4640 Main Hydraulic Pump

I have a 1979 4640 that I use for various tasks which includes planting. I have a 12 row model 3200 Kinze planter equipped with an orbit motor driven centrifugal pump for liquid starter fertilizer and I have the choice of either using a hydraulic variable rate population drive or the factory ground driven chain drive, which is what I have been using simply because the hydraulic output on the 4640, I feel, has never been all that great. It raises and lowers the planter and hydraulic markers slower than what I would expect it to do, even when I am not using the liquid starter when planting soybeans. That pump does not seem to take a lot of hydraulic oil flow to operate it. Here are the figures when the hydraulic system was last checked when the tractor was in for some major repair work 3 years ago. 18 gpm at 1000 psi and 12 gpm at 2000 psi. Standby pressure was at 2000 psi and was turned up to 2300 psi.

My question has 2 parts. Aren't these volumes cited too low? I seem to recall seeing something about rated hydraulic flow on a 4640 being around 20 gpm, but I do not recall any more information on that. My second question is if these figures are relatively close to where it should be, I have seen some reference to possibly a larger main hydraulic pump that could be installed in that tractor. Is that something that could be done? Pros and cons to this?

In a closing thought. The figures I have seen on the hydraulic flow demands for the centrifugal pump to be around 2 or 3 gpm, and each of the two variable rate hydraulic drive motors being 2 to 5 gpm. If I want to use the full hydraulic capabilities of this planter, would I simply be best off purchasing a pto driven hydraulic power unit to operate these devices and leave the rest of them on the tractor's hydraulic system?

I am struggling with this issue because I tend to believe the main hydraulic pump is not putting out what it should.
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The 4640 was equipped with either the stock 50 cm3 pump rated at 30gpm at redline or the optional 65 cm3 pump rated for 40gpm at redline. Both pumps are single bank 2000 series units.

When the oil returns from the planter. Where and how is it ported back into the tractor?
Where and what is the connection from the tractor to supply the planter?
There are two oil filters and a screen, their condition?
 
Its close but somwhat low. If you were using it for anything else but planting you wouldn't notice. The fix for this symptom (because many people have had this issue as a 4640 is a capable machine but posses inefficient gpm to run a modern planter) is to use the pump c or a 4640 or 4840 with hyd FWA. This pump is 26 gpm. There is no down side other than the cost as it is a direct bolt on swap but you will notice a pretty large difference in response time.
 

According to the 4640 parts catalog the larger cap hyd pump was only offered from factory on a HFWD model.
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Yes those figures are about right for a "3 inch" pump, and as Jim stated you can install a 4' pump to up your flow. but it will cost about $1600 or so for the pump the the add on hydraulic pump won't work out well. We are pulling a Deere air drill with a 4960 and last year were struggling with enough air pressure to move a larger bean seed, I went with a power beyond block and straight JIC fittings ( deleting the couplers) and gained enough extra flow to make it work. We went with ground driven finger pick up units on the last couple Deere planters, feeling the consistency of that system made a better stand, this can be argued in both directions but it's what works good for us
 
Why not add a PTO pump for some of the functions and take the load off your main pump? Odds are it would be cheaper as well. Mike
 
The 4640 was equipped with either the stock 50 cm3 pump rated at 30gpm at redline or the optional 65 cm3 pump rated for 40gpm at redline. Both pumps are single bank 2000 series units.

When the oil returns from the planter. Where and how is it ported back into the tractor? Currently NOT using the hydraulic drive for the population, so nothing has been altered. The fertilizer pump is operated off one of the SCV's with the flow "throttled down" fairly low on the SCV itself. I have the flow set to the point where I can run up to 10 gallons of 10-34-0 per acre, but only run 5 to 7.

Where and what is the connection from the tractor to supply the planter? As noted prior, nothing has been altered yet. If I am reading Tim's response correctly, it would probably be wise to install a Power Beyond Block and reduce any restrictions with JIC couplers?

There are two oil filters and a screen, their condition? Don't have the tractor sitting in a convenient location, and I cannot recall for sure, but with its Quad Range, isn't it just one filter? Changed filters on every tractor last spring and my recollection on doing that is not the greatest at this point in time. We will perform a total change out of hydraulic fluids and filter(s) before we hit the field in the spring AND pull the screen, too. There are only about 350 hours since major work was done in the rear end a couple years ago with it being completely gutted and re-built, including fresh filter(s) and the screen checked/cleaned.
 
Deere makes three USA designed closed-center pumps. 2.4, 3, and 4 cubic inches per revolution. I assume you have the 3 cubic inch. Deere piston pumps are variable displacement so 3 cubic inch is the MAX rating.

RPM X Pump Displacement / 231

How much oil will be produced by a 3 cubic inch pump operating at 2600 rpm?

RPM = 2600
Pump Displacement = 3 cubic inches per rev
RPM X Pump Displacement / 231 = 33.7 gpm
 
When they flow-rated the pump, where did they do it at? Immediately behind the main hydraulic pump outlet, or through an scv? If the flow was measured between the pump and junction block, you may be losing flow through the steering, brakes, or rockshaft. If the flow was measured through an scv, not all the scv's may flow the same amount of oil regardless of where the rabbit/turtle is. Your couplers and hose tips can also restrict flow. ISO couplers and tips will flow more oil the John Deere ones. Also, make sure you have ISO tips instead of Pioneer, there is a difference.
 
One thing not mentioned is that under continuous hydraulic function use the transmission/charge pump is the limiting factor. The front pump will pump more oil than the charge pump can get to it. Mike
 
Yes and if you can return oil threw the charge circuit it will help..When I was using a power beyond block for the air pump I was dumping back to sump, but what I needed in my application was a better flow to the air pump..
 
I am not sure exactly where they checked the system, but from what I can figure out, it would seem the readings probably came from one of the SCV's. I am basing that on what was written in the narrative of the work done on the tractor. It is going into the shop here relatively soon for some repair work and I am trying to do some homework before it goes in, so that we may be able to resolve this. What I can say, is this 4640 replaced a 4630. They both were used on a prior planter, a 7100 John Deere. The hydraulic functions in lifting the planter and raising the hydraulic markers were noticeably slower on this 4640 as compared to the 4630. Neither had the SCV's upgraded to ISO couplers. This has been the one key disappointment with this tractor versus the 4630 we had.
 
When I talked about this to the representative at Worthington Ag Parts, we discussed the possibility of going to the larger main pump. I was told there was some sort of screen in the 3 cubic inch pump, and that if I went to the 4 cubic inch pump, this would no longer be the case. Is this the filter or screen you are referring to, Tx Jim?
 
I have looked into one of those pto driven hydraulic power units. The price I was quoted came in at just under $6000. If this was a JD planter, attaching it to the hitch frame would seem to be a piece of cake. Since this is a 3200 Kinze, the hitch frame is hinged so that each half of the planter can flex in uneven terrain. There is not a place to mount this pto driven unit. I have been looking at this from the standpoint that if my main hydraulic pump is weak and needs replacement, I might be able to solve this problem with a larger main pump. According to the cost I saw in the Worthington Ag Parts catalog, I seem to recall seeing the standard pump running around $800 and the 4 cubic inch pump running around $1000. I have not seen anyone who has utilized one of these pto driven hydraulic power units nor do I have any feedback, positive or negative, other than what Tim S has mentioned. Reading his comment tends to shy me away from one of those units. I am just trying to make the best informed decision I can on this. If I cannot use the hydraulic drive, it is not the end of the world. I looked at this variable rate drive as a step towards some of the precision farming practices and that I could get a comfort level with the variable rate population before taking a step further with precision. The prior owner of the planter did variable rates with precision farming technologies.
 
I responded in a prior message, B & D, and I pasted your message in that response so I could address your points and questions directly in the text. I have quite a bit to think about. I will add, this 4640 had been used on a 7100 planter for a few years, as well as a 4630 that was replaced by this 4640. From day one, lifting the planter and raising the hydraulic markers were noticeably slower on the current tractor. After the rear end was gutted and rebuilt, it was not one bit better than before. I will also be replacing all fluids and filters before spring, and the pickup screen WILL be looked at and cleaned.
 

A power beyond supply that is plumbed direct . The higher flow ISO fittings and ensure the return oil is being returned to the pump side of the transmission oil filter.
As TimS stated. Returning the oil direct to sump will bog a Dubuque , Mannheim or Waterloo closed center system .
There is a wee screen up at the front pump I'll bet the dealership missed. Sounds like some debris went through the system. If they missed the filter, no wonder low flow.
 
Around this area those that tried the variable rate drives were disappointed and went away from them, it's an intriguing idea that can give a lot of grief. Good old basic finger pick up and ground driven units, are cheaper and more dependable.
 
The screen in the front pump is mainly to screen oil for the stroke valve main oil flow does not go trough this screen, I replace this screen when I re-seal a pump and there is rarely any thing in them, but they get a new one anyway.. # 17 is the screen we are talking about..
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It seems that most modern equipment is requiring a much larger Hydraulic flow, and of course wider equipment has more cylinders to fill each time they are lifted then toss in a couple hydraulic motors to spin air systems and there you are needing a new tractor,,,sounds sorta like a marketing plan for the dealers...along with the new guidance systems luring customers in. But the fact is a pre-1996 tractors have trouble meeting the demands of some newer equipment. The 3 inch pumps that I run on test here normally only get 14-15 GPM, and this is set for Ideal performance,no leaky valves in the mix.
 
I would think you could get a direct drive PTO pump from someplace such as Surplus Center for a lot less than the price you quoted. I checked into the option when I got my vacuum planter. I think it could be done, reservoir and all, for $1000 or less. Hoses would add more, obviously. The pump does not have to be a dedicated planter pump. It just has to have enough flow and a flow regulator of some kind on it. Mike
 
Tim, experience with both a finger pickup planter and a vacuum planter, along with testing several of both kinds on my planter test stand convinces me the vacuum is the better choice these days. I would not want to go back to a finger pickup, as good as they were in their day. The vacuum plants varying seed sizes much more accurately. Mike
 
Remove the rear plug on the back of the tranycase case. Look for oil flying around there , on the bottom of the rockshaft there's a cover that can blow the gasket thus dumping return oil into the sump, causing low oil flow .
 

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