Post driver

[BZ88]

Need help troubleshooting my shaver hd8 post driver.

Have been using it for awhile so I know that everything is hooked up correctly. I was just about to finish the last few posts in a fence line when the ram would no longer lift.

Took it back to the barn to trouble shoot

1) Ram will lower but will not raise.
2) carriage can be made to move freely by mechanical means.
3) when manually raised the ram will hold position and will lower when valve is activated
4) If valve is released the ram will stop and hold at that position
5) No leaks and reservoir if full of hydraulic.
6)Tractor pump is working as there is oil flow from driver back to reservoir.
7) Valve seems to be working as I disconnected ram supply hose. Oil would flow when valve activated and stopped when valve released

 

[RickB]

Relief valve is stuck open.

 

[BZ88]

If relief valve is stuck open then it would seem that it would not hold position????

 

[RickB]

If relief valve is stuck open then it would seem that it would not hold position????

Relief valve is located between the pump and spool. Not between the spool & cylinder. A spool in 'hold' position isolates the cylinder from the PRV.

A circuit relief valve (which the Shaver valve does not have) would be located between the spool & cylinder.

 

[J_J]

If you take the OUT hose off and place in a bucket, is there fluid flow when you mover the lever to raise?

In the neutral position, fluid will flow from the PB port.

When you move the lever to raise, fluid will flow from the OUT port until the cyl is at max, and then the fluid will flow through the relief valve.

Can you raise the pounder head in the neutral position? You should not be able to.

Have you inspected the load check valve? If damaged, will give weird symptoms.

Does your valve have the safety lever?

What position is the safety valve in? It has to be set correctly to use the pounder.

Problem: Drive ram (A1) will not move or
slide freely on main carriage
channel (B1).
Possible Cause/Solution(s):
1. Guide blocks (A2) lack lubricant. Lubricate
with clean engine oil.
2. Guide blocks (A2) installed incorrectly.
Refer to Service Information section
assembly procedures for correct
orientation.
3. Incorrect clearance between main carriage
channel (B1) and drive ram (A1) I-beam.
Refer to Service Information section for
clearance specifications.
4. Hydraulic drive cylinder assembly (C1) is
not parallel to main carriage channel (B1).
Refer to Service Information section,
hydraulic drive cylinder installation, and
parallelism adjustment.
5. Main carriage channel (B1) or drive ram
(A1) is bent or damaged. Discontinue use
and order replacement parts.

Problem: Poor performance, low or no
impact, hydraulic drive cylinder will
not extend.
Possible Cause/Solution(s):
1. Weak or broken drive ram springs (C14).
2. Broken lower spring bracket (C13).
3. Bent or damaged hydraulic drive cylinder
assembly (C1).
4. Main carriage channel (B1) is binding.
5. Restricted or plugged hydraulic hose(s)
(G15, G17, G20).
6. Low or no hydraulic pressure or flow from
the machine or power source.

 

[BZ88]

Valve is a simple three position
When centered (neutral) There is flow into the tractor reservoir.
When pulling the valve there is flow into the hydraulic ram. but flow stops when in neutral)
When pushed in the ram lowers.

There is no binding on the main carriage it is able to move freely

Reminder the post driver was working for most of the day and then simply stopped

 

[RickB]

Valve is a simple three position
When centered (neutral) There is flow into the tractor reservoir.
When pulling the valve there is flow into the hydraulic ram. but flow stops when in neutral)
When pushed in the ram lowers.

There is no binding on the main carriage it is able to move freely

Reminder the post driver was working for most of the day and then simply stopped

If there is flow through a disconnected cylinder supply hose when the handle is in the raise position but no cylinder extension when the hose is connected and the handle is moved to raise, go back and read my first reply. Or look for an internal fault within the valve casting which is possible but unlikely.

 

[J_J]

Valve is a simple three position
When centered (neutral) There is flow into the tractor reservoir.
When pulling the valve there is flow into the hydraulic ram. but flow stops when in neutral)
When pushed in the ram lowers.

There is no binding on the main carriage it is able to move freely

Reminder the post driver was working for most of the day and then simply stopped

Install a hyd pressure gage and see if any pressure is developed when you raise the ram.

Qnce the ram is raised, and you go to neutral, does the ram retract on it's own.

If you stop the ram mid stream, does the ram stay in place? The ram should lock.

It is hard to imagine the relief valve stuck fully open, but remove it and check the springs and seat.

You do know that ram is an SA type cyl. Fluid goes in and out the cyl using the same hose.

Does the spool move in and out of the valve the same amount.

 

[SPYDERLK]

Valve is a simple three position
When centered (neutral) There is flow into the tractor reservoir.
When pulling the valve there is flow into the hydraulic ram. but flow stops when in neutral)
When pushed in the ram lowers.

There is no binding on the main carriage it is able to move freely

Reminder the post driver was working for most of the day and then simply stopped

Does the remote you are supplying the driver from have a float position?

 

[J_J]

Question is is he using the PB from an up stream valve or a work port from a remote valve bungeed open.