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The strut bump stop is a small component with an outsized influence on ride comfort and suspension durability. OE number 5Q0412303 is one of the frequently requested references in the Volkswagen Group aftermarket, appearing on inquiries from distributors who serve Audi, Seat, Skoda and Volkswagen vehicles. Bonpora supplies this part under No. 4110003 as a polyurethane strut bump stop, size Φ19.3 x Φ59.5 x 85 mm, with OEM and custom design support for buyers who need original-referenced or tailored replacement parts. This guide summarizes the product, its fitment logic across the shared platform family, and the sourcing routes trade buyers most often use.
A strut bump stop — also known as a jounce bumper or suspension bump stop — sits on the damper rod of a MacPherson strut assembly, usually inside or alongside the dust cover. During normal driving it stays out of contact. When the suspension compresses beyond its designed travel — a deep pothole, a fully loaded vehicle, a speed bump taken quickly — the bump stop engages and cushions the final part of the stroke.
Without a functioning bump stop, the strut reaches metal-to-metal contact. The results are familiar to any workshop: a hard clunk over bumps, accelerated seal and rod wear on the damper, and reduced occupant comfort. Replacing a worn bump stop during strut service is inexpensive insurance for the damper itself, which is why many distributors stock bump stops alongside shock absorber parts.
The table below lists the main parameters of Bonpora No. 4110003, the replacement part matched to OE 5Q0412303.
| Parameter | Value |
|---|---|
| Product Name | Strut Bump Stop |
| OE Reference | 5Q0412303 |
| Bonpora No. | 4110003 |
| Fitment | Audi / Seat / Skoda / Volkswagen |
| Size | Φ19.3 x Φ59.5 x 85 mm |
| Material | Polyurethane |
| Country of Origin | China |
| Warranty | 1 Year |
| Delivery Time | 15-30 Days |
| Packaging | Neutral Export Packaging |
| Custom Service | OEM & Custom Design Support |
The three dimensions matter most when cross-referencing: the rod hole diameter (19.3 mm), the outer diameter (59.5 mm), and the free height (85 mm). A correct match keeps the stop aligned on the strut shaft and engages at the intended travel point. The 85 mm free height is longer than many compact-car stops, so measuring the part in hand before ordering is strongly recommended.
The 5Q0 prefix of OE 5Q0412303 is associated with the Volkswagen Group shared platform family, which underpins compact and mid-size models sold under the Audi, Seat, Skoda and Volkswagen brands. Because these platforms share strut assemblies across model years and trims, a single bump stop reference can serve several model lines at once — convenient for stock planning, but also a reason fitment should always be verified rather than assumed. Trade buyers typically confirm by one of three methods:
Different buyer profiles approach this product from different angles, and the search terms they use reflect it.
Wholesalers and catalog-driven distributors usually search by the OE reference itself — 5Q0412303 bump stop or 5Q0412303 supplier. This route gives the tightest match because the part number ties directly to tooling and dimensional records. When you send an OE number, include the target quantity and any packaging requirements; the supplier can then confirm mold availability and quote in one round.
Repair chains and regional distributors more often search vehicle-first: Audi bump stop, Skoda strut bump stop, bump stop for Octavia, or VW Golf bump stop. This works well, but model-based searching can surface several similar stops within one platform family. Confirming the OE number or dimensions before ordering avoids shipping a part that looks right but engages at the wrong travel point.
Suspension assemblers and engineering distributors sometimes work the other way around: they have dimensions and material requirements but no OE reference. In that case, quote the three key dimensions and the material (polyurethane, hardness if known). The factory can match an existing mold or, if none fits, open a custom one. The jounce bumper and bump stop catalog from Bonpora covers the standard range, and unmolded sizes move through the custom program.
Brands and large distributors frequently combine the two approaches: a standard reference part with private-label packaging, or a modified design with adjusted hardness or geometry. Bonpora supports OEM & custom design service — from drawings or physical samples — including material tuning and branded export packaging. Details of the custom workflow are on the custom parts page.
Bump stops work in a harsh zone of the suspension: repeated high-strain compression, contamination from water and road salt, and wide temperature swings. Conventional rubber stops harden and crumble with age, which is why a cracked bump stop is a common workshop finding on older vehicles.
Polyurethane microcellular foam behaves differently. Its closed-cell structure compresses progressively and recovers without permanent set, and it resists aging, ozone, and temperature extremes better than standard rubber. For the buyer this translates into two practical points: longer shelf life in the warehouse, and more consistent damping behavior across the service life of the part. The same material family is used across the shock absorber parts range from Bonpora, which simplifies sourcing when a distributor consolidates suspension wear parts with one factory.
Bonpora manufactures under an IATF 16949 quality system. For bump stop production this covers, in practice: incoming material verification for the PU systems, in-process control of foaming parameters, and dimensional inspection of finished parts against the mold specification. Batch samples are checked for hardness and compression behavior so that replacement batches behave consistently with earlier deliveries.
The part is supplied with a 1-year warranty. As with any suspension component, the warranty covers manufacturing defects; correct application of the part to the intended fitment remains the responsibility of the buyer, which is another reason the OE-number verification step above matters.
Standard supply uses neutral export packaging — suitable for distributors who re-box under their own brand. Each stop is bagged and cartoned to prevent compression damage in transit; custom packaging and logo printing are available in the OEM program. Production and delivery take 15-30 days depending on order size and season, and mixed loading with other suspension references is possible for container programs.
The reference belongs to the Volkswagen Group shared platform family and is cataloged for Audi, Seat, Skoda and Volkswagen applications. Because the same strut family can be shared across models and model years, we recommend confirming fitment by OE number, dimensions (Φ19.3 x Φ59.5 x 85 mm), or VIN before ordering. Send the reference and our team will check it against mold records.
Yes. Existing molds cover the standard range; if your requirement differs in size, hardness, or geometry, the custom program can develop the part from a drawing or a physical sample. Mold opening and sampling timelines are confirmed case by case.
Standard catalog parts are available in distributor-friendly quantities, and production plus delivery typically run 15-30 days. Exact MOQ depends on the reference and packaging choice — neutral export packaging ships fastest, while private-label packaging adds production time.
Check the three key dimensions first: rod hole diameter, outer diameter, and free height. Then compare the foam texture and mounting method (through-rod versus cup type). If you send a sample or dimensional drawing, the factory will confirm the match before quotation.
For pricing on Bonpora No. 4110003 (OE 5Q0412303), send the OE number, target quantity, and destination port to our sales team. OEM and custom design inquiries are welcome — include a drawing or sample description and we will respond with mold feasibility, unit pricing, and delivery terms for your market.
