The hydraulic hose of an excavator can be said to be the "blood vessel" of the entire machine, responsible for the transmission of high-pressure hydraulic oil, directly determining the smoothness of movements such as the boom, forearm, bucket, walking, and turning. The construction site has complex working conditions, frequent heavy loads, and large temperature differences. Hydraulic hoses can withstand high-pressure impacts of 20-40MPa for a long time, making them one of the most easily worn and faulty components of the entire machine.
Many machine operators will blindly replace pipes when encountering pipe bursts, oil leaks, or stuck movements, but they cannot find the root cause, resulting in repeated breakdowns, frequent repairs, and fuel and labor costs. Today, we will provide a detailed breakdown of the 6 common faults in excavator hydraulic hoses, including fault symptoms, core causes, solutions, and prevention techniques. Even beginners can quickly understand them.
1, Hose burst: the most dangerous and sudden fatal malfunction
This is the most common and harmful fault on construction sites, which often occurs in high-pressure main oil pipes, large arm and small arm pipelines. It often bursts without warning, accompanied by piercing pressure relief noise and a large amount of hydraulic oil splashing, directly leading to equipment failure, pressure drop, and even causing safety accidents in severe cases.
Root cause of core malfunction
-Pressure overload impact: Long term heavy load operation, vehicle holding operation, hydraulic system instantaneous pulse pressure exceeding the rated pressure range of the hose, repeated impact causing the steel wire layer of the pipe wall to break, the rubber layer to crack and burst
-Inconsistent quality/selection of hoses: using inferior low-pressure hoses instead of high-pressure hoses, mixing braided and wrapped pipes, mismatched pipe diameter and pressure parameters, unable to adapt to high-pressure working conditions of excavators
-Aging due to temperature difference between hot and cold: Low temperatures in winter make rubber harder and brittle. During operation, the internal high-temperature oil expands, and the huge temperature difference between the inside and outside generates stress. Long term repeated action causes hidden cracks in the pipe wall, ultimately leading to bursting
-Fatigue aging and prolonged use: The hose has exceeded its service life, the steel wire layer has rusted, the rubber layer has aged and hardened, the toughness has significantly decreased, and slight pressure fluctuations can cause damage and explosion
Handling and Prevention
After the explosion, the machine must be stopped immediately and replaced with a genuine high-pressure hose of the same specification. It is prohibited to temporarily assemble and use it. Avoid prolonged holding and vigorous operation in daily life, regularly check the pressure of the overflow valve to prevent the system pressure from exceeding the standard; In the cold winter, start by idling and preheating to reduce temperature difference stress damage.
2, Joint oil leakage/seepage: the most common and easily overlooked minor fault
Different from the large-scale oil leakage caused by bursting pipes, this type of fault is often manifested as slight oil leakage, hanging, and dripping at the joint threads and clamping points. Initially, it does not affect the operation and is easily overlooked. Over time, it can lead to hydraulic oil loss, system intake, insufficient pressure, and secondary problems such as weak operation and shaking.
Root cause of core malfunction
-Aging and failure of seals: The O-ring and combination gasket of the joint have hardened, cracked, and deformed after long-term use, losing their sealing function, which is the main cause of oil leakage
-Loose and detached joints: High frequency vibration during excavator operation causes gradual loosening of joint nuts and threaded connections, resulting in increased sealing gaps and oil leakage
-Poor crimping process: The crimping amount of the hose assembly is too large or too small, the joint is not tightly attached to the hose, and the seal is not tight; The selection of braided and wrapped pipe joints is mixed, resulting in poor compatibility
-Thread wear and damage: Frequent disassembly and violent twisting can cause the joint threads to slip and wear, making it difficult to lock tightly
Handling and Prevention
Minor oil leakage can be cleaned first and then moderately tightened. If the leakage still persists, replace the seal with a brand new one directly; Damaged threads, joints, or oil leakage at the crimping point require re crimping or replacement of the assembly. Daily maintenance focuses on inspecting pipeline joints, avoiding violent disassembly, and regularly replacing aging seals.
3, Wear and tear of pipe wall: physical damage caused by working conditions
Excavators frequently bend, extend, and rotate their large and small arms, causing long-term friction and collision of pipelines. This can lead to wear, peeling, and thinning of the outer rubber layer of the pipeline wall, and in severe cases, oil leakage due to abrasion. This often occurs when the pipeline is in contact with the frame or when adjacent pipelines cross and rub against each other.
Root cause of core malfunction
-Unreasonable installation and wiring: The pipeline routing is too tight and there is no reserved expansion allowance. During operation, the pipeline is pulled and rubbed against the machine body
-Lack of protection: No protective tube, rubber pad, or wear-resistant sleeve installed, and the pipeline directly contacts and rubs against the metal frame and bolts
-External force collision and scratch: Construction site gravel, slag, steel bars collide with pipelines, or tools scratch the pipe wall during disassembly and maintenance
Handling and Prevention
Slight wear on the surface can be temporarily protected by adding an anti-wear sheath. If the skin is worn, damaged, or the steel wire layer is damaged, it must be replaced directly to prevent the pipe from bursting under high pressure. Newly installed pipelines must be wired in a standardized manner, with allowance for expansion and contraction. Protective accessories should be installed at all intersecting and fitting positions to prevent hard friction.
4, Hose bulging and deformation: warning fault for internal damage
It belongs to the precursor fault of tube explosion! Visible to the naked eye are local bulges, bulges, and twisting deformations on the pipe wall. During operation, the bulge position will expand and contract with pressure fluctuations, which may not affect use. However, the internal steel wire layer has already broken and layered, and may burst at any time.
Root cause of core malfunction
-Internal steel wire layer fracture: Long term high-pressure impact and instantaneous pressure overload lead to internal steel wire fracture, local pressure bearing capacity failure, and rubber layer protruding outward
-Twisted installation of pipelines: During installation, the hose is forcibly twisted and twisted, and during operation, it is continuously subjected to torque, resulting in layered deformation of the internal structure
-Local compression damage: The pipeline is compressed by heavy objects and subjected to long-term pressure, resulting in damage to the internal structure and local bulging deformation
Handling and Prevention
If bulging, twisting, or deformation is found, it is forbidden to continue working and the hose must be replaced immediately. Do not have a lucky mentality. When installing the hose, ensure it is naturally straight, avoid twisting, pulling, and squeezing, and strictly match the length of the pipeline.
5, Hose hardening and cracking: natural aging fault
Long term outdoor operations, exposure to wind and sun, and erosion from high-temperature oil stains can cause the outer rubber layer of the hose to lose its elasticity, become stiff, white, and crack, with the surface covered in fine cracks. The cracking problem will become more severe in low-temperature environments.
Root cause of core malfunction
-Natural aging and oxidation: Rubber materials undergo oxidation and aging due to long-term exposure to air, ultraviolet radiation, and rainwater, resulting in a significant decrease in elasticity
-High temperature oil pollution erosion: Long term exposure to high temperature hydraulic oil, oil pollution, and dust accelerates rubber hardening and brittleness
-Overdue service: The normal service life of hydraulic hoses is generally 1-2 years, and excessive use will inevitably lead to hardening and cracking
Handling and Prevention
Replace hoses with large areas of cracking and hardening directly to avoid cracking and oil leakage during low-temperature operations. Perform daily equipment cleaning to reduce oil accumulation, regularly check the aging status of pipelines, replace them upon expiration, and ensure they are not used beyond their expiration date.
6, Soft hose suction and inner layer detachment: internal blockage fault
This type of malfunction is relatively concealed, with visible suction and depression in the low-pressure section of the pipeline, accompanied by slow, weak, stuck, and abnormal equipment movement. After disassembly, it can be found that the rubber inside the hose has peeled off and peeled off, blocking the oil circuit.
Root cause of core malfunction
-Inner rubber aging and detachment: Poor quality and severe aging of the hose, detachment of the inner rubber from the steel wire layer, and blockage of the oil circuit due to debris detachment
-Excessive negative pressure: blockage of return oil and suction pipelines, filter blockage, excessive negative pressure in pipelines, resulting in hose being sucked and deformed
-Oil deterioration and corrosion: Hydraulic oil that has not been replaced for a long time, with excessive impurities and acidification deterioration, corrodes the inner layer of the hose, causing damage and detachment of the inner layer
Handling and Prevention
Immediately replace the failed hose, clean the hydraulic oil circuit, replace the hydraulic oil and filter element, and investigate the problem of pipeline blockage. Regularly replace hydraulic oil, keep the oil clean, and avoid poor quality oil corroding pipelines.
Summary: Key points for avoiding pitfalls in hydraulic hose faults
The vast majority of hydraulic hose failures in excavators are not simply caused by wear and tear, but by incorrect installation, use, and inadequate maintenance. Explosions of pipes are mainly caused by excessive pressure and poor selection, oil leaks are mainly caused by seal aging and vibration loosening, wear and deformation are mainly caused by non-standard installation, and aging cracks are mainly caused by expired service and environmental erosion.
To reduce malfunctions and repair costs, remember the three core points: selecting the right genuine and compatible hose, standardizing installation and wiring, conducting regular inspections and maintenance (checking for leaks, wear, and aging), and eliminating violent and overpressure operations. This can significantly extend the service life of the hose and avoid sudden failures and shutdowns on site.
