Case 680B Construction King Backhoe Loader: Specs, Parts & Common Issues
The Series B update to the 680CK platform, produced 1969–1970. Same Case 267D 4.4-liter four-cylinder diesel and power shuttle drivetrain as the launch 680CK, with refinements to the loader, backhoe, and hydraulic system. Sits between the 1966–1968 launch 680CK and the larger-engine 1971 680C.
The Case 680B is the Series B update to the 680CK platform. It came to market in 1969, replacing the launch 680CK, and ran through 1970 before the 680C took over with the larger 301 cu in Case diesel. Mechanically, the 680B carries forward the same Case 267D four-cylinder 4.4-liter diesel engine (71 HP gross), the same power shuttle transmission with single-stage torque converter, and the same general open-center hydraulic architecture. What changed at the Series B were detail refinements: hydraulic system improvements, loader and backhoe iron updates, and minor cab and operator-station tweaks.
Because the 680B and 680CK share so much of the powertrain, many service parts cross between the two — most notably the ring gear / pinion, the engine internals, and the main hydraulic pump. That's good news for owners maintaining a 680B today: the verified-fitment cross-references widen the available parts pool.
At-a-glance specifications
Case 680B — factory specifications
- Production years
- 1969 – 1970
- Predecessor
- Case 680CK (1966 – 1968)
- Successor
- Case 680C (1971 – 1974)
- Engine
- Case 267D four-cylinder diesel
- Displacement
- 267 cu in (4.4 L)
- Bore × stroke
- 4.125 in × 5.00 in (105 × 127 mm)
- Power (gross)
- 71 HP (52.9 kW) @ 2,000 rpm
- Power (net)
- 64 HP (47.7 kW)
- Torque
- 215 lb-ft (291.5 Nm) @ 1,300 rpm
- Cooling system capacity
- 30 qts
- Engine oil capacity
- 8 qts
- 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 psi (138 bar)
- Operating weight
- ~14,000 – 14,800 lb (6,350 – 6,713 kg)
- Loader bucket capacity
- 1.0 – 1.25 cu yd
- Backhoe dig depth
- Up to ~14 ft
- Loader breakout
- ~9,100 lb
How the 680B differs from the 680CK
The Series B refinements over the 680CK are not dramatic — this was a running update, not a platform overhaul. The notable changes:
- Hydraulic system improvements — refined pump and control valve internals, modest pressure increase from 1,950 to approximately 2,000 psi.
- Loader and backhoe iron — minor reinforcement updates to the loader arms and backhoe boom for improved lift and dig performance.
- Operator station — small refinements to control linkages and the operator seat.
- Operating weight — slight increase (~1,000 lb over the 680CK) reflecting the iron updates.
The engine, transmission, axles, and main hydraulic pump are largely unchanged from the 680CK — and that's reflected in the verified parts cross-fit. Items like the G14420 ring and pinion set are explicitly listed as 680CK / 680B fitment, and the L26379 main hydraulic pump carries the 680CK-B (Series B = 680B) designation.
Why "680CK-B" appears in part labels
Case's internal nomenclature for the 680 series used letter suffixes to denote the generation: 680CK Series A = the original 680CK launch model (1966–1968), 680CK Series B = the 680B (1969–1970), 680CK Series C = the 680C (1971–1974). Many factory parts catalogs and service manuals carry these "680CK-B" and "680CK-C" labels for parts that physically cross those generations. That's why our L26379 hydraulic pump listing reads "680CK-B, 680CK-C" — it covers the 680B and the 680C, and almost certainly the 680CK Series A as well by physical interchange.
If you're shopping for parts and see the "680CK-B" callout, treat it as covering the 680B. The G14420 ring and pinion explicitly listed as "680CK, 680B" is a clearer naming convention applied to the same underlying cross-fit logic.
Power shuttle service
The Case Power Shuttle on the 680B has the same architecture and wear pattern as the 680CK before it and the 680C after it. The hydraulically actuated forward/reverse clutch packs are the primary wear item, and the torque converter charge pump weakens with age. Symptoms of wear:
- Harsh direction changes — clutch packs worn or shuttle valve sticky.
- Slow or weak reverse engagement — clutch pack worn on the reverse side.
- Engine bogging on direction change — torque converter losing efficiency, often paired with low charge-pump pressure.
- Whining noise from the rear under load — pump cavitation or charge-pump failure.
Service involves dropping the rear casting, inspecting and replacing the clutch packs as a matched set, and checking the torque converter for damage. The Case 680B / 680C service manual (CA-S-680BCTLB) documents the procedure step-by-step.
Parts we carry
The 680B is over 55 years old at this point, so service parts are limited. The items below are available at Broken Tractor with verified 680B fitment.
| Part # | Part | Notes |
|---|---|---|
| G14420 | Ring gear and pinion set | Differential ring and pinion for the rear end. Explicit cross-fit 680CK and 680B (same rear casting). Used when the rear axle has been run with low oil, contaminated fluid, or the original gears have lost teeth. |
| L26379 | Main hydraulic pump | Open-center gear pump for the backhoe and loader. Labeled "680CK-B, 680CK-C" — Case's factory naming for the 680B and 680C. Same pump physically used on all three Series A / B / C 680CK machines. |
| CA-S-680BCTLB | Service manual (836 pages) | Factory Case service manual covering the 680B and 680C. The single most useful reference document for anyone working on a 680B. Covers engine, drivetrain, hydraulics, brakes, and electrical in depth. |
| D30899 | Trenching bucket pin (12-in buckets) | Bucket-to-stick pin for 12-inch trenching buckets. Cross-fits Case 580 series and 680B backhoe buckets that use this pin size. |
For broader 680B parts work, the engine is the same Case 267D used on the 680CK, the 750 / 850 / 1150 dozers, and certain other Case industrial machines from the era. Parts called out as 267D fitment will generally apply.
Common issues and what to expect
Engine head and cylinder head gasket
Same as the 680CK — any 267D engine left in original-factory condition will have age-related head wear. Cracks at the pre-combustion chambers, head gasket failures between cylinders, and warping from past overheating are all expected. Plan on a full top-end rebuild as a baseline restoration step on any unrestored 680B.
Power shuttle wear
Outlined in the section above. The hydraulic clutch packs and torque converter charge pump are the routine wear items.
Hydraulic cylinder seal failure
Every cylinder on a 680B has seals that are 55-plus years old. Even a low-hour machine will need every cylinder rebuilt as a baseline restoration step. The good news: bores are typically still good, so reseal kits are usually sufficient.
Loader and backhoe pin/bushing wear
The boom-to-frame, swing tower, dipper, and bucket pins all wear with use. Sloppy operation, dropped loads, or unusual cycle behavior under load are signs that the pins and bushings need attention. Replacement is straightforward but time-consuming.
Working on a Case 680B?
The 680B service manual (CA-S-680BCTLB) is the single most useful reference for these machines. Beyond that, the parts cross-fit with the 680CK and 680C widens what's available. Our specialists can verify fitment by serial number and physical comparison before you order.
Mon – Fri, 7:00 AM – 5:00 PM CT
Contact Broken TractorWhere it sits in the 680 family
The 680B is the middle of the three Construction King-naming-era 680 machines (680CK Series A, B, C). After the 680C in 1974, Case revised the model designation to drop the CK prefix entirely and moved through 680E, 680G, 680H, 680K, and 680L over the following two decades. The 680 family always sat one frame size above the 580 family in Case's lineup.
