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The front strut bump stop 2053211606 is the progressive compression buffer fitted inside the front struts of the Mercedes-Benz C-Class W205 family. Bonpora supplies the same component in micro-cellular polyurethane as number 4110138, direct from the factory in China for wholesale buyers. This guide explains what the part does, which vehicles the reference covers, how the catalogues name it, and what to check before ordering.
The W205 front axle uses coil spring struts, and each strut carries a polyurethane buffer on the damper rod, seated between the top mount and the spring seat.
Under normal load the buffer does nothing: the coil spring carries the body and the damper controls the wheel. When a sharp ridge or a pothole drives the spring to full travel, the strut heads for its upper limit. The 2053211606 compresses progressively at that point, turning the last part of the stroke into a controlled deceleration rather than a hard knock through the body. It also protects the damper, whose rod seals wear faster when the strut is repeatedly driven to full compression.
The part is a ring of micro-cellular polyurethane about 60.5 mm tall with an outside diameter of about 56.9 mm and an 11.8 mm bore, and aftermarket catalogues list it with a weight of around 50 g. The bore locates the buffer on the damper rod, while the flared head closes against the spring seat. The short height is typical of this platform class.
A worn front buffer rarely announces itself on smooth roads. The usual symptoms are a hollow knock from the front over sharp compressions, harsher reactions to potholes, and a crumbled, cracked or crushed buffer found during strut or top mount work. Because the buffer is inexpensive next to the strut assembly, workshops normally renew it whenever the front struts come apart.
Aftermarket catalogues apply the reference across the 205-platform body range, as summarised below.
| Model | Body code | Body style | Catalogue years | Position |
|---|---|---|---|---|
| Mercedes-Benz C-Class | W205 | Saloon | 2014-2021 | Front, both sides |
| Mercedes-Benz C-Class | S205 | Estate | 2014-2021 | Front, both sides |
| Mercedes-Benz C-Class | C205 | Coupe | 2016 onwards, records to 2024 | Front, both sides |
| Mercedes-Benz C-Class | A205 | Cabriolet | 2016 onwards, records to 2024 | Front, both sides |
Catalogue data covers both the M274-engined pre-facelift cars and the M264-engined facelift cars from 2018, including the mild-hybrid EQ Boost versions and the C 350 e plug-in hybrid, so one reference serves both build phases.
Some catalogue records extend the application beyond the C-Class to the GLC (X253) and the electric EQC, which share front-axle hardware. These extensions come from aftermarket listings rather than the vehicle brand, so buyers serving GLC customers should match the removed part against the dimensions below before quoting.
The buffer described here is a front-axle part. The rear axle of the W205 uses a different buffer with its own reference number, and the two are not interchangeable. Enquiries should always state the axle position, and the export desk confirms the reference against the removed part when only the model name is quoted.
The most practical feature of this reference for wholesalers is its breadth: catalogues list the same buffer from the entry diesel to the top AMG models.
Catalogue engine lists for the reference run from 116 hp to 510 hp, covering the C 160, C 180, C 200, C 220 d, C 250, C 300, C 300 d, C 400, the C 450 AMG and AMG C 43, and the V8 AMG C 63 and C 63 S, in rear-wheel-drive and 4MATIC form alike. Because the catalogues apply one reference across the range, a single stock line answers retail, fleet and performance customers alike.
The drawing data below summarises the part as supplied from the factory.
| Item | Value |
|---|---|
| Bonpora number | 4110138 |
| OE reference | 2053211606 (A2053211606) |
| Position | Front axle, both sides, 1 per side |
| Nominal size, Bonpora data | Bore 11.8 x OD 56.9 x length 60.5 mm |
| Material | Micro-cellular polyurethane |
| Country of origin | China |
| Warranty | 1 year |
| Delivery | 15-30 days |
| Packaging | Neutral export packaging |
| Custom service | OEM and custom design support |
The Bonpora record reads bore 11.8 mm, outside diameter 56.9 mm, length 60.5 mm. The Febi 103965 equivalent records a length of 60.34 mm and a width of 56.6 mm with a listed weight of 50 g, and retail listings of a rubber version of the same reference quote about 62 x 56 mm with an 18 mm top opening. The spread reflects different measurement points on a part with a flared head; the deciding check is the height and outside diameter of the removed buffer.
Enquiries for this part often arrive quoting an aftermarket number instead of the OE. The main equivalents are Febi Bilstein 103965, Topran 409 437, Vaico V30-2879 and Original Imperium 38898. All describe the same front buffer, so one stock line answers the whole family of references.
The same component appears under several names, which matters when a buyer searches one term and the catalogue indexes another.
Buyers usually search for a front strut bump stop or a jounce bumper. The function is the same in every case: a progressive end-of-travel cushion mounted on the strut. This article keeps the trade term in the title and the body so that both search routes lead to the same page.
European aftermarket catalogues file the reference as a rubber buffer for the suspension, even where the material is polyurethane. When building enquiry lists it helps to search both terms, because a catalogue hit under either name points at the same position in the exploded drawing. Colour, yellow or black, is not a fit-relevant specification.
Bonpora moulds this buffer in micro-cellular polyurethane rather than filled rubber, a choice that changes how the part behaves on the vehicle.
| Property | Polyurethane (Bonpora) | Conventional rubber |
|---|---|---|
| Compression set | Low, recovers shape after repeated hits | Higher, takes a set over time |
| Ozone and heat ageing | Strong resistance | Cracks sooner in hot climates |
| Oil and fluid contact | Good resistance | Swells and softens |
| Load consistency | Uniform batch to batch | Varies with compound |
| Unit cost | Moderate | Lower |
The front buffers sit in the engine bay, where heat, oil mist and road spray age ordinary rubber quickly. A compound with a low compression set keeps its free length stable, protecting the travel reserve of the strut over the vehicle life. The full polyurethane bump stop range applies the same approach across other platforms.
A correctly sized buffer only works at the end of the stroke, so a polyurethane replacement does not change normal ride comfort. What decides the fit is the geometry: height, outside diameter and bore must match the removed part.
Buyers want the original part or a faithful replacement, sourced directly from a manufacturer with OEM capability.
A replacement part matches the OE reference in fit, dimensions and function without carrying the vehicle brand. Bonpora moulds buffers against the published OE data, and every enquiry is checked against the reference and drawing before dispatch. Buyers can request samples and measure them against the 60.5 x 56.9 mm figures.
For distributors with their own brands, the factory offers OEM labelling, branded boxes and private moulding. Custom design covers changes of compound hardness, free length or outer profile: send the sample or the drawing, and the tooling, minimum order and lead time are confirmed before production. Details of the programme are on the custom parts page.
Standard supply ships in neutral export packaging on a 15-30 day schedule with a one-year warranty, and pricing is quoted against order volume so that distributors can plan their season.
Send the OE number, the model year, the quantity per vehicle and the destination port to the export desk. If the number has worn away, quote the height and the outside diameter and the factory will match the drawing. Buyers building a wider Mercedes programme can browse the shock absorber parts catalogue alongside this line, where buffers, mounts and related hardware are grouped for one-stop purchasing.
Yes. The A prefix is the standard Mercedes-Benz part number format, and catalogues record the reference with the prefix, without it or in the spaced form 205 321 16 06. All point at the same front buffer; Febi 103965, Topran 409 437 and Vaico V30-2879 are the common aftermarket equivalents.
No. This reference covers the front axle, one buffer per side, two per vehicle. The rear axle of the W205 uses a different buffer with its own reference, and the two are not interchangeable. Confirm the axle and compare the removed part before ordering.
Catalogue records list the reference across the output range up to the AMG C 63 S at 510 hp, in rear-wheel-drive and 4MATIC form, so AMG front axles are included. Match the removed buffer against the dimensions where a car has been modified.
One per front side, two per vehicle, and the part is not handed. Workshops normally renew the pair together whenever the front struts are dismantled, because mixing a new buffer with a worn one upsets the end-of-travel behaviour.
Bonpora manufactures and exports suspension buffers from China for wholesale buyers worldwide. Quote 2053211606 or 4110138 with your quantity and destination, and the export desk will return unit pricing, packing details and the next available shipment. For the material background behind the range, the polyurethane bump stops overview is a good starting point.
