Case 680CK Construction King Backhoe Loader: Specs, Parts & Common Issues
The launch machine of the 680 line — a larger-frame Construction King introduced in 1966 alongside the 580CK as Case's mid-size industrial loader backhoe. Case 267D diesel or 251G gasoline four-cylinder, 71 HP, power shuttle transmission, 27 gpm open-center hydraulics.
The Case 680CK is the launch machine of the 680 line, introduced in 1966 as a larger-frame industrial backhoe loader to sit above the 580CK. It carried the Construction King name, four-cylinder Case engines (267 cu in diesel or 251 cu in gas, both rated at 71 HP gross), and a power shuttle transmission with a single-stage torque converter. The 680CK ran from 1966 through 1968 in factory original form. In 1969, Case introduced the 680B as a Series B update, and the 680CK chassis effectively continued in revised form through the 680B and 680C runs.
Because the 680CK is a 60-year-old machine, factory documentation is the source of truth for restorers and operators still keeping these in service. Some online specs (including earlier versions of our own spotlight) carried over engine and hydraulic figures from the smaller 580CK family — those numbers do not match the 680CK's actual heavier-duty drivetrain. The corrections below come from the factory service literature.
At-a-glance specifications
Case 680CK — factory specifications
- Production years
- 1966 – 1968 (Series A)
- Successor
- Case 680B (1969 – 1970)
- Engine (diesel)
- Case 267D four-cylinder, liquid-cooled
- Engine (gasoline option)
- Case 251G four-cylinder, liquid-cooled
- Displacement (diesel)
- 267 cu in (4.4 L)
- Displacement (gas)
- 251 cu in (4.1 L)
- Bore × stroke (diesel)
- 4.125 in × 5.00 in (105 × 127 mm)
- Power (gross)
- 71 HP (53 kW) @ 2,000 rpm
- Power (net)
- ~64 HP (47.7 kW)
- Torque
- 215 lb-ft @ 1,300 rpm
- Transmission
- Power shuttle, hydraulic clutch, 4F / 4R, single-stage torque converter
- Drive
- 2WD
- Brakes
- Mechanical dry-disc, hand-operated parking brake
- Hydraulic system
- Open-center, gear pump
- Hydraulic flow
- ~27 gpm (102 L/min)
- System pressure
- ~1,950 psi (134 bar)
- Operating weight
- ~13,500 lb (6,123 kg)
- Loader bucket capacity
- 1.0 – 1.25 cu yd
- Backhoe dig depth
- Up to ~14 ft
- Loader breakout force
- ~8,900 lb
- Travel speed (max)
- ~19.5 mph (31 km/h)
Serial number identification
The Case 680CK serial number plate is mounted on the left side of the frame just behind the loader tower, or stamped into the bell housing area near the transmission. Approximate serial number ranges by model year:
| Year | Approximate serial range |
|---|---|
| 1966 | 9100001 – 9101500 |
| 1967 | 9101501 – 9101800 |
| 1968 | 9101801 onward (then 680B begins) |
The 680B continues the 680 serial sequence from 1969 onward, so a 680 machine with serial 9102300 or higher is almost certainly a 680B, not a 680CK. Confirm by serial plate and by engine identification before ordering parts.
How to identify the 267D engine vs. the smaller 188-class
Distinguishing the 680CK's 267D from the smaller 580CK's G188D is straightforward once you know what to look for:
- Block size — the 267D has a longer block and visibly larger cylinder head than the 188 family.
- Bore × stroke — 267D is 4.125 × 5.00 in; the 188-class is approximately 3.625 × 4.50 in.
- Oil capacity — 267D holds about 8 quarts, the 188-class holds 6 quarts.
- Injection pump — the 267D uses a larger-flow Bosch in-line pump sized for the 4.4 L displacement.
- Stamped block ID — look for "267" or "251" stamped near the block-to-bell-housing flange on the left side.
If the engine in your 680CK has been replaced and you find a 188-class block in there, that's a non-original swap — common on machines whose original 267D failed and the owner sourced whatever was available. Verify before ordering 267D-specific service parts.
Power shuttle transmission
The 680CK was offered with Case's Power Shuttle transmission — a hydraulically actuated forward/reverse clutch pack paired with a single-stage torque converter and a 4-speed mechanical gearbox. The result is four forward and four reverse speeds, with direction changes accomplished without a foot clutch using the shuttle lever on the steering column.
The power shuttle is durable but has predictable wear: the hydraulic clutch packs wear out, the shuttle control valve gets sticky, and the torque converter charge pump weakens over time. Symptoms of wear: harsh direction changes, slow reverse, or slipping under load. Service involves dropping the rear casting and inspecting the clutch packs.
Hydraulic system
The 680CK uses an open-center hydraulic system driven by a gear-type main pump. Combined flow is approximately 27 gpm at 1,950 psi — substantially higher than the smaller 580CK family. The high flow rate gives the 680CK its working speed under load: faster boom, dipper, and loader cycles than its smaller sibling at the cost of more parasitic engine load.
The L26379 hydraulic pump in our catalog is labeled for "680CK-B and 680CK-C" — that's Case's internal naming for the 680B (Series B) and 680C (Series C) updates to the 680CK platform. The pump physically interchanges across the 680CK-A (the original launch model covered here), 680B, and 680C, making it a one-part-fits-three-machines item.
Parts in stock
The 680CK has been out of production for over half a century, so service parts are limited. The handful below are confirmed available at Broken Tractor with verified 680CK fitment.
| Part # | Part | Notes |
|---|---|---|
| A34009 | Water pump | Cross-fits Case 750, 850, 1150 dozers and the 680CK backhoe — all machines that ran the 267-class Case industrial diesel. Common wear item on 60-year-old machines; replace when coolant weeps from the weep hole or the shaft develops play. |
| G14420 | Ring gear and pinion set | Differential ring gear and matched pinion for the rear end. Confirmed fit 680CK and 680B (same rear casting). Used when the rear axle has been run with low oil or the original gears have lost teeth. |
| L26379 | Main hydraulic pump | Open-center gear pump for the backhoe and loader hydraulics. Listed for 680CK Series B and Series C. The Series A original pump shares the same casting and mounting — verify by physical comparison if uncertain. |
For 680CK service literature, our parts team can help locate a factory service manual reproduction. The Case 680B / 680C service manual (CA-S-680BCTLB) covers Series B and C in detail and is often used as a reference for the closely related Series A.
Common issues on surviving machines
Engine head gasket / cylinder head cracks
The 267D head gasket and cylinder head are now well past expected service life on any original-engine machine. Pre-combustion chamber cracks, head warping after overheating events, and head gasket failures between cylinders are routine on machines that have seen any neglect. Plan on a full head rebuild as a baseline restoration step.
Power shuttle clutch wear
The hydraulic clutch packs in the power shuttle wear and the shuttle valve gets sticky. Drop the rear and replace the clutch packs as a set. The torque converter often needs attention at the same time.
Hydraulic seal hardening
Every cylinder, valve, and motor in the system has seals that are now 50-plus years old. Even on a low-hour machine, the seals will be hard and brittle. Rebuild every cylinder and the main control valve as a baseline restoration step.
Electrical system corrosion
The 680CK electrical system is simple by modern standards but the harness, connectors, and switches have all aged. Corroded battery cables, failed starter solenoids, and intermittent gauge faults are common.
Restoring a Case 680CK?
The 680CK is a rare bird — only a handful of parts cross from later 680-line machines, and most service items have to be sourced piecemeal. Our parts team can help you track down the right components by part number, fit confirmation, and serial number range.
Mon – Fri, 7:00 AM – 5:00 PM CT
Contact Broken TractorWhere it sits in the 680 family
The 680CK is the founding machine of the 680 line. After 1968, the 680B took over with refinements (1969–1970), followed by the 680C with the larger Case 301 cu in diesel (1971–1974), then the 680E, 680G, 680H, 680K, and finally the 680L closing out the larger-frame line in the 1990s. Across the line, the 680 family sat one rung above the 580 family in Case's Construction King hierarchy.
