Hydraulic jacks are a common piece of equipment used in automotive repair shops, service centers and for general maintenance and repairs in the industrial maintenance sector. They can lift heavy loads with the least amount of physical effort. At times, the hydraulic jack can lose pressure which will cause the lift to fail and no longer allow the load to be lifted or sustained.
Hydraulic pressure loss can occur in a jack and can cause the jack to stop rising slowly, or fall quickly when loaded. There can be many factors for the loss of hydraulic pressure in a jack and troubleshooting some of the possible factors can help identify potential repairs to restore functionality.
Signs That Your Jack Is Losing Hydraulic Pressure
As you read through the following sections you will discover that there are numerous warning signs that might indicate that there is a drain problem that is not being properly addressed. Here are some of the common warning signs that can let you know that drain repairs are required:
- The jack fails to lift the load fully
- The jack lowers slowly while supporting a vehicle
- The pump handle feels loose or ineffective
- The jack requires excessive pumping
- Visible hydraulic fluid leakage
These are symptoms of low pressure hydraulic system.
Common Causes of Hydraulic Pressure Loss
1. Low Hydraulic Fluid Level
One of the most common reasons for pressure loss is insufficient hydraulic oil inside the jack.
The hydraulic fluid is what creates pressure to lift the lifting arm. If there is too much leakage or too much evaporation of the fluid, the hydraulic jack will not have the right amount of pressure to lift.
Solution
- Locate the oil filler plug
- Check the hydraulic fluid level
- Refill with the manufacturer-recommended hydraulic oil
Avoid overfilling, as this can also affect performance.
2. Air Trapped in the Hydraulic System
Air in the Hydraulic Chamber can interfere with the pressure of the lift and may cause spongy or uneven lifting. One contributing factor is the location of the hydraulic reservoir on some models. On these models, the reservoir sits directly above the hydraulic chamber, which means air entering the chamber can enter from the reservoir.
This often occurs after:
- Improper storage
- Fluid replacement
- Extended periods of inactivity
Solution
Bleeding the hydraulic system can remove trapped air:
- Open the release valve
- Pump the handle several times without load
- Close the valve and test lifting performance
This process helps restore proper pressure.
3. Worn or Damaged Seals
Hydraulic jacks use rubber seals and O-rings to keep the hydraulic pressure inside the jack. These seals can deteriorate and crack over time allowing hydraulic pressure to leak inside the jack.
When a seal fails the jack may lift initially but slowly fall under load.
Solution
- Inspect seals for damage
- Replace worn O-rings or seal kits
- Service the hydraulic cylinder if necessary
Regular maintenance helps extend the lifespan of these components.
4. Contaminated Hydraulic Oil
Hydraulic Fluid Contamination Hydraulic fluid contamination can occur as a result of dirt, water or other contaminants entering the hydraulic system. This can result in hydraulic fluid degradation which can lead to hydraulic system malfunction or damage.
Contamination may result from:
- Poor storage conditions
- Old hydraulic fluid
- Infrequent maintenance
Solution
- Drain the old hydraulic fluid
- Clean internal components if needed
- Refill with fresh hydraulic oil
Keeping the system clean ensures consistent hydraulic pressure.
5. Overloading the Jack
Using a jack over rated capacity can overload the hydraulic system and cause pressure failure.
Heavy duty applications such as lifting commercial vehicles using truck jacks calls for heavy duty lifting equipment.
Always verify the load capacity rating before lifting a vehicle.
Preventive Maintenance Tips
Proper maintenance reduces the likelihood of hydraulic pressure issues.
Recommended practices include:
- Regularly checking hydraulic oil levels
- Inspecting seals and components for wear
- Cleaning the jack after heavy use
- Storing the jack in a dry environment
- Avoiding overload conditions
Routine inspections help detect minor problems before they become major failures.
When to Replace the Jack
Hydraulic Car Jack Repair Note: In the event of hydraulic cylinder damage or structural damage it may not be worth the cost to carry out repairs to a hydraulic car jack.
Replacement may be necessary if:
- The jack repeatedly loses pressure after repair
- Structural components are bent or cracked
- The repair cost exceeds the equipment value
The tools and products that are used in professional workshops where large vehicles are frequently lifted and moved using truck jacks require the highest quality and performance.
Conclusion
HYDRAULIC PRESSURE LOSS IN A JACK IS USUALLY A RELATIVELY EASY PROBLEM TO RESOLVE, ESPECIALLY IN TERMS OF SAFETY AND CONTINUATION OF CURRENT MAINTENANCE. PROBLEMS INVOLVING HYDRAULIC PRESSURE LOSS IN A JACK ARE USUALLY THE RESULT OF PREVENTABLE CIRCUMSTANCES. FOR EXAMPLE, LOW HYDRAULIC FLUID IN THE JACK, AIR IN THE HYDRAULIC SYSTEM, OR FAILURE OF SEALS.
If the symptoms are noticed early and the repair is done according to the procedure, the jack can be returned to full function and the lifting operation completed in a safe manner. Contact Stan Design for all of your lifting needs. High quality lifting equipment provides the long life, safety and performance required for the severe automotive and industrial applications.