Faunsdale, AL | farmer45 - 10/1/2011 20:01
I have a 4240 that has lost hyd power a couple of times. I'm not an old JD man so I don't know if a 4430 would be the same or not. My tractor isn't home now so I can't look at it to tell you where things are for sure. On the top of the front pump there are two plugs. I think they are on the left side. I think that under the smaller one there is a valve that is spring loaded from the bottom. With the plug out I droped a punch in the hole and tapped on it gently, Don't hit it so hard that you damage it. There must have been something that caused the valve to stick and after I tapped on it it worked fine. After a couple of years it did it again and I did the same thing and it is still working fine.There isn't anything under the plug to jump out and get lost.
That should be the stroke control valve. It responds to pressure built up in the outflow of the pump. As long as the pressure there is below the setting, it should allow the pump to go "into stroke". Once the pressure builds up, it destrokes the pump by keeping pressure on the internal end (next to the cam) of the cylinders so that the pistons do not return once they are pushed out by the cam.
they do occasionally get some crud in them. It helps to have a manual destroking screw on the pump. Usually destroke it a couple times and it will clear out. Seems that there isn't much oil circulation through the valve housing and stuff accumulates in there. I remember taking one apart that had nasty old oil in it, but the oil in the system was clean. |
4430 hydraulic system troubleshooting
