Part of the Hyundai Repair Manuals.
Every one of the 532 pages in this Hyundai HL770-7 service manual PDF covers the wheel loader itself: power train, brakes, steering, work equipment, and the full electrical system. You get factory wiring diagrams with connector locations and pinouts, hydraulic schematics tracing every circuit, and error code charts for the monitoring system. Page after page of disassembly and assembly procedures walk you through each system, from torque converter to boom cylinder. Torque the six engine mounting bolts to 100 ± 15 kgf·m and set the converter back pressure valve at 3.5 bar; the numbers are right there in the tables. No more chasing electrical gremlins with a test light and a hunch. Bookmarked and text-searchable, so you can jump straight to any spec from your phone or tablet and get the loader back on the pile.
What's Inside This Hyundai HL770-7 Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 11-35 | Safety Hints, Specifications, Operational Checkout Record Sheet |
| Engine | 36-40 | Structure and Function |
| Power Train System | 41-237 | Power Train Component Overview, Torque Converter, Transmission Layout and Installation, Electro-Hydraulic Shift Control, Operating Modes, Electronic Control Unit, Transmission Disassembly and Assembly |
| Brake System | 238-277 | Brake Hydraulic Circuit, Service Brake Operation, Parking Brake Operation, Brake Valve, Principle of Operation, Brake Tests and Adjustments |
| Steering System | 278-377 | Steering Hydraulic Circuit, Steering Unit, Flow Amplifier, Neutral, Left Turn and Right Turn Operation, Steering Tests and Adjustments |
| Work Equipment | 378-459 | Hydraulic System Outline, Work Equipment Hydraulic Circuit, Main Pump Operation, RCV Lever Positions (Raise, Lower, Float, Dump, Roll, Hold), Cylinder Drift and Cycle Time Tests |
| Electrical System | 460-532 | Component Location, Electrical Circuit, Monitoring System, Electrical Component Specification, Connectors, Troubleshooting |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Engine mounting bolt(6EA) | 100 ± 15 kgf·m | p. 30 |
| Engine mounting bolt(Bracket, rear 8EA) | 10.7 ± 2.1 kgf·m | p. 30 |
| System pressure valve | 16+2 bar | p. 41 |
| Pump | 16+2 bar | p. 41 |
| Converter back pressure valve opening pressure | 3.5 bar | p. 56 |
| System pressure valve maximum control pressure | 16+2 bar | p. 57 |
| Return filter bypass valve set pressure | 1.36kg/cm2 (19.3psi) | p. 406 |
| Accumulator charging pressure of gas | 16kg/cm2 (228psi) | p. 408 |
| Accumulator max actuating pressure | 128kg/cm2 (1820psi) | p. 408 |
| Hydraulic oil filter replacement interval | 250 operating hours | p. 435 |
| Engine Oil Quantity | 20 L | p. 26 |
| Main Relief Valve Pressure | 210 kgf/cm2 | p. 27 |
Hyundai HL770-7 Common Problems This Manual Covers
Hyundai HL770-7 hydraulic pump whining loud, bucket and boom slow to respond under load
Check hydraulic oil level and inspect the suction line for pinched hoses or loose clamps. Time a full boom raise; the spec on page 434 is 6.2 seconds. If slow, replace the return filter, due every 250 hours regardless, and test main relief pressure against the 210 kgf/cm2 setting.
Manual Section: Work Equipment Troubleshooting p. 434Hydraulic oil looks milky and foamy, pump growls louder as the oil warms up
Drain a sample and look for cloudy oil; that means air is getting in. Tighten suction fittings and replace O-rings at the pump inlet. Check the return filter bypass valve, set at 1.36 kg/cm2 (19.3 psi) per page 406; a plugged element forces unfiltered, aerated oil back to tank.
Manual Section: Work Equipment Troubleshooting p. 406Steering wheel turns but loader responds slowly or not at all when engine is hot
Check hydraulic oil level first, then time a full lock-to-lock turn; the spec on page 434 is 3.0 seconds for a full frame stop-to-stop turn (4.5 turns). If steering stays slow, inspect the suction line for restriction before condemning the steering unit. When resealing it, torque the steering unit mounting bolts to 6.9 plus or minus 1.4 kgf-m.
Manual Section: Steering System p. 434No 3rd or 4th gear, transmission shifts fine through first and second
Check the cluster for stored codes against the error code reference, then trace the shift solenoid circuits with the wiring diagram. Run a stall test in first gear; 2050 rpm is the spec on page 108. Low stall speed points to converter or clutch trouble, not electrical.
Manual Section: Transmission Troubleshooting p. 108Boom drifts down overnight and bucket rolls forward slowly with the engine off
Measure boom cylinder drift against the 40 mm limit on page 429. If it exceeds spec, inspect the main control valve spools for scoring and replace worn cylinder piston seals. Reinstall the control valve with mounting bolts torqued to 12.8 plus or minus 3.0 kgf-m and retest before returning the machine to work.
Manual Section: Work Equipment p. 429Frequently Asked Questions
What is the procedure to clear transmission fault codes on the Hyundai HL770-7?
To clear transmission fault codes, you must restart the Transmission Control Unit (TCU) by turning the ignition off and then on again after the fault condition has been corrected. For specific fault codes, refer to the troubleshooting tables starting on page 492. p. 492
What is the replacement interval for the hydraulic oil filter in the hydraulic oil tank?
The hydraulic oil filter in the filter case of the hydraulic oil tank should be replaced every 250 operating hours, or more often in dirty conditions. Page 435 also warns that if metal particles or foreign matter reach the circuit you must drain the hydraulic oil, flush the system and clean the tank rather than just swapping the element. p. 435
What is the tightening torque for the main control valve mounting bolts?
The tightening torque for the main control valve mounting bolts (size M12 x 1.75) is 12.8 ± 3.0 kgf·m (92.6 ± 21.7 lbf·ft). p. 29
What is the correct oil capacity for the engine oil pan?
The engine oil pan has a capacity of 20 liters (5.3 U.S. gallons). p. 26
What is the standard value for the boom cylinder drift test?
During the boom cylinder drift test, the boom cylinder must drift less than 40mm over the specified 15-minute measurement period. p. 429
Is this Hyundai HL770-7 manual a download or a disc?
Immediate download of the complete 532-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Are there any print restrictions on this Hyundai HL770-7 manual?
Yes, printing is unrestricted: a single page, a chapter, or the lot, on letter or A4.
Reviews
There are no reviews yet.