Shaver HD10 Post Driver on JD 990?

[Amelia Farms]

I have a friend that has offered to loan me his Shaver HD10 post driver to drive some fence posts. I am not sure if my JD 990 has enough hydraulic flow to run the driver. Shaver web site says the HD10 needs 12GPM @ 1500 PSI. Specs on my 990 hydraulics say:

Type: open center
Capacity: 5.5 gal [20.8 L]
Pressure: 2262 psi [156.0 bar]
Valve flow: 8.5 gpm [32.2 lpm]
Total flow: 13 gpm [49.2 lpm]
Steering flow: 4.5 gpm [17.0 lpm]

Do I go by the total flow or just the valve flow? Anybody ever tried the HD10 on a 990. I have about 300 posts to put in the ground and sure would like to be able to use the driver.

 

[RickB]

Less than 12 GPM flow means the hammer will raise slower than if the tractor delivered 12 GPM. Gravity does the pounding, and the flow difference won't affect driving performance.

The absolutely critical thing is having a free flow, unrestricted hydraulic return. DO NOT connect both hoses to your SCV, return the oil someplace like the hydraulic fill cap.

 

[Amelia Farms]

I have the power beyond kit on the 990, so I assume that I would hook up there since the post driver has its own control valve, does that sound right?

 

[RickB]

Is your 3PT hitch operable when the PB circuit is in use?
If no, you will have difficulty positioning the driver from post to post.

If yes, you may have more backpressure in the return circuit than the driver will tolerate. I know quite a bit about open center hydraulic systems and Shaver hydraulic requirements, but am not intimately familiar with your 990.

 

[Amelia Farms]

If I understand it correctly (and I may not), the PB would not have any effect on the 3 pt lift, but I am not sure that I have ever tried it. The way I understand it, the power beyond is simply a pressurized hydraulic loop. When not in use, the PB hose just plugs from the outlet back to the inlet. When you have an attachment hooked to it, the loop then incorporates that attachment (which must have its own valve).

If I read the Shaver info right, the hydraulics raise the ram, and then gravity and 2 springs bring the ram down. I suppose if you did not have enough flow/pressure it might not be able to overcome the springs?

Does any of that make sense?

 

[RickB]

If I understand it correctly (and I may not), the PB would not have any effect on the 3 pt lift, but I am not sure that I have ever tried it. The way I understand it, the power beyond is simply a pressurized hydraulic loop. When not in use, the PB hose just plugs from the outlet back to the inlet. When you have an attachment hooked to it, the loop then incorporates that attachment (which must have its own valve).

If I read the Shaver info right, the hydraulics raise the ram, and then gravity and 2 springs bring the ram down. I suppose if you did not have enough flow/pressure it might not be able to overcome the springs?

Does any of that make sense?

The PB/3PT question relates to where the oil flow goes upon return from the loop/attached implement. From your description, I would say that the PB is not an acceptable place to connect the driver due to the return flow path.

Hydraulic pressure is is the force that acts against the return springs on the driver. Without question your 990 has sufficient pressure to act against the springs. The limited flow (GPM) would determine the speed at which the driver's maul is raised. It will be fast enough to drive posts.

Connect the driver's valve supply hose to your tractor's SCV connection and the return line to the hydraulic fill cap. I know with certainty that connection will work as Shaver intended.

 

[Amelia Farms]

Well, I went over to take a look at the post driver, and you are indeed correct, the return line is huge, 1" ID. I don't see any problem plumbing into the fill port with a few fittings that I can rig up myself. However, on the supply side, I seem to remember that the power beyond warns to always keep the loop complete, either with its own hose connecting the in/out, or with whatever attachment is being used with the power beyond. Any idea if it is ok to use the supply side from the power beyond and dump back into the fill hole, with nothing going into the return side of the power beyond?

Edit to add:
Looks like maybe I need to add a selector valve that will plumb the supply either to the driver or back into the PB inlet side or the 3 point will not work when the PB is supplying the driver.

So in summary, looks like I need to plumb the PB supply side to a selector that supplies either the driver or goes back to the inlet on the PB to supply the 3 point, and also plumb the return line off the driver directly into the hydraulic fill hole. Do I have it right now? ( I don't have any SCV hookups on the 990 )

 

[RickB]

You would probably be better off connecting the supply to one of the couplers supplying the bucket tilt circuit of your loader (uncouple both hoses for that circuit).

Using the PB as a supply for the driver will preclude you from using the 3PT hitch to position the driver between posts (as I said before).