Strut Bump Stop 1KD511359: 134mm Rear Suspension Buffer for VW Magotan, Sagitar, Passat and Tiguan

1KD511359 is a rear axle strut bump stop (also written 1KD 511 359) used across Volkswagen Group multi-link rear suspension. Its 134 mm free length and 63 mm outer diameter place it in the same height class as the widely catalogued 3C0511359 buffer, so it is the number buyers reach for when a Magotan, Sagitar, Passat or Tiguan rear shock needs new progressive cushioning. This guide covers the measurements, the fitment windows, the interchange numbers and the ordering checks that matter when you are sourcing these buffers in volume from a Chinese factory.

What 1KD511359 Actually Is

The part is a polyurethane jounce bumper that sits on the rear shock absorber rod, inside the coil spring. Under compression it takes over from the spring at the end of the travel, absorbing the last part of the stroke instead of letting metal contact metal. On the PQ35 and PQ46 families the rear axle runs a multi-link layout, and the buffer is what keeps the damper from bottoming out when the car is loaded or the road is rough.

Two material details drive the service life. Polyurethane (PU) resists oil, road salt and ozone far better than the plain rubber used on many original buffers, and it holds its shape after repeated compression cycles. Febi lists this buffer family as PU with a round profile, and the same class of part is what the aftermarket treats as the premium replacement option.

Rear Axle Only: The 359 Suffix Trap

One field of confusion costs buyers real money. Volkswagen Group uses two different bumper families whose numbers both end in 359, and they are not interchangeable:

If a supplier quotes 1KD412303 against a rear axle enquiry, or bundles the two together as one kit without stating position, treat that as a specification error rather than a bargain. The 1KD412303 unit is a front strut buffer and will not seat correctly on the rear damper rod.

Measurements and Material

The 134 mm figure is the free standing length before installation. Compressed height is a separate number and should be requested from the supplier when you are matching a competitor part on a bench. Independent catalogues list the equivalent 3C0511359 buffer at 133 mm with a 16 mm inner bore and 96 g, and one manufacturer records 63 mm outer diameter with a 16 mm bore. The small differences reflect measurement convention and mould shrinkage, so always state which dimension your drawing controls.

Vehicle Applications

The rear multi-link axle that takes 1KD511359 ran through several markets under different model names. Coverage from 2006 to 2015 is the core window.

Two practical notes on this list. First, the Audi A1 application depends on suspension configuration. Febi records the equivalent buffer as suitable for vehicles without electronic suspension control, so an A1 with adaptive damping may take a different number. Second, on many of these cars the rear bumper and the dust cover are replaced together as a set, because the boot has to come off anyway and it hardens at the same rate. If the customer wants a complete rear refresh, quote the buffer alongside the dust covers so the kit arrives in one shipment.

Interchange Numbers and Cross References

Use this table when the customer sends a competitor number and asks for a match. All entries below are reference-only equivalents, and final confirmation should always be against the OE number.

A caution on this table. Several of these brands list more than one height under a single family name, and the 118 mm and 133 mm buffers are visually similar on a photograph. Ask for the length in millimetres in writing before you confirm a container load. If a buyer is matching against a suspension upgrade rather than a standard repair, the sports suspension listing may point to a different height, so state the vehicle configuration in the enquiry.

Sourcing 1KD511359 From a Chinese Factory

For importers and distributors, this buffer is a straightforward volume item. The mould is stable, the PU compound is mature, and the part ships in neutral export packaging by default, which means you can brand it for your own catalogue without paying for tooling changes.

What to Put in the Enquiry

• OE number: 1KD511359, and the alternates 3C0511359 and 1K0511359 if you want a height comparison.
• Free length, outer diameter and inner bore, with the tolerance your quality team accepts.
• Compound: polyurethane, and whether you need a specific hardness or colour coding.
• Vehicle list you intend to cover, so the supplier can flag any application that needs a different height.
• Packaging requirement: neutral carton, your own printed box, or bulk bag.
• Annual volume and shipment frequency, which drive the unit price and the production slot.

Quality Checks That Pay Off

Ask for a dimensional report on the first article, not just a general certificate. The three dimensions that matter are free length, bore diameter and the seat shoulder profile. A buffer that is 2 mm short will still fit the rod but will change when the rear axle starts to bottom out, and that difference shows up as a comeback complaint rather than a failed incoming inspection.

Second, request the PU hardness value and a compression set figure. A soft compound feels comfortable for the first few thousand kilometres and then takes a permanent set, which is exactly the failure mode the original rubber part had. A well specified PU buffer should recover its free length after the test cycle.

Third, confirm the surface finish on the bore. A rough bore grips the damper rod and can damage the rod surface, which turns a low cost buffer into an expensive warranty claim. If your channel supplies workshops that install these weekly, the installation feel is part of the product quality.

When you build out the rear axle range, the same supplier conversation usually covers the matched components. Many buyers group the buffer with the polyurethane bump stops range and the rest of the rear axle hardware so the catalogue page holds together for the workshop customer.

Ordering Notes for Distributors

Three points come up repeatedly on this part number.

Quantity per vehicle. The rear axle uses two buffers, one per side. They wear at the same rate, so the trade expects to buy them in pairs and most catalogues list the required quantity as two. Stocking in single units creates a mismatch where the workshop orders one and then needs a second shipment.

Front and rear must not be mixed. The common front buffer on the same cars is 1KD412303 or 1K0412303, which is far shorter. Some suppliers sell a combined kit that covers front and rear together; that is acceptable if the kit clearly labels both positions and both heights. It is not acceptable if the kit substitutes one for the other.

VIN splits inside one model name. The Chinese market listings for Sagitar and Passat carry VIN break points, for example records from 1K-B3000 001 and later from 1K-B4000 001 on Sagitar, and from 56-B-000 001 on Passat. Ask the buyer for the VIN when the order is for a body shop rather than a general service customer, because a change of supplier or spring specification across that break can move the part number.

Frequently Asked Questions

Is 1KD511359 the same as 3C0511359?

For practical purposes they are treated as equivalents on the rear axle. The 3C0511359 number is the main B6 and B7 generation reference and the 1KD511359 number is the multi-market version of the same buffer. Independent catalogues list 3C0511359 dimensions at 133 mm to 134 mm, which matches the 134.2 mm free length of 1KD511359. Always confirm the length with your supplier before a large order, since the two numbers occasionally appear with different stated heights across brands.

Does this part fit the front axle as well?

No. 1KD511359 is a rear axle buffer. The front position on these vehicles uses a different, much shorter bumper, commonly listed under 1KD412303 or 1K0412303. Fitting a rear buffer to a front strut will not seat correctly and will change the suspension travel. If a quotation offers one part to cover both ends of the car, ask for the position and the height in writing.

How many do I need per vehicle?

Two, one for each side of the rear axle. They should be replaced as a pair, because both have seen the same service life and the same road conditions. When replacing the buffer, inspect the dust cover and the top mount at the same time, since the labour to access the rear strut is the main cost of the job.

Can you supply custom packaging or a custom compound?

Yes. The standard offer ships in neutral export packaging, and OEM and custom design support is available for buyers who need their own brand, a specific carton layout or a tailored PU hardness. Typical delivery time is 15 to 30 days depending on volume and whether a first article approval is required, and the part carries a 1 year warranty.

Request a Quotation

Bonpora supplies 1KD511359 rear strut bump stops in polyurethane, with neutral export packaging, OEM and custom design support, a 1 year warranty and a typical 15 to 30 day delivery window. Send your required quantity, the vehicle list you intend to cover and your packaging requirement, and we will confirm the dimensional report and a quotation. For the wider rear axle range, review our chassis and suspension components as well, so a single order covers the whole repair.