Volkswagen Strut Bump Stop 1K0511353J: OEM and Custom Polyurethane Replacement Parts for SKODA, SEAT and Audi from China Factory

Volkswagen Group produced several million vehicles on its compact A5 platform between 2003 and the middle of the 2010s, and a large share of them still runs on original rear dampers that are now due for a second or third overhaul. The elastomer buffer inside the rear shock absorber is one of the components that ages fastest on this axle. Bonpora supplies a replacement under Bonpora No. 4110247, matching OE number 1K0511353J, molded in micro-cellular polyurethane with a free height of 101 mm. This page is written for importers, auto parts distributors, and suspension workshops that source VW Group components by OEM number and need a dependable factory channel for rear axle buffers.

In the Volkswagen parts book, 1K0511353J appears as the jounce bumper of the rear shock absorber and is listed together with the dust cover set under related numbers 1K0513425 and 1K0513425B. The buffer slides onto the piston rod of the rear damper and cushions the final stage of compression travel before metal can strike metal. When the buffer cracks, tears, or collapses, the rear axle bottoms out on potholes and speed bumps, ride comfort drops under load, and dust and water reach the damper rod, which shortens the service life of the shock absorber seal. Workshops therefore replace the bump stop together with the damper or the dust cover during rear axle service. Related suspension components can be found in our shock absorber parts catalog.

What Is the 1K0511353J Strut Bump Stop?

Function in the Rear Axle

A strut bump stop, also called a jounce bumper or suspension buffer, is a compression element that engages only during the last part of suspension travel. Under normal driving the coil spring carries the load and the buffer does not work. When the wheel drops into a deep pothole or the vehicle carries heavy cargo, the spring reaches its limit and the damper rod would strike the top mount without protection. The polyurethane buffer compresses progressively, absorbs the impact energy, and returns to shape after the load is released. This protects the damper, the body structure, and the passengers from harsh metallic impacts.

Boot Kit Design and Related OE Numbers

For the rear axle of the A5 platform, Volkswagen combines the bump stop with the dust cover in one service kit. The buffer 1K0511353J has a free height of about 101 to 102 mm according to independent parts catalogs, and it works together with dust covers 1K0513425 and 1K0513425B. Buyers should note that the 1K0511353 family includes several suffixes, such as 1K0511353M and 1K0511353N, which are taller buffers of about 133 mm used on later Jetta models. The suffix therefore matters: always confirm the full OE number or measure the height of the old buffer before ordering.

Technical Specifications of Bonpora No. 4110247

The table below lists the parameters of the Bonpora replacement. Buyers who order by size can use the free height of 101 mm as the reference value, and buyers who order by OE number can match 1K0511353J directly.

Vehicle Applications: SKODA, VW, SEAT and AUDI Models

OE 1K0511353J covers the compact vehicle families of the VW Group built on the shared A5 platform from 2003 onward. The list below shows the main applications known from European and international catalogs. Because the same platform was delivered with different rear buffer heights depending on market, model year, and equipment level, buyers should confirm the fitment against the VIN or the full OE number before placing a bulk order.

Some independent catalogs also reference the related buffer 1K0511353N for the Audi TT (8J) and later Jetta models, so a side by side height check of the old part remains the safest verification method.

OEM Number Cross-Reference for 1K0511353J

Purchasers usually start from one of three entry points: the full VW OE number 1K0511353J, the related dust cover numbers 1K0513425 and 1K0513425B, or the internal numbers of aftermarket brands that list the same application. Independent suppliers such as Febest, Meyle, and Sidem market this rear axle application under their own numbering systems, so one physical part can carry a dozen commercial references. The reliable method is to compare three data points: the axle position (rear), the free height, and the shape of the mounting bore. Bonpora ships buffers that match the OE geometry, and our engineering team can check an unknown sample against the OE drawing on request.

Why Polyurethane Instead of Rubber

Original bump stops of this generation are produced from micro-cellular polyurethane foam, and Bonpora keeps the same material class for the replacement. Compared with conventional rubber, polyurethane offers a more stable compression curve over temperature changes, better resistance to ozone and road salt, and a lower permanent set after repeated impacts. The foam structure allows a soft initial response and a progressive rise in stiffness, which keeps the cushioning action predictable over the service life of the part. For distributors, the practical benefit is a lower return rate on suspension buffers, because polyurethane parts resist the cracking and powdering that usually end the life of a rubber buffer. The full range of molded buffers can be reviewed in the polyurethane bump stops section.

OEM and Custom Strut Bump Stop Manufacturing

Production Based on Drawings or Samples

Bonpora is a manufacturer of polyurethane suspension buffers. Besides the standard program that covers OE numbers for European, Asian, and American vehicles, the factory supports OEM production for brand owners and wholesale distributors. Customers can send a technical drawing, a physical sample, or simply the required height, outer diameter, and bore. The engineering team then selects the foam density and the compression characteristic so that the new buffer behaves like the original part. Existing molds cover several hundred references, and tooling for a new custom buffer is quoted separately after drawing review.

Branding, Packaging, and Private Label

The standard condition is neutral export packaging with the Bonpora article number on the label. For distributors with their own brand, the factory prints customer labels and carton marks from an agreed artwork, and it can pack the buffers as single parts or as complete rear axle boot kits together with dust covers on request. This private label service is used by importers in Europe, South America, the Middle East, and Southeast Asia who sell suspension buffers under local brand names.

Quality Control, Packaging and Delivery

Each production batch passes dimensional checks on height and bore, hardness verification, and a visual inspection of the foam surface before packing. The parts are packed in polybags and export cartons, and palletized shipments are prepared for full container orders. The standard lead time is 15 to 30 days depending on order quantity and mold availability. Samples for fitment verification are available before bulk production, and shipping documents are issued to match the commercial invoice for customs clearance.

FAQ About the 1K0511353J Strut Bump Stop

What is the difference between 1K0511353J and 1K0511353M or N?

They belong to the same rear axle buffer family but have different free heights. The J suffix corresponds to a buffer of about 101 to 102 mm, while the M and N versions measure about 133 mm and are fitted to later Jetta models. Confirm the full OE number or measure the old buffer before ordering.

Is the dust cover included with this bump stop?

In the VW parts book, 1K0511353J is listed together with dust covers 1K0513425 and 1K0513425B as a rear damper service kit. Bonpora supplies the polyurethane buffer as the main article, and the matching dust cover set can be quoted and packed together on request.

Which vehicles does OE 1K0511353J fit?

It fits the compact models of the VW Group on the A5 platform, including VW Golf V and VI, Golf Plus, Touran, Jetta, Audi A3 8P, SEAT Altea, and SKODA Octavia II. Because buffer heights differ inside the same platform, always verify the OE number or the height of the old part against the specifications on this page.

Can you produce a custom height or hardness?

Yes. Bonpora supports OEM and custom design service. Send the drawing, the OE number, or a sample together with the required height and hardness, and the factory will quote tooling and unit price accordingly. The delivery time for standard references is 15 to 30 days.

Whether you need a single batch of 1K0511353J buffers for a workshop network or a private label program of rear axle boot kits, the Bonpora sales team can prepare an offer with confirmed specifications and a clear lead time. Contact us through the contact information page with your target OE number, quantity, and destination port, and you will receive a quotation with packing details.