# NH TC40a- lost hydraulics, replaced pump, still no hydraulics. Stumped...anyone help?



## Stephdmp (May 30, 2015)

2007 NH TC40a hydraulics issue

Went to unload off trailer, lifted bucket, caught a bit of resistance, lower back down, and have had no hydraulics since. The seal was blown, replaced it. Changed fluid and filters. Still no pressure. Checked all disconnects, replaced seals and o-rings, still no pressure. New pump. Still no pressure. Very little flow. No idea where to look next. Anyone else had this issue? Can't seem to figure it out.


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## Blackbear (Feb 24, 2015)

don't know ur tractor but had similar with mine.it has a pressure relief valve and some dirt got in it.it would bypass most pump pressure back to tank,like you nothing would work.my tractor has levers on dash with the valve body under dash and the relief valve was on it.

its like a safety thing if your pump puts out too much pressure(under load) it opens and bleeds it back to hyd tank.save from blowing a hose,ect.
I guessed where it was as it had kinda cap that screwed off.mine was adjustable.u can set the pressure to ur valve body.

btw if I remember right I could hear the fluid bypassing(flowing) when I tried to use hydraulics.took it apart cleaned it and all good.if urs is similar count the turns when u unscrew it.after u put it back together if ur hydraulics don't feel strong enough adjust it till u get it where u want it.i didn't use any guage,just guessed.


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## Stephdmp (May 30, 2015)

*Thanks*

We will see if that is it. We have had it apart and checked every where we can think.


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## BigT (Sep 15, 2014)

The relief valve is item #9 on the diverter block parts diagram. 

See also items #6 and #13 on lift cover head.


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## Stephdmp (May 30, 2015)

Thanks. We have taken it to the mechanic this morning. We are sure it is something simple at this point but can't seem to get it on our own. I guess a bought lesson will be a taught lesson.


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## Stephdmp (May 30, 2015)

Just a follow up: it pretty much blew the whole system. We had already replaced the pump but they ended up having to go through the whole thing. Costly, and stumped the mechanic in the beginning as well. 
We bought the tractor used, so it appears lack of maintenance from the previous owner was the culprit. 
Thanks for help!


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