70 diesel power trol problems

[David Hunt]

I have a 70 diesel that im having problems with the power trol. I have good pressure on one hose but not on the other.i used it to plow with this spring it picked the plow up good but it sure was slow going down. i tried to adjust the two set screws to see if anything changed but nothing did. could i have a stuck valve??

 

[F-I-T]

More info needed David.

1) Did it ever work right?

2) Do the hoses come out of the rear plug holes, or from the side pipe plugs?

3) Does your 70 use a selector valve in the top hole?

Remember, the two "set" screws, metering and throttle valves, act very differently and are meant to be adjusted independently.

4) Do you have an operators manual?

 

[David Hunt]

Frank, this tractor has been in our family for 40 yrs but it has been parked for the past 15 yrs. I pretty sure it used to work right. this tractor has hoses coming from the side plugs. im not sure about a selector valve. i have a manual but its not a john deere manual.think its a chilton??

 

[F-I-T]

You ought to get a copy of the correct operator's manual, as it covers the adjustments that you may need to make, as well as how the selector valve is used.

Can you disconnect the hoses from their quick couplers and get the rockshaft to work? This can rule out Powr-Trol problems and point towards adjustments that need to be made. Remember, it only has pressure up and gravity down on the rockshaft, so to cycle it, you might have to pull down on it with a large wrench when you attempt to lower it.

 

[David Hunt]

i ordered power trol book today. almost acts like its adjusted to work on a one way cylinder.

 

[Mike M]

When hooked into the side of the power-trol box you will only have pressure on one hose and gravity down.
To have pressure both ways put the hyd. hose tips in the rear instead of the rockshaft plugs.

 

[F-I-T]

Is that true if you are using the selector valve? It sure doesn't seem that way on my 70D. Mine will lift the wheels up off the ground on a pull-type disk.

 

[David Hunt]

i see no selector valve on my tractor. what does it look like?

 

[F-I-T]

Do you have the parts catalog for your 70D? It's available for free download from jdparts,com. You really need to get it. The selector valve is #1 in the picture. You can identify it by the false cap that you unscrew to access the valve stem.

 

[Mike M]

I'm not sure about that selector valve ? I have one but never messed with it.
Does the rockshaft get it's oil from the top port or the bottom port ? I thought the selector was to block the oil from going to the rockshaft in the top port ? and the bottom was open to freely return at either setting ? I may be wrong. I don't have my hyd. service manual here handy to look in as it should show the oil flow.
I had a model 50 with a #45 loader and hooked it up several ways and ended up just putting elbows in the right side holes and hooking the hoses in there. That is how the owners manual recommended it too. It lowered better without the down pressure I got when going out the back.

 

[David Hunt]

Ok yes i do have these plugs on my tractor. i had them both out yesterday.

 

[F-I-T]

But look at them CAREFULLY. The AA 5724 R Selector plug is different than a standard rockshaft plug. It has an extra seam about an inch from the top where a protective cap screws on. You remove the cap, sealed with an o-ring, to access the inner stem. You can then turn the stem in until it seats and this allows for full cylinder operation. You can also set it for rockshaft operation by disconnecting the cylinder, and turning the inner stem outward until the inside end of the knurled section lines up with the outer end of the selector valve body, then replace the cap.

 

[David Hunt]

Ok i will look at this better today and see what it is set at. i went to jdparts.com but couldnt find where to download anything for a 70 diesel. what am i doing wrong?

 

[buickanddeere]

We just have the plugs on the back of the tractor's Power-Trol with the Pioneer quick couplers threaded on. Pressure up and down.
Never tried the side fittings in 54 years.

 

[David Hunt]

These have been hooked in the side for 40 some odd years and we have never had problems with them.... well until now. im doubtfull its "just" an adjustment, never works that way for me!!! but you never know.

 

[F-I-T]

Now it's time for you to get familiar with the search function on this board. There is ton of previously posted information out there, including how to go to jdparts.com and download a pre-1961 manual.

Here is a link to a previous post. Let me know if you don;t get it figured out.
How to download parts catalogs

 

[David Hunt]

Once again... a thousand thank you's Frank you help me figure out the problem. I pulled the plug out and screwed in the valve and my hydraulics now work. thank you again.

 

[F-I-T]

Ta-Dah!!!!!!

Good deal.

 

[David Hunt]

It's amazing!! Neither me or my Dad could remember moving that valve. just goes to show what time will do..... thank you again!!

 

[F-I-T]

Yeah, that's one of those, "Well, Son-of-a-gun!" moments.

Say, if you ever have the opportunity to have that tractor operate something like a wheel disk, where the wheels could be lifted off of the ground indicating that there is pressure up AND pressure down when using this configuration, post that back. It might help reduce the confusion for the next guy.

 

[David Hunt]

It definetly has pressure both ways now. i put it on my round baler and it moves the twine tie arm both ways now.opens the rear door(heavy) when i switch the hoses around either way. i have a new problem tho. i now have a bad leak at the quick couplers that i didnt have before. when i moved the other set screwws could i have cranked the pressure to high?

 

[F-I-T]

No. You can only increase the pressure by adding shims under the relief valve spring. The two screws under the caps are the metering screw and throttle screw. The metering screw controls the rate of rise in the slow up position and the throttle valve screw controls the rate of fast drop.

I suspect that you have a bad o-ring in the quick coupler and it has probably been bad doe some time. Now that you have pressure in both directions, it has revealed itself as bad.

 

[Mike M]

Frank; I looked in the hyd. equip. service manual. Very well illustrated too.

It does appear that the rockshaft gets it's oil from the bottom port. So it looks like the top port with a selector valve in place will open or close a return path which should allow two way operation as you described.

Now the next question is I think if one has a 3 pt. attached on the rockshaft it will go up and down along with the cylinder depending on which has the lighter load and if you hold the handle longer then when it kicks off. On my 50 the 3pt. would rise before the loader because it was lighter,then the loader would go up and down fine and all the while the 3pt stayed up unless you held the lever back extra long when lowered then the 3pt. would drop.

 

[David Hunt]

i changed the o- rings and they still leak but they have been on there for 40 + years so im going to replace them and see if that helps . thanks for all the help Dave

 

[F-I-T]

If they are Pioneer style couplers, they are relatively cheap, so that is probably the best way. Could have a pitted check.

 

[F-I-T]

Mike:

Yes, I believe that is the way it would work. I have an 801 hitch on my 70D, and I run my 45W loader with hydraulic bucket from the Powr-Trol side ports using a selector valve. I just let the lever kicked forward and the fluid flows through the open center twin spool valve, so fluid is always flowing. Once the three point hitch raises, it stays put, and since I always push the lever forward for loader operation, it stays raised. The seal/piston is tight and right, so there is no sink in the Powr-Trol or rockshaft, so you really do not ever notice a thing. It's pretty handy, but now that I have two other hydrostatic tractors with loaders, the 45W has not seen use in several years. I need to sell that one one of these days.

 

[David Hunt]

They are pioneer, i changed them today and its up and going now. thanks again... hope this thread can help someone someday.planted corn today with th 70 no leak or drifting down so im very happy!!

 

[F-I-T]

Super Dave. Good luck on the corn crop.