# Hydraulic relief valve bad?



## EP402x (Jan 8, 2021)

Ford 1715: when I raise the loader it is jerky all the was to full extension and makes a squealing noise while it is raising. The 3 point also is jerky when raising. The loader moves about an inch at the cylinder, stops, then moves again. I changed the fluid and filter but this did not make a difference. Is the hydraulic relief valve bad and if it is how do I fix it and where is it at? Thank you
I have no experience with hydraulics. Is the hex head at the 9 o'clock position the relief valve?


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## BigT (Sep 15, 2014)

I suspect that you are getting air into the hydraulic system. See attached hydraulic piping diagram for your tractor. 

https://www.messicks.com/nh/136477?sectionId=281296&diagramId=1007884

Areas where you could possibly suck air into your system:
Item #10 - hose splice on the suction line. This hose is old and may be deteriorated.
Item #27 - Suction o-ring.
Item #35 - Suction gasket.
Item #26 - Suction o-ring
Also your filter seal could be leaking?? Also, inspect your suction tube for minor oil wetness possibly indicating a pinhole leak. 

After you have eliminated all the above potential suction leaks, loosen the high pressure connection (Item #7) at the pump. Put a bucket under it to catch fluid. Crank the engine (do not let it start - leave the kill rod out) till your pump produces clean hydraulic fluid. Tighten the connection and see if your hydraulics are improved.


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## EP402x (Jan 8, 2021)

Super, thank you so much.
EP


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## EP402x (Jan 8, 2021)

BigT said:


> I suspect that you are getting air into the hydraulic system. See attached hydraulic piping diagram for your tractor.
> 
> https://www.messicks.com/nh/136477?sectionId=281296&diagramId=1007884
> 
> ...


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## EP402x (Jan 8, 2021)

Thanks for the help, I found a worn out O ring in the control box. $2.04 part!


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## BigT (Sep 15, 2014)

Thanx for posting back with your fix EP402x!!


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## tatedogrocks (9 mo ago)

EP402x said:


> Thanks for the help, I found a worn out O ring in the control box. $2.04 part!


If you would, which oring was it? happen to have the part number or diagram number? having similar issues, thaks


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## pogobill (Jan 31, 2012)

Welcome to the forum. See post #2, it has a link to the parts diagram that these guys were referring to. The original poster fixed his issue and has not returned in over a year, so getting a reply may be a bit difficult.
There are a few different O-rings but they aren't that pricey. If you feel that you must fix the valve box, I'd change all the O-rings anyways.


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