OE 251721401F — Clutch Master Cylinder for Volkswagen

OEM means the part was produced for the vehicle maker's assembly line; aftermarket means it is made independently to the same engineering drawing. For a clutch master cylinder the practical gap is usually tooling age and packaging rather than fit, provided the tolerance class matches.

Wholesale pricing for 251721401F depends on order quantity, surface treatment and packing. Standard references are quoted ex-Guangzhou with tiered pricing from 10 pieces upward — send quantity and destination port and a quotation usually returns within one business day.

Build-year coverage is listed row by row in the Applications table above. Where several generations share one number, the newer rows usually carry a revised suffix — compare the last four characters before buying, since a suffix change often means a different connector or bracket.

Report it with the order number and packing-list line plus photographs. Because every carton is photographed before loading, we can trace the batch immediately and settle the claim against the inspection record instead of arguing from memory.

The Related OE References table above lists the alternates we see most often in trade inquiries. Cross-references work because the engineering envelope is shared across the brake system family — always confirm dimensions and connector layout before you swap.

Watch for noise on cold start, vibration under load, warning lights, fluid seepage or uneven operation. Once any of those appears the clutch master cylinder should be inspected, and reference 251721401F replaced if it measures outside specification.