When attaching a new set of forks to a loader equipped with a hydraulic quick-coupler, an operator connects the hydraulic lines and attempts to lock the coupler. The coupler pins extend partially but do not fully engage or lock into the attachment. Upon inspection, the operator notes a slight leak from one of the quick-coupler's hydraulic hoses at the fitting. What is the MOST likely reason for the coupler not fully engaging?

Question: When attaching a new set of forks to a loader equipped with a hydraulic quick-coupler, an operator connects the hydraulic lines and attempts to lock the coupler. The coupler pins extend partially but do not fully engage or lock into the attachment. Upon inspection, the operator notes a slight leak from one of the quick-coupler's hydraulic hoses at the fitting. What is the MOST likely reason for the coupler not fully engaging?

Answer options: ✅ Insufficient hydraulic pressure due to the leak.

• The quick-coupler pins are bent.
• The auxiliary hydraulic pump has failed.
• The attachment's mounting hooks are deformed.

Correct answer: Insufficient hydraulic pressure due to the leak.

Explanation: A hydraulic leak at the fitting indicates a loss of pressure in the quick-coupler circuit, which would prevent the hydraulic pins from fully extending and locking the attachment. While bent pins or deformed hooks could prevent engagement, a known leak directly impacts the ability of the hydraulic system to exert the necessary force for full pin extension. A failed auxiliary pump might cause no movement at all, not partial movement.