Case 680H Hose Challenges

[MikePhua]

Hose Access Insight
The Case 680H loader-backhoe, notably equipped with an extendahoe (extendable dipper arm), sometimes develops internal hydraulic hose leaks, making fluid seep into the dipper arm housing—often like a sieve. One practical workaround involves removing the top pin of the extendahoe cylinder, allowing the piston to slide partially outward and expose hose fittings for removal and replacement—without the need to detach the dipper or bucket. This creates just enough clearance to work inside the confined dipper.
Pulling the lever while holding the machine shut off can cause hydraulic fluid to spray if the lines are not capped—so caution is vital.
Machine Background and Capabilities
The Case 680H was produced in the early to mid-1980s as a robust loader-backhoe model. Weighing around 15,850 lb (7,190 kg), it packages an open-center hydraulic system with approximately 13.7 gal (52 L) reservoir and a pump flow of about 26 - 98 gpm (98 L/min), delivering relief pressure near 2,550 psi. The engine is a 4-cylinder diesel, producing roughly 80–85 hp, around 236 lb-ft of torque at 1,500 rpm.
Its backhoe arm reaches up to 20 ft, extended digging depth around 21 ft, and an operating speed near 19 mph.

Glossary of Key Terms

• Extendahoe: A telescoping backhoe arm that extends to boost reach.
  
• Dipper arm housing: The part of the backhoe that encloses the extendahoe cylinder.
  
• Top cylinder pin: Attachment pin at the top of the extendahoe cylinder.
  
• Hydraulic hose fittings: Connectors between hoses and hydraulic cylinders.
  
• Hydraulic fluid leak: Escaping fluid caused by hose wear or seal failure.
  
• Confined access workaround: Creative method to reach parts in tight spaces.
  

Step-by-Step Fix Strategy

• Remove or disengage the bucket, if needed, and support the extendahoe parallel to the ground using pallets or shims for stability.
  
• Remove the top pin or nut of the extendahoe cylinder so the cylinder barrel can slide outward a few inches.
  
• Retract and slide out the cylinder just enough to reach the hose fittings inside the dipper, then remove hoses carefully.
  
• Use caps or plugs on the hose ports to prevent fluid loss or contamination when disconnected.
  
• Install new hoses or fittings as needed, then re-seat the cylinder and reinstate the pin.
  
• Function-test the extendahoe to ensure no leaks and smooth operation.
  

Parts & Seal Kit Access
Maintenance often includes replacing seals or cylinder hoses. Suppliers such as HW Part Store offer seal kit sets for the Case 680H, covering dipper, boom, bucket, outriggers, stabilizer, and swing cylinders—often at significantly reduced cost compared to OEM, backed by pressure tests and limited warranties.

For hoses and tube assemblies, commercial hydraulic parts outlets provide SAE-standard hose kits—for instance, hoses with 6.35 mm internal diameter (SAE 100R16) and specific length (e.g., 495 mm) ready for Case machines.

Large parts distributors like AMS Parts offer a broad selection of new aftermarket, used, and rebuilt items—from hydraulic cylinders and attachments to radiators and cab components—for the 680H.

Field Anecdote
An operator in rural Connecticut faced a stubborn extendahoe leak. Instead of hauling the machine to a shop, he used the pin-removal trick, sliding out the cylinder just enough to swap the hose fitting inside his backyard. The straightforward fix avoided winching, saved hours of labor, and got the machine back into action in half a day.
Industry Context
Operators in independent service centers report that extendahoe cylinder hoses commonly fail due to pinch points inside the dipper tube. The creative removal trick, while unconventional, is frequently mentioned in service bulletins as a valid field repair method. It's efficient, avoids full assembly removal, and reduces hydraulic fluid spills and machine downtime.
Summary
For Case 680H machines with hydraulic leaks in the extendahoe, removing the top cylinder pin and sliding out the cylinder slightly offers practical access for hose replacement without full dipper removal. Key hydraulic specs—like 26 gpm pump flow and ~2,550 psi pressure—shape the replacement hose requirements. Seal kits and hoses are available affordably via aftermarket suppliers. This approach keeps the machine operational and minimizes costly disassembly.