Hydraulic Cylinder Repair Tips
An increasing amount of equipment owners are handling hydraulic
cylinder repairs themselves to save time and money largely due in fact to the
relatively simple procedure. Whether you are a seasoned pro at
hydraulic cylinder repair or you could use a few pointers, these helpful tips
can get you back on the job-site in no time.
Visual Inspection and Disassembly
External leaking is the usually the first sign that the cylinder
needs to be inspected and/or repaired. Once you begin disassembly, be careful
to keep the piston rod clean & free of contaminants.
Be sure to protect all threads from damage. This is crucial as
it could lead to a costly replacement!
Taking a picture of the parts in their correct order for future
reference will be a huge time saver for you when you reassemble!
Inspect all seals for damage or
excessive wear. A pitted or grooved barrel may be the culprit if a
piston seal shows these signs of damage and will need to be replaced.
A damaged rod seal could point to a wear band/guide bushing that
is excessively worn or even a bent or scored rod. Both issues can culminate
in the weight of the rod distressing the seal which will cause failure.
Dye penetrant spray can be used to identify cracks on the
surface of the rod. Be sure to spray at all points where the diameter
Inspect the chrome for dull spots. This could indicate a bend in
the rod. In most cases, bent rods can be repaired in a press; however if the
chrome is compromised, the rod must be re-chromed or replaced.
Be sure to look for pitting and scoring of the chrome surface as
this could reduce the life of the rod seals. If the degree of the pitting
and/or scoring is too high, the rod will need to be re-chromed or replaced.
When a wear band is fitted
between the rod and head, it should be replaced during a cylinder repair due
to high load wear. When the rod is supported directly on the head, a
micrometer should be used to measure the internal diameter of the head in two
positions, 90°apart, to validate the proper circular shape.
Minimal scoring on the lands of the seal groove is not
detrimental to the functionality of the cylinder so long as the maximum
diameter of the scoring doesn’t exceed the nominal rod diameter plus .016″,(depending
Barrel & Piston Examination
Pitting or scoring of the barrel will significantly impact the
life of the piston seal. Honing the barrel to remove damage or
replacement of the barrel is recommended if the scoring or pitting is too
Slight scoring of the outside diameter of the piston will not
impact cylinder function if the minimum diameter of the piston is not less
than the nominal bore diameter minus .006″.
Piston wear bands should always be replaced during the repair on
cylinders where there are high loads on the rod.
Reassembly & Ordering Tips
- S – SPEED at which your cylinder is designed to operate
- T – TEMPERATURE range your operating system can expect
- A – APPLICATION of the cylinder & its intrinsic value to the system
- M – MEDIA (oil) type used in your system
- P – PRESSURE range of your OS
- S – SIZE of the cylinder (rod & bore) and its ancillary components
John Deere Replacement Piston Seal Kit – Order Now
Ford Replacement Seal Kit – Order Now
Commercial Replacement Reeving Cylinder Kit – Order Now
Rod Seal Installation Tool – Order Now
O-Ring Extraction Tool Set – Order Now