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The 6N0412303A strut bump stop is a suspension buffer that fits Seat and Volkswagen models built on the small-platform front and rear strut layouts. This part sits on the piston rod of the shock absorber and works as a progressive jounce bumper: it limits suspension travel on compression, absorbs impact energy before the damper bottoms out, and protects the strut mount, the coil spring and the body from metal-to-metal contact. Importers, repair chains and wholesale distributors usually source this item by the OE number together with a measured size check, because several platform variants look almost identical on the shelf.
| Item | Specification |
|---|---|
| Product Name | Strut Bump Stop |
| OE Number | 6N0412303A |
| Bonpora Nos | 4110016 |
| Fitment | Seat / Volkswagen |
| Size | Φ20.5 mm x Φ61 mm x 65.5 mm (inner bore x base outer diameter x free height) |
| Material | Polyurethane (PU) |
| Country of Origin | China |
| Warranty | 1 Year |
| Delivery Time | 15-30 Days |
| Packaging | Neutral Export Packaging |
| Custom Service | OEM & Custom Design Support |
Vehicle names are unreliable across markets. A platform sold as a Volkswagen in one country is often badged as a Seat or a Skoda in another, and the same showroom name can span three different suspension generations. The OE number 6N0412303A removes that ambiguity: it is a unique engineering identifier for one physical buffer with a defined bore, base diameter, free height and rubber-to-metal bond. Professional buyers treat the OE code as the first filter and the dimensions as the second.
In the Volkswagen Group numbering system, the leading group identifies the platform family and the middle four digits (412 303) identify the function, which in this case is a front or rear strut buffer in the suspension group 412. The trailing letter is a revision index: a part without a letter, with an A, or with a later letter can differ in height, hardness or compound. That is why a quote request should always include the full number including the revision letter rather than the base number alone.
Many factory strut bump stops use cellular foam or a soft microcellular rubber. These materials give a comfortable first contact, but they degrade faster: they crumble, take on water, or collapse permanently after repeated full compression, which is exactly the condition seen on older Seat and Volkswagen cars. Polyurethane is a cast elastomer. It keeps its shape under cyclic loading, resists oils, road salt and ozone, and can be formulated across a wide hardness range, so a supplier can tune the compression curve to a target vehicle instead of copying one generic block.
| Property | Polyurethane (this part) | OEM foam / soft rubber |
|---|---|---|
| Compression set after repeated cycling | Low, recovers shape | Higher, can crush permanently |
| Oil and ozone resistance | Good | Moderate |
| Hardness tuning | Wide range available | Limited |
| Service life in mixed climates | Longer | Shorter, tends to crumble |
If you also buy other suspension buffers, the full range of polyurethane bump stops covers several platform families in the same material grade, which lets you consolidate a mixed order.
Bump stops rarely fail alone. When the buffer collapses, the strut travels further than designed and neighbouring parts start to take the load. Warning signs reported by workshops include:
Because these symptoms overlap with worn dampers, a replacement should be confirmed by checking the shock absorber parts as a system rather than replacing the buffer in isolation.
The part is produced in China and shipped under neutral export packaging, so the carton carries no aftermarket brand and can be relabelled for your own programme. Standard production lead time is 15-30 days depending on order volume and whether tooling already exists. A 1-year warranty applies to the supplied buffer under normal installation and service conditions.
Buyers who need a private-label buffer, a different hardness grade, a modified flange, or a part that no longer appears in any catalogue can use the custom parts service. Production starts from a drawing or a physical sample: we measure the sample, confirm the compression curve, produce a tooling sample for fitment approval, and only then move to batch production. This route is common for older Seat and Volkswagen platforms where the original foam buffer is discontinued but the vehicle fleet is still large enough to justify a run.
Each batch is inspected on three points. First, dimensional inspection of the bore, base diameter and free height against the approved sample. Second, visual inspection for flash, voids, cracks and uneven bonding. Third, a compression and rebound check on a sampled basis to confirm the hardness grade and that the buffer returns to its free height without permanent set. Batch records are kept so a shipment can be traced back to its production lot.
No. The number identifies one buffer design used across a defined group of small-platform strut layouts. Because badge engineering spreads the same platform across Seat, Volkswagen and other group brands, the correct approach is to confirm the OE number against your parts catalogue and then verify the bore, base diameter and free height against the part you are replacing. A vehicle name alone is not sufficient confirmation.
Yes, and this is a common upgrade. The bore and the mounting geometry must match, but the material can differ, and polyurethane typically lasts longer than the foam it replaces. Select the hardness grade that suits the vehicle weight and how the car is used; for heavy loads or frequent full compression, a firmer grade is usually specified.
Minimum order quantity depends on whether the part is already in production or needs new tooling. For an existing reference such as 4110016 the entry quantity is lower; for a new custom buffer, tooling and a sample approval stage apply first. Share your target annual volume and we will confirm the practical MOQ for your case.
Standard packing is neutral export carton, suitable for container consolidation and for relabelling under your own brand. Inner packing can be adjusted on request, and mixed references can be combined in one shipment if the order is planned in advance.
Send the full OE number, your measured dimensions and the target model year, and we will confirm availability, hardness grade, packaging and lead time. Samples can be arranged before a production order so your workshop can verify fitment on a real vehicle.
