Cylinder Division - Europe

Cylinder Division - Europe - Solutions
Cylinder Division - Europe - Solution
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Hydraulic Cylinders - Repair or Replace?

Cutaway tie rod cylinder


If a drop in performance has occurred or leakage is evident, a hydraulic cylinder requires attention. An initial, visual inspection should be carried out with the cylinder in place.

  • Is the cylinder leaking?

Hydraulic fluid beneath the gland or dampness on the piston rod indicates worn cylinder rod gland seals. This can be rectified using a Parker Gland Service Cartridge Kit.

  • Tip – before replacing the gland, consider why wear has occurred. Worn or misaligned mountings result in side-loading of the gland and piston bearing surfaces, and will cause rapid failure of any replacement parts. If wear is identified, the cause should be corrected before a repair is carried out.

  • Is the piston rod bent or scored?

Examine the extended piston rod for condition. If there are signs of pitting or scoring, or if the rod is bent (buckled), the hydraulic cylinder will need to be overhauled. If extensive work is required, replacement may be a quicker and more cost-effective option.

  • Tip – before overhaul or replacement, consider why damage has occurred. If the piston rod is bent and the major force is applied on the ‘push’ stroke, is the piston rod strength adequate for the load? Are the cylinder and load in alignment? Is the load which the hydraulic cylinder is pushing able to move freely?


  • Are the mountings secure and in good condition?

A wide variety of mounting styles for hydraulic cylinders is available. With fixed mountings, ensure that all bolts are tight and that there is no evidence of movement between the mounting surfaces. Where pivot mountings are used, check for adequate lubrication and condition. Worn mountings are a common cause of misalignment and should be repaired or replaced.

  • Tip – correct grades of mounting bolt and figures for torque loading are shown in the relevant cylinder catalogue. Click here for product catalogues, select the appropriate cylinder series and choose ‘Mounting Information’ from Bookmarks.


  • How do I proceed?

To obtain seal kits or parts to repair or rebuild a hydraulic cylinder, or to specify a replacement cylinder, the precise specification of the existing cylinder is required. This can be found from the cylinder’s model code or serial number.

The model code is shown on a plate attached to the head or cap of the hydraulic cylinder. If the plate is damaged or missing, the cylinder can be identified from its stamped serial number, usually found on the head. Please contact us for accurate identification by serial number.

A typical model code for a hydraulic cylinder is 100 – C – K – JJ – P – HMI – R – N – S – 2 – 4 – M – C – 200 – M – 11 – 44, where:

100      -     bore (mm)

C          -     head end cushion (where fitted)

K          -     double rod cylinder (where specified)

JJ         -     type of mounting

P          -     mounting modifications (where specified)

HMI    -     cylinder series

R          -     port type

N         -     piston type

S          -     special features (where specified)

2          -     piston rod number (various diameters available)

4          -     piston rod end style (male/female, thread etc.)

M        -     rod end thread

C          -     cap end cushion (where fitted)

200      -     stroke (mm)

M        -     fluid type and temperature range

11        -     port positions

44        -     air bleed positions (where specified)

A full description of these options is available from the relevant cylinder catalogue – click here to access.

  • To obtain a Gland Cartridge Service Kit

Gland cartridge service kits are selected by reference to the diameter of the hydraulic cylinder’s piston rod. A typical kit code has the form RG2HM0181, which denotes:

RG    -    rod gland kit

2HM    -    HMI/HMD series cylinders

018    -    18mm diameter rod

1    -    standard seals for mineral oils, -20°C to +80°C temperature range

Full details of service kits, with fitting instructions, are shown in the hydraulic cylinder maintenance bulletins – click here to access. Gland wrench and gland spanner tools of the correct size should be used to avoid damage to the new gland and piston rod.

  • Major overhaul or replacement of the hydraulic cylinder

Where more extensive work is required or where the facilities to carry out an efficient repair are not available, the hydraulic cylinder should be returned to a Parker authorised repairer for overhaul – see ‘Where to Buy’ above. For both repair and replacement, please supply the model code number as shown on the model code plate, and the serial number if visible.


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