Why Is My Hydraulic Cylinder Leaking? Common Causes Explained
Most leaking cylinders come down to a worn rod seal or piston seal, not a cracked barrel. A strip-down and reseal usually solves it — replacement is only needed when the rod is scored or the barrel is damaged.
Rod Seal Wear Is the Usual Suspect
The seal that wipes the rod as it retracts takes the most abuse of any component in a cylinder — dust, grit and general wear gradually let it start weeping oil along the rod. This is the most common cause of a “slow but not dead” cylinder.
A Scored Rod Changes the Diagnosis
If the chrome rod has visible scratches or pitting, a new seal will fail again quickly because it’s riding over damaged metal. In that case the rod usually needs to be re-machined or re-chromed before resealing makes sense.
Internal Leaks vs External Leaks
Oil weeping around the rod is an external leak and usually just a seal job. A cylinder that drifts down under load with no visible oil outside it points to an internal leak past the piston seal — still generally fixable with a reseal, just a different seal kit.
Don’t Assume It’s a Write-Off
A leaking cylinder often gets condemned and replaced when a strip-down and reseal would have done the job for a fraction of the cost. It’s worth getting an honest assessment before ordering a new ram.
Need this looked at rather than just read about? Our Hydraulic Cylinder Repairs & Supply service covers exactly this.