Diagnosis area
Swing, travel and drive assemblies
Motor and reduction-gear complaints: slow swing, weak travel, run-away, noise and metal in the gear oil.
Guides in this area (3)
Each guide lists the checks in the order a workshop should work through them, what each result means, and which parts usually solve it.
Swing slow, weak or drifting to one side
Swing, travel and drive assemblies
Slewing feels sluggish or refuses to hold a load. Nine times out of ten it is not the whole swing assembly - this is the order to check…
Tracks weak, one side not moving
Swing, travel and drive assemblies
A travel fault looks expensive, but the checks are cheap. Work through them in this order before ordering a travel drive assembly.
Final drive noisy or metal in gear oil
Swing, travel and drive assemblies
Noise from a travel reduction gear, or metal on the drain plug, has three usual sources.
The principle behind these symptoms (4)
Reading the mechanism first usually shortens the checklist.
Closed-circuit hydrostatic drives: why travel and swing use pump control
Technical Guide
How a closed-circuit hydrostatic drive works: variable pump, motor, relief valves and charge pump; why it wastes less energy than a…
Travel and swing drives: three numbers that decide whether a hydrostatic drive lasts
Technical Guide
Charge pressure, case drain flow and control response - measured hot - tell you whether a pump-controlled drive is healthy.
Swing, travel and the four quadrants: why a motor is not a cylinder
Technical Guide
A motor is symmetric, so speed and flow behave simply - but it works in four quadrants, and in two of them the load is in charge.
Hydraulic noise: what the sound tells you, and the order to check it
Technical Guide
Fluid noise and mechanical noise sound different. Pick the frequency band, then work the checks in order: suction, settings, mounts, case…
Units we supply for this topic (6)
Catalogue-verified units whose internals are the ones described above.
M5X130CHB
12–15 t hydraulic excavator
121.6 / 129 / 129.2 cm³ (motor variants) · 34.3 MPa
M5X180CHB
20–25 t hydraulic excavator
148.5 / 169.4 / 180.1 cm³ (motor variants) · 34.3 MPa
FDNB08
5–6 t excavator
FDNB12
8–10 t excavator
FTD45
18–22 t excavator / drilling rig / crawler crane
FTD48
22–26 t excavator / drilling rig / crawler crane
Parts that solve this (6)
Catalogue part lines from the same families. Search the full library by part number from the parts library.
2933800774
DRIVE SHAFT(F) · pos. 111
2933800890
DRIVE SHAFT(F) · pos. 111
2933800982
DRIVE SHAFT(F) · pos. 111
2933801244
DRIVE SHAFT(F) · pos. 111
2943800426
DRIVE SHAFT(F) · pos. 111
2924250-0490
DRIVE SHAFT(F) · pos. 111
Machines this applies to (6)
Machine pages that list the units above as fitment, model by model. See every machine →
SANY SY135
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC140B
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
DOOSAN DH150
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
KOMATSU PC130-7
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
HYUNDAI R140
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
SANY SY215
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
Other diagnosis areas
Pump and pressure supply
Pressure, delivery, wear and the pump-engine match: the guides that start at the source of the oil.
Boom, arm and cylinder functions
The working functions: drift, creep, jerky movement and every-function-at-once complaints.
Valve and pilot control
Spools, pilot pressure, proportional solenoids and pressure transients: the control layer between lever and load.
Oil, filtration and the system as a whole
Oil condition, water and air, cleanliness, climate and the system-level decisions that follow.