Hydraulic Repair Kits: JCB Cylinder and Hema Pump Seal Sets

Open up a leaking cylinder or pump and you are left holding a handful of sealing elements: piston seal, rod seal, wiper, guide rings, O-rings and back-up rings. Measuring and sourcing each of them one by one takes time and carries risk — if a single item is missing or comes in the wrong size, the machine has to come apart again.

A repair kit removes that problem: every sealing element for a given cylinder or pump model arrives in one package, in the correct size and the correct material. The most expensive part of an overhaul is not the parts but the time the machine stands idle; using a kit shortens it.

Stock covers three families. The first is the Kastaş JB-991 series for construction machinery cylinders; the codes carry the original JCB number (JB-991/00110, for example) and are searched by that number directly. The second is the Hema 0P1, 1P1, 1PN, 2P1 and 3P1 series kits for pumps, matched by the series code on the pump label. The third is the MR, MH, MM and MT series kits for hydraulic motors. Seal kits for pneumatic cylinders are also carried.

The one critical piece of information when ordering a kit is the model and serial number. Two cylinders that look the same bore may use different seal profiles; it is model matching, not dimension matching, that counts. Where the label cannot be read, you have to work from the size and profile of the seals removed — in that case selecting items individually is safer than a kit; for profile codes see the «Hydraulic Seals, Nutrings and Wipers» page.

Two points must not be skipped during assembly. Seals should be lubricated with system oil before fitting, and an assembly sleeve used where they pass over sharp corners and threads — most early leaks come from a seal cut during installation. Second, the condition of the rod and bore surfaces should be checked while the seals are renewed; a new seal fitted to a scored rod will leak again before long.