I. Introduction: Procurement Requirements and Winning Solution By the end of 2025, a municipal sanitation department (Wuxi region) publicly tendered for one blue-license-plate sewage treatment vehicle to meet urban sewage pipeline maintenance needs. The project budget was capped at approximately RMB 337,000, requiring the vehicle to possess functions including sewage suction, solid-liquid separation, wastewater purification, and emergency drainage—while also complying with blue license plate (Class C driver’s license) operation, exemption from vehicle purchase tax, and nationwide registration eligibility. After multiple rounds of evaluation, Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as “Chengli”) won the bid with its CLW5070GSSD6 sewage treatment vehicle, modified on the Dongfeng D6 chassis, at a delivery price of approximately RMB 285,000 (based on publicly available tender information). The vehicle is built on the Dongfeng D6 National VI chassis, equipped with a full-power power take-off (PTO), a 3-cubic-meter sewage tank, a stacked-screw solid-liquid separator, a high-pressure cleaning pump, and a self-priming sewage discharge system, achieving a treatment capacity of 15–20 m³/hour. Customer feedback indicates high processing efficiency for septic tank sludge with ~30% moisture content during trial operation; three emergency cleanup sites were completed within one week, with stable performance. II. How to Draft After-Sales Clauses in the Contract: Core Commitments in Chengli’s Proposal In this procurement contract, after-sales service clauses served as a key scoring criterion during evaluation. Chengli’s proposal included the following core commitments: • Chassis Joint Warranty: Dongfeng chassis covered by nationwide 4S dealership joint warranty service, with a 2-year or 50,000-km warranty period covering critical components such as engine, transmission, and axle assemblies. • Lifetime Uppersystem Support: Chengli guarantees lifetime technical support and repair services for the vehicle’s uppersystem components (e.g., sewage tank, separator, pump-valve systems); wear-and-tear parts subject to non-human-caused damage (e.g., seals, filter screens) are replaced free of charge for one year. • Response Time Guarantee: The contract explicitly stipulates remote technical guidance within 2 hours upon receipt of a service call; on-site technician dispatch is guaranteed within 24 hours for provincial locations and within 48 hours for inter-provincial locations. • Spare Parts Availability: Chengli guarantees same-day shipment (within 24 hours) of commonly used spare parts (e.g., high-pressure pumps, solenoid valves, control cabinets) to prevent operational downtime due to parts shortages. • Training and Acceptance: Operational training is provided upon delivery—including driving, routine maintenance, and fault diagnosis—and a formal “After-Sales Service Commitment Letter” is issued as an annex to the contract. These clauses directly align with industry standards in the evaluation process; customers commented that the terms are “clearly defined, with no hidden fees.” III. Common After-Sales Disputes: Pitfalls Buyers Should Watch Out For Based on Chengli’s experience servicing over 500 municipal sanitation units, common post-purchase after-sales disputes involving sewage treatment vehicles include: • Ambiguous Responsibility Between Chassis and Uppersystem: Some manufacturers separate after-sales responsibilities for chassis and uppersystem components. In case of failures (e.g., PTO noise, electrical short circuits), both parties may shift blame. Chengli’s solution ensures “one-stop service,” combining Dongfeng chassis joint warranty with lifetime uppersystem support—eliminating finger-pointing. • Non-Transparent Spare Parts Pricing: Certain vendors omit detailed spare parts pricing from contracts, then impose inflated prices during subsequent replacements. Chengli provides a comprehensive “Spare Parts Pri