A logistics warehouse reported that a Heli CPQD30 forklift's mast would "jam" (stop moving) when raising the forks above 3 meters. The operator heard a grinding noise and had to rock the lift lever to get it moving.
The technician inspected the "Mast Rails." He found the "Inner Mast Channel" was bent slightly inward on the left side. This was likely caused by a previous collision where the forks hit a racking upright. The bent rail caused the "Roller Carriage" to bind as it traveled up the rail, increasing friction.
He also checked the "Carriage Rollers." Several "Roller Pins" (the shafts holding the rollers) were loose. The locking nuts had backed off due to vibration. The loose rollers were wobbling, causing them to ride up onto the rail flange rather than rolling in the track. This wobbling caused the grinding noise.
The repair involved using a "Hydraulic Ram" to carefully straighten the inner mast rail (cold straightening). The loose roller pins were re-secured with new locking nuts and "Thread-Locking Compound" (Loctite). The entire mast rail surface was cleaned and greased. The forks then raised and lowered smoothly through the full height range without binding.
