Overhaul of Ladder Trucks
Disassembly of Ladder Trucks
Disassembly of a ladder truck is done by removing the ladder and its fixtures from the vehicle body. The removed ladder is further disassembled into sections and then measured for distortion, warp and deformation and checked for crack, damage and other defects to ensure safety of the ladder.
Example of deformed ladder
Disassembling a ladder
Repair of Cylinders
A ladder truck is in danger when its ladder cylinder loses functionality. Among the ladder truck components subject to overhaul, the cylinders are particularly important.
Re-plated cylinder rod
Sliding damage in a cylinder
Replacement of Hydraulic Gear Pump
After a long time of use the gears and casing of the hydraulic pump may have wear and damage, leading to performance deterioration.
Worn/damaged gear
Disassembly and Repair of Gyro Turntable
Damage in the gyro turntable may result in a major accident. Disassembly and repair of the turntable is one of the critical maintenance items during overhaul.
Damaged gyro turntable
Gyro turntable being repaired
Disassembly and Repair of On-board Equipment
After 7 years of use, consumables including internal packing are found to have deteriorated due to wear and sliding parts are considerably damaged.
Damaged drive shaft
Disassembling equipment
Reassembling equipment
4-way solenoid valve (before disassembly)
4-way solenoid valve (after disassembly)
Replacement of Wire Ropes and Hydraulic Hoses
- Hydraulic hoses
Hydraulic rubber hoses deteriorate and get deformed due to aging. All rubber hoses should be replaced during overhaul. - Wire ropes
Ladder trucks use wire ropes in two locations: the extension device and the lifter.
Guideline for Replacing Wire Ropes
Deformation
Damage
Maintenance of Control Computers and Sensors
Unlike the conventional ladder trucks, the new model ladder trucks are fully controlled by a computer. It is thus very important to maintain the computer and connected sensors in good condition.
Printed circuit board examination
Computer for ladder control
Change of Hydraulic oil
Most of hydraulic device/machinery malfunctions and increased power consumption are said to be caused by the use of deteriorated fluid. These problems may lead to breakage or even shutdown of the overall hydraulic system.
New and old return filter elements
Appearance Inspection
The hydraulic oil is sampled from the top and bottom of the tank as well as the piping and then put in test tubes to be compared against new one in terms of color, odor and inclusion of foreign substances.
- A. Brand new
- B. Normal
- C. Needs to be changed
- D. Deteriorated
Painting, Plating and Rigging
Primer repair (including sheet metal and patty) → Wash primer coating (pink) → Painting (red) → Finishing (red)
Primer coating
Re-plating
Fixing
Internal Inspection and Examination
Test operation and internal inspection of ladder
Examination commissioned by Japan Fire Equipment Inspection Institute