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05.19M142J3
TROUBLESHOOTING - PHASING HYDRAULIC CYLINDERS
[Note: the numbers in brackets below refer to the item numbers on the hydraulics part pages (page 54 & 55)]
The two cylinders are connected in series, such that each moves together to provide a level lift of the implement.
When the implement is RAISED, oil delivered from the tractor is directed to the piston end of the master cylinder (5), oil from the rod
end flows to the piston end of the next cylinder (4), and oil from the rod end of (4) flows back to tractor. The volumes of the cylinders
are matched so that both cylinders extend and retract simultaneously.
To ensure that all cylinders begin work "in phase", each cylinder has a "phasing bypass" hole in the barrel that allows a small volume of
oil to pass across the piston when the cylinder is fully extended (implement fully raised).
To achieve levelling of the implement (initially, or after storage, or as a result of one cylinder having an imperfect piston seal) the
implement should be:
- Fully raised,
- The tractor control valve be held in the raise position with the tractor at idle (it may require holding the valve for several minutes to
fully purge the system),
- All cylinders be viewed separately to ensure that they have reached full extension (cylinder travel has ceased),
- The tractor valve is then released and the implement can be lowered, levelled with the levelling screw assembly on the hitch, or
transported, as required.
Should a leaking piston seal be suspected, identify cylinder by:
- Phasing the implement as above,
- Lower implement slightly, but with tynes still clear of the ground,
- Close the needle valve (16) to ensure no flow back to tractor,
- Measure the shiny rod extending from each of the cylinders,
- Leave the implement stand long enough to be able to measure any change in the dimensions measured (overnight, and not in direct
sunshine is preferable).
The first cylinder in the series, that has "dropped" is at fault. If only one has "dropped", it is at fault. If both have "dropped", the "master
cylinder" (5) is at fault
This of course assumes no external leakages from any of the cylinders, or their connecting plumbing.
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