About This Process

Applicable Machines:

This process is applicable only for Agrowplow hydraulic shank deep rippers with a single outlet on the hydraulic cylinder. This includes (but not limited to) the AP11, AP31, AP51, AP71, AP81, and AP91 hydraulic plough models.

Note: This procedure is not relevant for the APx2 range of hydraulic ploughs with dual outlets on each cylinder. Please consult the APx2 Operators Manual for the relevant procedure.

Why should you do it?

Plough hydraulic systems require consistent hydraulic pressure to ensure the shanks break out at the correct pressure. Air can be introduced into the system through normal use and should be purged regularly. As air builds in the hydraulics, it causes the shanks to break out more frequently. It can also cause premature wear in the hydraulic cylinders and in some cases cause the end caps on the cylinders to break.

Refreshing the oil from the tractor will allow correct breakout operation.

When should you do it?

Air should be purged from the hydraulics as part of your pre-season setup and as part of your daily pre-operational checks. If done regularly, this process should only take a few minutes prior to using the ripper. 

Identifying air in the hydraulic system:

Please always inspect and confirm that the hydraulic system is bled. Below are some hints on how to inspect for air in a closed-circuit hydraulic system.

1. Remove all hydraulic pressure from your Agrowplow deep ripper. (ie set to 0 psi).
2. Remove ISO fittings and press on the plough frame to ensure no residual hydraulic oil pressure.
3. Engage the tractor park brake and raise the shanks off the ground.
4. Apply a steady amount of force to the bottom of the shank (tip: push with your foot). 

If the shank can be pushed back easily, there is a good chance there is air in the system. 

Another indication is that the end caps of the cylinders can be broken. This will only happen if there is air in the system and the flow restrictor can not work properly.

Air in the hydraulic system can cause the hydraulic cylinder caps to break.

A correctly primed hydraulic system will have very little travel.

If the shank is tight and can not be moved further back than a couple of inches and a tapping sound can be heard at the top of the shank, this means the system is charged.

If you can break the shanks back by pushing on the blade with your foot, a hydraulic purge is required.

Purging the hydraulic system of air:

Preparation

Ensure your tractor and plough are parked on flat, level ground such as turf with the tractor park brake engaged. Do not perform this operation on a hard surface such as concrete, as this will not provide enough surface for the plough blades to catch and gain sufficient leverage to break back while still supporting the weight of the frame.

Method

1. Fully raise the transport wheels into the upright position so the plough is resting entirely on the shanks.
2. Set the tractor remotes to the neutral position. Slowly drive the tractor forward (less than 1km/hr) until the shanks are completely broken back and the plough frame is lowered to the ground.
3. Slowly drive forward until the shanks are entirely broken back and the frame is lowered to the ground.
   
4. Charge the plough hydraulic system by releasing the tractor park brake and setting the gear to neutral. This will allow oil to flow back into the plough hydraulics and slowly pull the tractor back as the frame rises and the shanks reset.
5. Watch the plough hydraulic pressure gauge to ensure the pressure remains until 1,000psi. Pressures above 2,000psi can make the oil and air mix together, causing a honeycombing effect.
6. Set the hydraulic pressure back to 0psi and manually check the shank breakout again as per the first point in how to identify air in the system. Repeat this process as many times as is needed to ensure the shanks don’t break back from manual pressure - usually 2-3 times is sufficient.