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Strut bump stop 1K0511353P is a polyurethane suspension cushion manufactured in China by Bonpora and supplied worldwide under factory-direct terms. The part carries Bonpora reference 4110023 and corresponds to Volkswagen OE numbers 1K0511353P and 1K0511353. This page explains how the bump stop works inside a MacPherson strut assembly, publishes the technical data for the reference, clarifies the relationship between the two OE number forms, and sets out the wholesale, OEM, packaging and warranty conditions offered directly by the moulding factory. Distributors, importers and workshop groups can use the information to prepare an accurate first inquiry.
The strut bump stop - also known as a jounce bumper, bump stopper or auxiliary spring - is the progressive elastomer component fitted around the piston rod of a MacPherson strut. It comes into play during the last stage of suspension travel: when a wheel drops into a pothole, crosses a sharp ridge or the vehicle carries a heavy load, the coil spring alone cannot absorb the remaining stroke, and the bump stop compresses to cushion the impact. Without a serviceable stop, the damper bottoms out metal to metal, sending sharp shocks into the body structure and accelerating wear on the strut, its top mount and adjacent chassis parts.
On the front axle the bump stop slides over the damper rod between the top mount and the dust boot, and on some platforms it is moulded together with the dust cover as one unit. The 1K0511353P reference follows the original geometry: a 14.5 mm bore seats on the strut rod, the 79.8 mm outer diameter forms the contact face inside the housing, and the 134.6 mm free height sets the point at which the progressive section engages. The comparatively tall body of this reference is typical of stops that combine a long progressive stroke with a wide seating diameter, so buyers switching between related variants should confirm all three dimensions before ordering rather than judging by appearance alone.
Polyurethane bump stops degrade gradually rather than suddenly. Typical workshop indicators include knocking or thudding from the suspension over sharp impacts, a noticeably harsher ride at full compression, and visible cracking, powdering or permanent flattening once the strut is dismantled for service. Because the part is hidden inside the assembly, most workshops inspect or renew it whenever a strut, top mount or dust boot is already being replaced. Fitting a new stop is a low-cost safeguard compared with the cost of a damper damaged by repeated bottoming, and replacing stops in pairs on the same axle keeps handling balanced between the left and right sides.
The published parameters for Bonpora reference 4110023 are listed below.
| Parameter | Value |
|---|---|
| Product Name | Strut Bump Stop |
| OE Numbers | 1K0511353P / 1K0511353 |
| Bonpora Nos | 4110023 |
| Fitment | Volkswagen |
| Size | Φ14.5 × Φ79.8 × 134.6 mm |
| Material | Polyurethane (micro-cellular) |
| Country of Origin | China |
| Warranty | 1 year |
| Delivery Time | 15-30 days |
| Packaging | Neutral export packaging |
| Custom Service | OEM & custom design support |
The assignment lists both 1K0511353P and the shorter form 1K0511353. In Volkswagen practice, a suffix letter such as P marks a revision of a base number: the base reference identifies the general design, while suffixed versions identify updated production states issued during the life of the platform. Supersessions of this kind are common on high-volume chassis parts, and parts catalogues often cross-list the variants because the service numbers overlap. For ordering purposes the practical approach is simple: quote the complete number found on the original component, including any suffix, and add the three measurements. The Bonpora engineering team then confirms whether the inquiry matches reference 4110023 or requires a different variant from the same family.
The 1K0 prefix belongs to the numbering scheme Volkswagen applied to one of its most widely produced compact platform generations, and references in this series are commonly associated with Golf and Jetta model lines of that era as well as related models built on the same chassis family. Because the platform covered several body styles and market names, and because chassis components were revised during the production run, fitment should always be confirmed with the complete OE number printed or moulded on the original part, or through a parts-catalogue lookup, before an order is placed. If the number on the sample differs in a prefix or suffix, send it together with the measured dimensions so the correct reference can be verified before production is scheduled.
Many buyers search suspension elastomer parts not by vehicle model but by part type and measurements - for example a strut bump stop with a 14.5 mm bore and a 79.8 mm outer diameter, or a polyurethane stop of a specific free height close to 135 mm. Specification-based sourcing works well for bump stops because the three dimensions largely determine whether a part will seat and engage correctly. Measure the inner diameter, outer diameter and free height of the removed component, note the material, and compare the values with the catalogue data. The polyurethane bump stop catalogue lists references with their dimensions and OE numbers, so a spec-based cross-check is straightforward before an inquiry is sent.
OE-number sourcing remains the most reliable route for imported replacement parts, because part numbers are specific while vehicle descriptions are not. The following workflow keeps an inquiry efficient and lowers the risk of mismatched stock.
Provide the full OE number together with the inner diameter, outer diameter and free height of the old part. For this reference the expected values are approximately 14.5 mm, 79.8 mm and 134.6 mm. When all three agree, the stop will seat on the rod and engage at the intended point of the travel.
Micro-cellular polyurethane is the prevailing material for current-generation bump stops because it offers a progressive compression curve and low permanent set. Buyers converting from an original rubber stop may notice a slightly different stiffness feel; sharing the Shore hardness and free height of a reference sample allows the factory to tune the formulation to the application.
For first-time cooperation, dimensional inspection and material verification on samples are the most practical risk controls. Bonpora supports sample approval ahead of batch production, and volume supply runs under IATF 16949-based process control, so inspection records can accompany shipment documents when required.
Factory-direct purchasing removes intermediary margins and gives buyers visibility over the factors that decide batch consistency: tooling condition, material batching and process parameters. Bonpora moulds the shock absorber parts range in-house, from rubber and polyurethane compounding through to finished-component testing, which means dimension reports can be produced per batch and mould maintenance is scheduled internally rather than outsourced. Direct supply also simplifies commercial matters for wholesale buyers: volume pricing by order quantity, repeat-order scheduling against stock levels, and neutral export packaging that leaves goods unbranded for re-packing under the distributor label. For importers building a Volkswagen suspension programme across several OE references, one factory covering multiple part families reduces the number of suppliers to qualify and audit.
Beyond catalogue references, the factory develops bump stops and related custom parts from customer drawings, 3D data or physical samples. A typical project covers dimension confirmation, material formulation, hardness matching, pilot moulding and sample approval before mass production begins. Custom service also extends to colour, branding and packaging, which suits importers establishing their own ranges as well as fleet programmes that require batch documentation with every delivery.
Standard shipments use neutral export packaging labelled with the Bonpora number 4110023 for traceability, leaving the goods unbranded for distributor re-packing at destination. Delivery time is 15-30 days depending on order quantity and the production schedule, and a 1-year warranty applies to manufacturing defects. Batch traceability information is provided with each shipment, so any delivery can be matched back to production records if a quality question arises during the warranty period.
To obtain wholesale pricing for the 1K0511353P strut bump stop, send the OE number, target quantity and destination port through the contact form on this site. A standard quotation includes unit pricing by volume break, packaging specification and the earliest available production slot, so total landed cost can be compared rather than unit price alone.
The 1K0 prefix is commonly associated with Volkswagen Golf and Jetta model lines of the corresponding compact-platform generation, together with related models on the same chassis family. Because components were revised during production, fitment should be verified against the complete OE number on the original part or through a parts-catalogue lookup before ordering.
The unsuffixed number is the base design reference and the P suffix marks a later production revision of the same part family. Parts catalogues commonly cross-list both forms. Quote the complete number found on the original component, including the suffix, and add the measured dimensions so the factory can confirm the correct reference.
Measure the inner diameter, outer diameter and free height. For this reference the approximate values are 14.5 mm, 79.8 mm and 134.6 mm. Significant deviations usually indicate a different variant, so the OE number should be re-checked before an order is placed.
Yes. OEM and custom design support covers product dimensions, material and hardness, and also colour and branding options on the packaging. Standard shipments remain neutral and unbranded unless custom packaging has been agreed in advance.
