Short answer: If your EC290's boom arm drifts down overnight, the cylinder rod is oily or the boom sags under load, the cylinder seals are worn and the kit should be replaced before metal-to-metal damage occurs. Kit VOE14589129 covers the boom cylinder service seals; confirm by the number stamped on your old cylinder head or the parts book for your serial range.
Symptoms of failing boom cylinder seals
- Overnight drift: the boom settles by itself with the engine off — internal bypass past the piston seal.
- Oily rod / weeping head: a film of hydraulic oil on the chrome rod after each shift.
- Sag under load: boom drops while holding a loaded bucket at mid-height.
- Cycling faster than normal: the pump compensates for internal leakage, wasting fuel.
What is inside the kit
| Item | Function |
|---|
| Piston seal + wear rings | Seal pressure between chambers, keep the piston centered |
| Rod seal + wiper (U-cup) | Hold pressure in, keep dirt out of the head |
| Head O-rings / buffer seals | Seal the cylinder head to the barrel |
Before you open the cylinder
- Record the stamped number on the cylinder tube/head — VOE numbers changed across EC290 production breaks; the stamp always wins over the model name.
- Relieve hydraulic pressure and support the boom mechanically before loosening hoses.
- Measure bore, rod diameter and stroke if the stamp is unreadable.
Installation precautions
- Clean the barrel internally; one grain of grit can kill a new seal set in hours.
- Warm seals in clean hydraulic oil before assembly; never fit dry, cold seals with metal tools.
- Tighten the head to specification; over-torque distorts the buffer seal.
- After refit: bleed air, cycle the cylinder slowly full-stroke several times at low pressure, then check for leaks.
Aftermarket vs original kits
An original VOE kit guarantees a perfect durometer and geometry match. A quality aftermarket kit does the same job at a lower cost — the difference is quality control. Ours are tested in batches, packed per kit (not bulk), and shipped with the VOE cross-reference on the bag. Compare prices in our parts catalog — search "14589129".
Frequently asked questions
How long does a seal kit replacement take?
One technician, 2–4 hours per cylinder including removal, on a bench with proper pullers.
Can I replace only the rod seal?
Possible, but not recommended: if the cylinder is opened, the labor cost of a second opening exceeds the price of the full kit.
Does VOE14589129 fit EC290B and EC290D?
Fitment depends on the cylinder supplier and serial range. Confirm with the stamped number on your cylinder before ordering.
Need VOE14589129 or another cylinder kit?
In stock, factory direct. Send the stamped number for same-day quote.