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Faunsdale, AL | ) On the attached picture, I assume the destroke valve is suppose to be on the top where the line goes to an accumalator. If not, where should it be and do you see one in the pic?
In your picture, the stroke control housing is to the right and the plug where the destroking screw goes is on the opposite corner from your perspective. The stroke control valve or the plug where it would be installed is on the left front corner of the pump. For confirmation, you should find a set screw and lock nut on the bottom end of the same passage drilled through the housing from top to bottom. That pressure control setting/valve is what the quoted text is describing tapping. The stroke control screw pushes down on this stem when you screw it in. When you screw it back out, STOP when it gets snug, it has a stop on the screw.
2) On the attached picture, where is the spring loaded valve that farmer45 mentions here:
" 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."
3) when changing the fitlers, I assume you will loose all of your hydraulic fluid as you remove the filter. Any tricks to doing it with out draining the system? i think it holds like 15 gallons
10 gallons will get you filled back up I think.
4) I need to change the pto seal out, can it be done without draining system.
That is where the shop vac technique works well. I don't like the idea of sucking a lot of air through the sump screen and resuspending the crud that was stuck on it back into the oil. Good idea for the PTO seal, bad idea in my opinion for cleaning the sump screen
5) When hooking up a gage to the scv, do you just get one hose with pioneer coupler hooked to the gage and place it in one side?
Yes. See what your max pressure is and if it holds when you release the lever. Check both sides of each SCV. That is how the pump pressure is set (once the oil is warmed up)
6) When you destroke it, do you screw it in with the engine running at 1500 rpms until you hear the pump change sound and then turn it back? How long do you pause at the sound change?
Just a few seconds or a minute or two, whatever, you want to flow some oil through the pressure control/stroke control valve and flush out any contaminants. I have seen the oil that came out of that valve look really old and cruddy, so I don't think much actually circulates through there.
7) Where is the hydraulic screen that should be checked/cleaned? Look on the lower part of the transmission for a round plug with a square socket in it. It will be on one of the lowest points of the transmission housing. Looked it up on JD parts catalog and it appears the screen is on the left side below the filters. Might be a hex socket plug, have seen a tractor or two that had that instead of a 1/2" square socket.
8) Anything else I should be aware of???
You may find that the oil is just getting thicker as the weather has cooled off some and that has something to do with the chattering. Clean everything and then you'll know. You might also have some high pressure leaks that are taking flow which is more noticable during starting. The rockshaft lifting etc is an example of a high pressure leak and frequently causes hard starting since the pump can't build up pressure and destroke. the old shake the steering wheel trick is a farmer solution to high pressure leaks. You make the leak so big that the pump can't build up so much pressure that it is really hard to turn.
Edited by ccjersey 11/13/2012 16:32
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JD4640 hyrdaulic filters/pump questions
