Case 680C Construction King Backhoe Loader: Specs, Parts & Common Issues
The Series C update introduced 1971 and the first 680 to step up to the larger Case 301D 4.9-liter four-cylinder diesel — 74 HP, more torque, and meaningful gains in dig and lift performance over the 267-class predecessors. Same power shuttle drivetrain and open-center hydraulics as the 680B, with the bigger engine doing the heavy lifting.
The Case 680C is the third generation of the 680CK platform — the Series C in Case's internal nomenclature. It came to market in 1971, replacing the 680B, and ran through 1974 before the 680E took over the larger-frame Construction King slot. The defining change at the Series C was the engine: Case stepped up from the 267 cu in 4.4 L 267D used on the 680CK and 680B to the larger 301 cu in 4.9 L 301D — a meaningful displacement increase that bumped output to 74 HP and gave the 680C noticeably stronger torque under load.
Outside the engine swap, the 680C retains the same general chassis, the same Case Power Shuttle transmission with single-stage torque converter, and the same open-center hydraulic architecture as the 680B. Most non-engine service parts cross between the 680B and 680C — most notably the main hydraulic pump (L26379, explicitly labeled "680CK-B, 680CK-C"), the ring and pinion, and the service manual itself (CA-S-680BCTLB), which covers both models in a single 836-page reference.
At-a-glance specifications
Case 680C — factory specifications
- Production years
- 1971 – 1974
- Predecessor
- Case 680B (1969 – 1970)
- Successor
- Case 680E (~1974/75 onward)
- Engine
- Case 301D four-cylinder diesel
- Displacement
- 301 cu in (4.9 L)
- Cylinders
- 4, liquid-cooled, direct-injection diesel
- Power
- 74 HP (55.2 kW) @ 2,000 rpm
- Peak torque
- ~220 lb-ft @ ~1,400 – 1,600 rpm
- Fuel tank capacity
- 28 gal (106 L)
- Transmission
- Power shuttle, 4F / 4R, single-stage torque converter
- Drive
- 2WD
- Brakes
- Mechanical dry-disc
- Hydraulic system
- Open-center, gear pump
- Hydraulic flow
- ~27 gpm (102 L/min)
- System pressure
- ~2,000 – 2,200 psi
- Operating weight
- ~14,700 lb (6,667 kg)
- Length
- ~267 in (678 cm)
- Width
- ~82 in (208 cm)
- Wheelbase
- ~80.5 in (204 cm)
- Backhoe dig depth
- Up to ~14 ft
The 267D → 301D engine step
The Case 301D is the larger sibling of the 267D used on the 680CK and 680B. Both are four-cylinder, liquid-cooled, direct-injection diesels in the same general Case industrial-engine family. The 301D appears on the 680C and continues onto a number of Case industrial machines through the mid-1970s. Key identification points for the 301D vs. the 267D:
- Stamped block ID — "301" stamped on the left side of the block near the bell housing flange. The 267D will have "267" in the same spot.
- Displacement and bore-stroke — 301D is 301 cu in (4.9 L), the 267D is 267 cu in (4.4 L). The 301D block is taller or wider depending on whether Case used a stroke or bore increase to grow the displacement.
- Injection pump — both use Bosch in-line injection pumps, but the 301D pump is calibrated for higher fuel flow.
- Power rating — 301D is 74 HP, 267D is 71 HP. The torque rating is where the bigger engine really pulls ahead.
If you're verifying an original 680C engine, look for the "301" block stamp first. Engine swaps are common on these machines — a 680C with a 267D dropped in to replace a failed 301D will work mechanically but will not perform like the factory 301D-equipped machine and will need different parts ordered for engine internals.
Power shuttle and drivetrain
The 680C uses the same Case Power Shuttle transmission as the 680CK and 680B: four forward and four reverse speeds, hydraulically actuated clutch packs for direction changes, single-stage torque converter, no foot clutch. The factory service manual (CA-S-680BCTLB) covers the power shuttle in depth and is the reference document any restorer should have on hand.
Service items on the power shuttle are predictable: clutch packs wear, the shuttle control valve gets sticky over time, and the torque converter charge pump weakens. The good news is that all 680CK / 680B / 680C drivetrain parts cross between the three machines, so available parts pools are larger than the 680C alone would suggest.
Hydraulic system
Open-center, gear-pump hydraulics carry forward from the 680B unchanged in architecture. Combined flow is approximately 27 gpm. Working pressure is in the 2,000–2,200 psi range. The L26379 main hydraulic pump in our catalog is the verified replacement for the 680B and 680C — and physically interchanges to the 680CK as well.
Parts we carry
The 680C is over 50 years old. Available service parts are limited and largely cross-fit with the 680B. The items below are available at Broken Tractor with verified 680C fitment.
| Part # | Part | Notes |
|---|---|---|
| L26379 | Main hydraulic pump | Open-center gear pump for the backhoe and loader. Explicitly labeled "680CK-B, 680CK-C" — Case's internal naming for the 680B and 680C. Same pump physically interchanges across the three 680CK-platform machines. |
| G14420 | Ring gear and pinion set | Differential ring and pinion. Labeled for 680CK and 680B but physically cross-fits the 680C (same rear casting and gear specification across the three machines). Used when the rear axle has lost teeth or been run with low oil. |
| CA-S-680BCTLB | Service manual (836 pages) | Factory Case service manual covering the 680B and 680C. The 301D-specific engine sections are in this manual — the most authoritative reference for any 680C restoration or major repair. |
For engine-specific parts, the 301D engine is shared with several Case industrial machines of the same era. Items called out as 301D fitment will generally apply — water pumps, oil pumps, gasket sets, and some bearing sets cross to other 301D applications.
Common issues and what to expect
301D engine head and gasket wear
Same age-related issues as the 267D on earlier 680s. Pre-combustion chamber cracks, head gasket failures between cylinders, and warping from past overheating events are all expected. A full top-end rebuild is a baseline restoration step on any unrestored 680C. Confirm the engine is original-fitment 301D before ordering 301D-specific head parts.
Power shuttle clutch pack wear
Same as the 680CK and 680B. Harsh direction changes, slow reverse engagement, and engine bogging on direction change all point to clutch pack wear or torque converter weakness. Drop the rear casting and inspect.
Hydraulic cylinder seal failure
Every cylinder on a 680C has seals that are at least 50 years old. Plan on rebuilding every cylinder as part of any restoration. Bores are typically still good — most cylinders only need reseal kits, not new bodies.
Fuel system contamination
50-year-old fuel tanks have rust, varnish, and water contamination buildup. Symptoms: hard starting, rough running, smoking under load. Drain and clean the tank, replace fuel lines, and rebuild or replace the injection pump and injectors as needed.
Electrical and gauge cluster faults
The original wiring harness is now well past expected service life. Corroded connectors, failed switches, and intermittent gauge faults are routine. Many restorations end up with a completely new harness.
Restoring or maintaining a Case 680C?
The 301D engine swap is the defining 680C feature — make sure you're working with the correct engine block before ordering parts. Our specialists can verify by stamp ID and physical comparison, and cross-reference 680B fitment items that interchange to the 680C.
Mon – Fri, 7:00 AM – 5:00 PM CT
Contact Broken TractorWhere it sits in the 680 family
The 680C closes out the original 680CK Construction King platform that ran from 1966 through 1974. After the 680C came the 680E in the mid-1970s — a more substantial platform update with Case's industrial cab, updated hydraulics, and continued use of the 301-class engine. From there the 680 line stepped through G, H, K, and L generations into the 1990s before being retired in favor of the larger 590-line Super N as Case's biggest backhoe loader.
