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A strut bump stop is a low-cost component with a disproportionate effect on how a suspension job feels to the customer. When it is missing, worn, or mismatched, the strut bottoms out with a metallic knock and the workshop sees the car again within weeks. This page describes the Volkswagen strut bump stop referenced under OE number 2K0511155A and Bonpora number 4110056, supplied factory-direct from China. It covers what the part does, how to verify fitment, how original and replacement supply compare, and what importers and distributors should confirm before committing to a volume order.
Also sold under the names jounce bumper, bump stopper, and suspension buffer, the part is a moulded elastomer sleeve that fits over the damper piston rod inside the strut. During normal driving it hangs clear of the top mount. Under a hard compression event — a pothole, a speed bump, a fully loaded vehicle — it engages progressively and converts what would otherwise be a metal-to-metal impact into controlled resistance.
Elastomer parts age whether the car is driven or parked. Heat, ozone, road salt, and repeated compression cycles harden the material until it cracks and loses its progressive response. From that point the damper begins to bottom out and the damage spreads to the mount and the shock absorber. For the wider suspension range, see our auto parts catalogue.
The item described here is a strut bump stop for Volkswagen applications, produced in a dedicated auto parts factory in China and referenced under OE number 2K0511155A and Bonpora number 4110056. The table below lists the data buyers normally request before asking for a quotation.
| Parameter | Value |
|---|---|
| Product name | Strut Bump Stop |
| OE number | 2K0511155A |
| Bonpora no. | 4110056 |
| Fitment | Volkswagen |
| Dimensions | Φ16 x Φ49.1 x 54.7 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 |
Φ16 mm is the inner bore that slides over the damper rod, Φ49.1 mm is the outer diameter of the elastomer body, and 54.7 mm is the free length. The bore determines whether the part can be assembled at all; the free length determines where in the stroke it starts to work. The compact 54.7 mm free length points to a strut with a short progressive stage, which is why substituting a stop from a different application so often causes complaints — a longer stop engages early and makes the ride firm, while a shorter one engages too late and lets the strut knock. Compare all three values against the part removed from the vehicle before approving any substitution.
Polyurethane suits this duty cycle well. Compared with conventional rubber it resists tearing and oil exposure better, holds its mechanical properties across a wider temperature range, and can be moulded to a controlled hardness so the compression curve stays progressive rather than abrupt. For Volkswagens in commercial use that carry regular loads — delivery duty, tradesman conversions, family transport with a full cabin — that consistency is what keeps replacement intervals predictable.
In Volkswagen part numbering, the 2K prefix is commonly associated with the Caddy family, and components introduced on that line often carry the prefix even when they are cross-fitted across related models in the range. Catalogues list OE 2K0511155A within the Volkswagen passenger and light commercial spectrum, but regional model naming and mid-cycle running changes mean the application list should always be treated as guidance rather than a guarantee. The OE number moulded on the removed part, or the vehicle identification number, remains the most reliable basis for ordering.
Demand behind this reference usually comes from two buyer groups: those who need an original-equivalent part for a vehicle under care, and those building a replacement programme for the independent aftermarket. Both are served from the same tooling and quality system, which is what makes factory-direct supply attractive in this category.
An original-quality replacement reproduces the reference part where it counts: the same bore and free length, an equivalent material grade and hardness, and a compression curve close to the OE component. It does not require the OE brand name, and it should not be presented as such — it is a replacement part manufactured to the original specification. For workshops this is the practical middle ground between dealer supply and unverified market alternatives.
Buying from the producing factory removes one or more trading layers, which shows up in quotation stability and in the ability to answer technical questions quickly: Shore hardness values, cure process, and dimensional inspection reports. It also makes private-label packaging and carton marking straightforward, which matters to distributors building their own suspension range. If you are comparing suppliers, our auto parts sourcing team can review drawings, samples, and cross-reference lists alongside catalogue items.
Bump stops are a low-unit-value, high-turnover line that supports higher-margin suspension sales. Sourcing them well is mostly about batch consistency and documentation rather than the lowest quotation.
A factory with OEM and custom design capability can produce stops to a customer drawing or sample, including non-standard bore sizes, alternative hardness grades, and application-specific profiles. This suits distributors building a private-label range as well as specialists servicing vehicles with modified ride heights. Send the drawing together with the target annual volume so the quotation reflects tooling, material, and order size realistically.
For catalogue items held in stock, 15–30 days covers production and export preparation. New tooling adds development time, so plan the first order of a private-label line well ahead of the selling season, and confirm the shipping method and destination port when requesting the quotation.
A worn bump stop is often discovered during damper replacement, but it can also be diagnosed from the driver seat before the car goes on the lift.
Bump stops are normally replaced together with the strut mount and dust boot, since all three share the same access procedure and a similar service life. Replace both sides of the axle at the same time, support the suspension correctly before releasing fasteners, and torque the components with the vehicle at normal ride height. Compare the old elastomer part against the new item before installation to confirm that bore, diameter, and free length match the application.
The reference is catalogued for Volkswagen applications, and the 2K prefix is commonly associated with the Caddy family. Because running changes and regional naming vary, confirm the application with the vehicle identification number or the OE number on the removed part before ordering, and ask the factory for a written cross-reference list covering the models you service.
A replacement manufactured to the original specification — matching bore, free length, material grade, and hardness — performs the same function as the OE part. Ask the factory for dimensional inspection data and material details so the comparison is documented rather than assumed.
Yes. Where an existing mould matches your drawing, the catalogue reference is enough. Where profile, hardness, or length differ, the part can be moulded to your sample or drawing under an OEM programme, subject to a tooling discussion and a minimum order quantity agreed with the factory.
Quoted delivery is 15–30 days for stock-referenced items, with neutral export packaging prepared for sea or air freight. Confirm the shipping method and destination port when requesting the quotation so the terms match your planning.
If you are sourcing strut bump stops for Volkswagen applications, or planning an original and replacement programme under your own brand, send the OE number, target models, and annual volume. The factory can confirm availability, provide dimensional and material data, and quote on neutral export packaging or private-label terms.
