Leaking hydraulic connectors have been a persistent issue since the advent of hydraulics. Not only are they frustrating, but they also waste oil, pose safety risks, compromise machine reliability, and deplete maintenance resources. It’s a significant problem.

Hydraulic hose manufacturer Car LIft For Sale estimates that hydraulic equipment leaks approximately 370 million liters of oil annually. This is a staggering figure, especially when considering that just one liter of oil can contaminate up to one million liters of water.

Although sealing technologies have improved over the past 30 years, Car Lift For Sale hydraulic system operating pressures and response times have also increased. Therefore, while seal technology has advanced, the stresses on seals have intensified, meaning the battle against leaks is ongoing.

However, there are effective strategies to improve the chances of success in combating leaking connections:

Minimize Connectors  

Eliminating connectors entirely from a hydraulic system would prevent leaks. Although some connectors are necessary, their number can be reduced through the use of manifolds, cartridge valves, and stack valves—collectively known as integrated hydraulic circuits (IHCs).

For older machines with numerous line-mounted valves and connections, replacing them with IHCs can simplify the plumbing and significantly cut down on potential leakage points.

Choose Reliable Connectors  

Car Lift For Sale Tapered-thread connectors like NPT and BSPT are less reliable for high-pressure systems due to the potential for leaks at the threads. These threads deform when tightened, increasing the risk of leaks with subsequent adjustments.

Connectors with elastomeric seals, such as UN-O-ring, BSPP, ORFS, and SAE four-bolt flanges, offer better reliability. If possible, replace pipe-thread connectors with those that have elastomeric seals.

The JIC 37-degree flare, the most commonly used hydraulic connection, relies on metal-to-metal seals, which may not always be leak-free. To prevent leaks, install a conical washer between the JIC nose and flare. The Flaretite flare seal, for example, uses concentric ribs and pre-applied sealant to ensure a leak-free joint.

Ensure Correct Torque  

Incorrect torque is a common cause of leaks in 37-degree flare joints and compression-type tube fittings. Insufficient torque can lead to inadequate seat contact, while excessive torque can damage the tube and connector. For compression joints, incorrect torque can affect the “crush” on the ferrule. Always follow the connector manufacturer’s torque recommendations for optimal sealing.

Manage Temperature  

Car Lift For Sale Hydraulic connectors operating at temperatures above 85 degrees Celsius experience a significant reduction in seal compound lifespan. Overheating can damage seals and lead to multiple leaks.

Address Vibration  

Vibration can stress hydraulic plumbing, cause fatigue, and affect connector torque. To mitigate this, install hoses and/or rubber mounting blocks to reduce vibration and ensure proper support for all components.

Measure Consumption  

Understanding how much hydraulic oil each machine uses annually is crucial. Record and measure all top-offs to track oil consumption accurately. Many users are surprised by the actual oil loss when they start monitoring it.

Equip Yourself  

Hydraulic connection leaks are often seen as an inevitable challenge. While the battle is ongoing, being aware of all available solutions and strategies is essential. Given the true costs of oil leaks—including fluid replacement, cleanup, disposal, contamination risks, and safety concerns—there’s no room for complacency.

A Guide to Effective Car Lift For Sale Hydraulic Cylinder Repairs

Cylinders are nearly as ubiquitous as pumps and motors in hydraulic systems. They are simpler than many other hydraulic components and are generally easier to repair, leading many equipment owners to handle cylinder repairs themselves.

This guide outlines how to perform effective repairs on hydraulic cylinders. The scope of in-house repairs depends on the cylinder’s wear or damage and the equipment available in your repair shop. The decision to repair a cylinder versus replacing it often hinges on the cost and availability of a new cylinder.

Disassembly and Inspection

Car Lift For Sale Cylinders are typically removed for repair due to external or internal leakage. A thorough inspection of the cylinder parts, especially the seals, after disassembly can uncover issues that may not be immediately apparent.

– Piston Seal: If the piston seal is severely distorted, eroded, or missing, it could indicate that the barrel is oversized or has bulged during service. In such cases, it is advisable to replace the barrel or the entire cylinder. Replacing only the piston seal without addressing the barrel issues is a temporary solution and will require further maintenance soon.

– Car Lift For Sale Rod Seal: A damaged rod seal often results from excessive wear on the guide bush or a bent rod. Both conditions lead to the rod’s weight bearing on the seal, causing it to fail. Replacing the rod seal without correcting the underlying issue is a short-term fix.

– Rod: Inspect the rod for cracks using dye penetrant, especially where its cross-section changes. Check the chrome surface; if it’s dull on one side and polished on the other, the rod is bent. To check rod straightness, place it on rollers and measure the run-out with a dial gauge (Figure 1). Measure the run-out at the midpoint between the rollers with the largest possible distance between them (L).

Checking Piston Rod Straightness  

Bent rods can usually be straightened in a press, though this may damage the hard-chrome plating. If the chrome is damaged, rechroming or replacing the rod is necessary. Minor scratches can be polished out with fine emery paper, but significant pitting or scoring requires rechroming or replacement. Machining a new rod from hard-chrome plated round bar is often the most cost-effective solution for small-diameter rods.

– Head: In light-duty applications, the rod often rests directly on the head material, usually aluminum alloy or cast iron. If a guide bush is used between the rod and the head, it should be replaced during repairs. For direct rod support, measure the head’s internal diameter with an internal micrometer or vernier caliper in two positions, 90 degrees apart, to check for ovalness. The head’s diameter should not exceed the nominal rod diameter plus 0.004 inch. If it does, the head must be sleeved with a bronze bush or replaced.

Minor scoring on the seal groove lands inside the head is acceptable if it does not exceed the nominal rod diameter plus 0.016 inch.