A puddle of oil under the machine and a slowly lowering loader arm. Your hydraulic cylinder has just given up. The first thought of most mechanics and farmers? "I'll buy a set of seals for 50 PLN, install them, and be done with it."
Unfortunately, reality can be brutal. Installing new seals on damaged components is a waste of money – a new seal will wear out after just a few hours of operation. When is it worthwhile to resuscitate an old actuator, and when is the only sensible option to buy a new one?
BRhydraulic experts have prepared a list of the most common failures that will help you make the right (and most profitable) decision.
1. When is it enough to just replace the seals?
Repair kits (O-rings, wipers, sealing packages) are consumable items that simply wear out, harden or wear out over time from normal operation.
Replacing seals only makes sense when:
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The piston rod (chrome rod) is in perfect condition: It is smooth as a mirror, has no chips, scratches you can feel under your fingernail, or rust.
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The leak occurred suddenly: For example, due to the oil overheating (the seals hardened) or dirty oil being poured in.
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Cylinder Losing Strength (Internal Leaking): If the arm sags under load but there's no visible leak, the culprit is the seals on the main piston inside the tube (also known as internal leakage). If the cylinder isn't scratched internally, new seals will solve the problem.
2. When do you need to buy a new actuator (or have it expensively rebuilt)?
There are mechanical damages that even the most expensive gasket won't fix. In such cases, the cost of having the part fabricated at a lathe shop often exceeds the cost of a new cylinder.
A. A scratched or bent piston rod is a death sentence for seals. Even the tiniest, sharp scratch on chrome acts like a knife – it will cut the lip of the new seal wiping gasket with each insertion and removal.
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Bent: If the cylinder has "buckled" (bent into an arc from too much weight), the rod will not fit straight into the gland. The piston rod is only fit for scrap.
B. "Swollen" tube (cylinder). This is the result of excessive pressure (e.g., a stuck relief valve) or a powerful impact on the load. The cylinder tube slightly increases in diameter over a certain section (resembling a barrel).
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Symptoms: The cylinder is stuck in one place or loses force (leaks) only in a specific stroke. The cylinder needs to be replaced.
C. Rust Flaking and Pitting Under the Chrome. If the machine has been sitting outdoors for a long time with the actuator extended, pitting will appear on the rod. Pieces of flaking chrome will immediately tear the gland. Polishing this with sandpaper is a myth – you'll reduce the rod diameter, and the actuator will still leak.
D. Cracked or Stretched Mounting Lugs. When the actuator lug (where the pin enters) is worn and has excessive play, the machine will jerk. Although the lugs can be cut off and welded, for smaller and medium-sized actuators, it's cheaper and safer to buy a new unit.
Summary: Cost Calculation
Before ordering seals, disassemble the actuator, wash it, and carefully inspect it under a strong light. If the rod is smooth, buy a repair kit. If you see deep scratches, rust, or a bend, save yourself the hassle and double the work.
In the BRhydraulic store you will find both high-quality sealing packages and brand new, reinforced ones. hydraulic cylinders ready to work in the harshest conditions.
