Hydraulic Repair Iowa - Social Proof
410 Freel Dr Ste 102, Ames, IA 50010 515-292-2599

Refilling the reservoir with makeup fluid is a critical maintenance task, as errors can lead to serious consequences. Regular need for makeup fluid indicates a leak, which must be identified and repaired to ensure proper system functioning.

Maintaining the correct Hydraulic Repair Near Me fluid level is essential. Overfilling a cold system can lead to spills through the vent breather as the fluid expands upon heating. Conversely, a low fluid level can cause pump whining and fluid aeration. In mobile hydraulic systems with small reservoirs, low fluid doesn’t necessarily lead to pump whining but can overheat the system due to inadequate cooling. It’s important to remember that the reservoir’s capacity may only match the pump’s gallon per minute flow rate. A reduced capacity from low fluid levels results in more frequent fluid circulation, leading to excessive heat before sufficient cooling.

If the Hydraulic Repair Near Me pump is situated below the reservoir, it’s normally flooded with fluid. Pump noise indicating aeration means the system is out of fluid and must be stopped immediately to avoid pump damage. Pumps above the reservoir can draw air into the system as the fluid level drops, causing aeration and potential system damage. Symptoms include pump whining, foamy fluid in the reservoir, and erratic cylinder operation. Continuing to operate in this state poses safety risks and can damage the pump.

Fluid levels are typically checked at operating temperature using a sight gauge or dipstick. Avoid filling the machine to the full mark when cold, as this leads to overfilling once it warms up. Add fluid only after the machine has warmed up, reaching the full mark.

Use only the correct fluid in the appropriate amount. Mixing incompatible fluids can damage the system, leading to costly repairs and possible warranty voidance. Check the Hydraulic Repair Near Me operation manual for the manufacturer’s recommended hydraulic oil. 

Preventing contamination during fluid addition is crucial. New fluid often exceeds the system’s contamination level, largely introduced during storage, transport, and refilling. Use a filter pump for adding fluid to the reservoir. If bulk oil contamination is an issue, use fluid from newly opened quart or gallon containers and avoid storing partially filled containers.

Before refilling, clean around the fill cap with a lint-free towel. Ensure the use of the correct, labeled fluid. Check the filler screen and relief breather. If using a funnel, ensure it’s clean, with plastic funnels preferred over metal for less contaminant retention. Fill only to the full mark and clean any spills with a lint-free towel.

A telltale sign of air in a Hydraulic Repair Near Me hydraulic system is when the plunger moves in a spongy, jerky, or pulsating manner. This is due to the compressibility of the air, which should be removed from the system. Over time, trapped air can cause oxidation, increased oil viscosity, sludge formation, additive depletion, and heightened acidity. Additionally, air can induce cavitation – the formation and collapse of vapor bubbles caused by swift changes in fluid pressure, leading to vibrations and potential damage to metal components.

Sources of Air in Hydraulic Systems

Air can enter hydraulic systems through various points like seals and fittings, or during maintenance procedures. It’s important to note that hydraulic fluids naturally contain some air. While dissolved air isn’t usually a concern, the bubbles formed during cavitation can be problematic.

Steps to Remove Air from a Hydraulic Repair Near Me Hydraulic Cylinder

  • Connect your hose to the cylinder. For double-acting cylinders, attach hoses to both ends and use a corresponding pump.
  • Position the cylinder below the pump, with the ports facing upwards, to encourage air to rise towards the pump.
  • Ensure the hydraulic pump’s reservoir is vented. Operate the cylinder at low pressure to check its functionality.
  • Perform multiple cycles of extending and retracting the cylinder, watching for any signs of uneven movement, indicating air presence.
  • Continue the process until the plunger moves smoothly and without interruption.

For further guidance, contact your local Enerpac representative.

For a comprehensive selection of hydraulic oils, cylinders, and pumps, visit our website to explore various options.


To change hydraulic oil in a frequently used machine, follow these steps:

  • Shutdown Process:
    • Turn off the hydraulic machine using the isolator.
    • Open the pressure relief valve until the pressure gauge shows zero, draining fluid from the cylinder.
    • Open the oil reservoir using a hex wrench.
  • Oil Removal:
    • Check the current oil level in the tank.
    • Get enough 25-liter containers ready for the used oil.
    • Set up the fluid removal pump, placing the extraction hose in the old oil and the output hose in an empty container.
  • Oil Extraction:
    • Start the pump, filling the containers with used oil.
    • Keep changing containers as they fill up.
    • After removing all oil, seal the containers and arrange for their disposal.
  • Cleaning:
    • Clean the inside of the tank with general-purpose cloths, discarding used cloths properly.
    • Ensure no oil residues or sludge remain. If heavy sludge is found, a system flush might be necessary.
  • Refilling with New Oil:
    • Prepare new oil drums, matching the tank’s capacity.
    • Carefully pour new oil into the tank to avoid splashes and bubbles.
    • Fill the tank up to the maximum level indicator.
  • Reassembly and Testing:
    • Secure the tank lid with the hex wrench.
    • Use the hydraulic hand pump to build pressure, then turn on the isolator.
    • Perform several operational cycles to check the system.

Caution: Only qualified personnel should handle hydraulic oil changes in heavy machinery due to the complexity and potential hazards involved.

Updating Hydraulic Fluids and Installing New Filters

Contamination in Hydraulic Repair Near Me hydraulic fluids is a common issue in regular hydraulic cylinder operations. To maintain your machinery’s efficiency, it’s important to change the hydraulic fluid regularly.

  • Disconnect the hydraulic hose.
  • Remove the hydraulic cylinder from your equipment.
  • Drain the old or contaminated fluid.
  • Clean the cylinder with a cloth to eliminate dirt and residue.
  • Reinstall the cylinder.
  • Reattach the hydraulic hose.
  • Refill with fresh hydraulic oil or suitable fluid.

To further prevent contamination, routinely replace filters before they reach full capacity (around 80%) for optimal performance.

Rotating or Alternating High-Usage Hydraulic Cylinders