ?

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The Oliver manual explains how to use the power beyond feature. Remove the plug on port "A" in your picture. Two inches in, install a 3/8" plug. Attach a hose from port "A" to your two stick loader valve. The return hose from the loader valve is to be plumbed to the 3/8" port in front of the oil filter.

On the left side, C is left lever up and E is left lever down. E is the drain port.
 

I think my first picture was not a very good description,,, this pic shows how the add-on valve is connected, and it works, so it must be the correct way to have it connected. I was just wondering if thee was another return port, besides the one by filter.


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To return to reservoir,,, the loader valve return connects to "drain" port on left side ??? [ Where that hose is dangling ] .
 

So, I can return the loader valve to either behind hydr. filter, or to drain port on left side. But will need that drain port connection, if I use a single hose to a dump wagon, the drain hose will need to be connected to the down lever port. So what does this port do in photo ??


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I replaced all the hoses,,, now loader is very sluggish lifting,,ok lowering,,, and bucket will dump fine, but sluggish to return. The only hose routing changes was ,,, the return line from Loader 2 lever valve, is now connected to drain fitting,,,, instead of behind the hyd. filter fitting, it worked ok before I changed hoses,,, I used Farm and Fleet Universal Hyd. Oil to replenish oil supply,,,What did I do wrong,,, is there an air bubble trapped somewhere,,, need to rev motor to get any responses,,, ugh,,,


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The top pic shows original connections to loader valve. When I installed all new hoses, I moved the return from valve to drain hose thinking the flow would be less restricted, but now loader is sluggish, will barley raise and only at high rpms. So,, there must a difference with that return connection point,, or there is a trapped air bubble,,, or ,,,, ??? what ????


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I put things back the way they were for loader valve, return from valve is now connected to port behind filter. Original hydr. seem fine, both Oliver levers will squall at idle, and pull motor down, since they are deadheading, Connected a 2 way cylinder to right side hydr. it works fine,, did not check left lever. Loader will barely raise, lowers fast,,, same with bucket,,,something is messed up,,,, I can see input and output hoses jump a little going to loader valve,, but hoses going out to lift and bucket do not move,,,,, could the loader valve have failed ?? Stressed out,, can not figure how changing hoses caused all this ??? Maybe i will just remove that loader valve, and use the original hdr. levers

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An air bubble is not the problem. Just return the oil from the loader valve back to port in front of the filter. Not sure why it would be sluggish returning to the drain port.
 

I am just baffled by this adventure,,,,, unless I a missing the obvious,,,, this thing has got me stump,,,,,will barely raise loader,,, but will lower fine,,,,worked ok before hose change out,,,next move is to remove that add-on valve and just use the Oliver levers,, but was told i had to remove a 3/8 plug in Power Beyond port to do that,,,,jeepers,, what a deal,,,
 
GOT IT GOING, WORKS GREAT !!!!!!

What a deal this has been,,,, apparently the Power Beyond, does not like the left lever port connected to tank drain,,,,, see pic below to see how I plumbed it up, and now works fine,,,,,
Thank you very much for your help,,,,,,Happy New Year !!!!


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