Part of the Hyundai Repair Manuals.
Wrenching on an R320 excavator? This 516-page Hyundai R320LC-7A, R320NLC-7A shop manual PDF covers the LC, NLC, and NLC High Walker variants from safety hints all the way to component mounting torque. You get full hydraulic circuit schematics tracing main and pilot flow through the pump, main control valve, swing, and travel devices, plus electrical wiring diagrams with connector pinouts and component specifications. Inside: self-diagnostic error codes for the mechatronics system, a full troubleshooting section, and step-by-step disassembly procedures for cylinders, turning joint, and undercarriage. Fill the hydraulic system to 320 L, and set the pilot relief valve at 35 kgf/cm2 before you blame the pump. No more chasing pressure faults with a gauge and a guess. Bookmarked, text-searchable, and readable on any device; download it, walk to the machine, and get to work.
What's Inside This Hyundai R320LC-7A, R320NLC-7A, R320NLC-7A HIGH WALKER Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 1-41 | Safety Hints, Specifications |
| Structure and Function | 42-121 | Pump Device, Main Control Valve, Swing Device, Travel Device, Rcv Lever, Rcv Pedal |
| Hydraulic System | 122-153 | Hydraulic Circuit, Main Circuit, Pilot Circuit |
| Electrical System | 154-202 | Component Location, Electrical Circuit, Electrical Component Specification |
| Mechatronics System | 203-256 | Outline, Mode Selection System, Self-Diagnostic System |
| Maintenance Standard | 307-341 | Operational Performance Test, Major Components, Track and Work Equipment |
| Disassembly and Assembly | 342-493 | Precaution, Tightening Torque, Pump Device, Main Control Valve, Swing Device, Travel Device, Rcv Lever, Turning Joint |
| Component Mounting Torque | 494-516 | Introduction Guide, Engine System, Electric System, Undercarriage, Structure, Work Equipment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Hydraulic tank capacity | 210 L (55.5 U.S. gal) | p. 41 |
| Hydraulic system capacity | 320 L (84.5 U.S. gal) | p. 39 |
| Battery | 2 x 12V x 160Ah | p. 34 |
| bypass relief valve opening pressure | 1.5kgf/cm2 | p. 125 |
| pilot circuit relief valve pressure | 35kgf/cm2 | p. 127 |
| Voltage | 10~12.5V | p. 157 |
| Pressure switch (Travel, working) operating pressure | 10kgf/cm2 | p. 174 |
| Cassette radio voltage | 20-25V | p. 179 |
| Washer pump contact resistance | 10.7Ω | p. 179 |
| Swing motor mounting bolt torque | 58.4 ± 6.4 kgf·m | p. 345 |
| Socket head bolt (Bucket cylinder, Item 22, M18) | 32.0±3.0 kgf·m (232±21.7 lbf·ft) | p. 470 |
| Socket head bolt (Boom cylinder, Item 22, M20) | 46.5±5.0 kgf·m (336±36.2 lbf·ft) | p. 470 |
Hyundai R320LC-7A, R320NLC-7A, R320NLC-7A HIGH WALKER Common Problems This Manual Covers
Hyundai R320LC-7A boom or arm creeps down under load, dig functions drift when holding position
Check whether drift follows the cylinder or the control valve: curl the bucket, hold it, then crack the rod-side line over a drain pan. Steady flow means failed piston seals. Reseal the cylinder, then torque the piston to 150±15.0 kgf·m and the M70 lock nut to 100±10.0 kgf·m per the chart on page 470.
Manual Section: Attachment System Troubleshooting p. 470All hydraulic functions turn slow and weak after warm-up, boom and bucket feel sluggish
Check tank level first; the system holds 320 L (84.5 U.S. gal) and a low tank cavitates both pumps. Pull the return filter and inspect for metal; a plugged element bypasses dirty oil once it hits the 1.5 kgf/cm2 relief pressure shown on page 125. Verify main relief reaches 330 kgf/cm2 before tearing into the pump.
Manual Section: Hydraulic System Troubleshooting p. 125Engine cranks slowly or will not start, starter clicks with everything else working
Load-test both batteries; this machine runs 2 x 12V x 160Ah, and one weak battery drags cranking speed down. Clean and tighten the ground straps, then measure starter contact resistance; anything above the 0.1 ohm spec on page 180 means burned contacts. Check the fusible link for continuity, 0 ohms, before condemning the starter.
Manual Section: Engine Starting Troubleshooting p. 180Hydraulic oil overheats during normal digging, temperature gauge climbs into the red
Verify oil level and condition before blaming the cooler; cloudy oil means water or aeration. Blow out the oil cooler fins from the back side with compressed air. Test the hydraulic temperature sender; resistance should read 130-150 ohms per page 287. Confirm the main relief is not stuck high; standard setting is 330 kgf/cm2, power boost 360 kgf/cm2.
Manual Section: Hydraulic System Troubleshooting p. 287Machine curves to one side while traveling, travel speed falls on one track
Check track tension on both sides first; uneven tension curves the machine before hydraulics ever do. Swap the travel lines at the turning joint to isolate pump from motor. Test travel relief pressure on each circuit; both sides should hit the 330 kgf/cm2 spec on page 38. Overhaul the travel motor on the low side.
Manual Section: Travel System Troubleshooting p. 38Frequently Asked Questions
How do I clear or reset the recorded error codes on a Hyundai R320NLC-7A?
To delete all recorded error codes, select the recorded error (TIME Er) display on the cluster. Press the engine and select switch at the same time for 2 seconds or more. The cluster display will change to 'TIME Er : 00', indicating that the CPU controller has deleted all recorded error codes from the memory. p. 214
What is the tightening torque for the swing motor mounting bolts on the R320LC-7A?
The tightening torque for the swing motor mounting bolts (M20 x 2.5) is 58.4 ± 6.4 kgf·m (422 ± 46.3 lbf·ft). p. 345
What is the hydraulic tank capacity for the R320LC-7A?
The hydraulic tank capacity for the R320LC-7A is 210 liters (55.5 U.S. gal). p. 43
What is the standard tightening torque for the main relief valve on the main control valve?
The standard tightening torque for the main relief valve on the main control valve is 7 to 8 kgf·m (50.6 to 57.8 lbf·ft). p. 382
What is the standard engine speed for the R320LC-7A in M mode?
The standard engine speed for the R320LC-7A in M mode is 1800 ± 50 rpm. p. 311
Do I get instant access to this Hyundai R320LC-7A Shop Manual?
You get a 516-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Are there any print restrictions on this Hyundai R320LC-7A manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
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