Series Cylinders (Master and Slave(s)) can sometimes exhibit undesirable behaviors such as creep (drift or movement when the hydraulic cylinder is not in use) or failing to stay synchronized (not extending and retracting at the same rate). Below is a brief over view of some of the possible conditions that contribute to cylinder creep, drift or the series cylinder getting out of sync. Keep in mind that the cylinders are only part of the hydraulic circuit and there can be other contributing causes.
Cylinder rod measurement:
Cylinder by-pass is a common field issue in Series Cylinder Systems, and a system review is required to determine the problem
- Extend cylinders to the re-phasing position and lower hydraulics approximately 2"
- Then immediately disconnect the hydraulics from the tractor
- Measure the length of the extended cylinder rod on each cylinder
- Leave implement to stand for some time, i.e. 3 hours
- Re-measure length of rods again and compare before and after measurements
Please note: Variation can be expected if implement is left over a period of time where the temperature change affects the hydraulics by contraction or expansion. Warm to cooler temperatures will cause the series cylinders to move. Make sure measurements are taken at similar temperatures.
- When the 'suspect' cylinder has been identified, it is important that disassembly is carried out in a clean environment. The scoring of barrels and piston seals will usually indicate contamination of some type has entered the system
Air in the system:
If one or all of the cylinders drift down or the system is 'spongy' air is likely present. Check for air bubbles going back to tank or by removing the return line and catching oil in a clean container. With the rod clevises disconnected and the cylinders vertical, hold in the re-phasing position until no aerated oil flows. Hydraulic oil flow should be kept to a minimum minimize heat while purging the air from the system.
Please note: Check the reservoir levels when carrying out this exercise. Once the air has been pushed out of the system the reservoir can become low. This can introduce air in to the system again.
Miss-staged series cylinders:
Over a period of time the series cylinders may become miss-staged due to seal by-pass or differences between the rod side of the master cylinder and the extend side of the slave cylinder(s). To restage the cylinders it is necessary to extend them to the re-phasing position of for 30 seconds to 1 minute. Retract and then extend the cylinders to ensure that they are working evenly and staged with each other. It may be necessary to repeat this process.
Catalog Pages and Parts Book can be found Here