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The rear strut bump stop 13367145 is the compression buffer fitted to the rear axle of the Opel Astra K, the B16 generation sold from 2015. Bonpora supplies the same component in micro-cellular polyurethane as number 4110141, direct from the factory in China for wholesale buyers. This guide explains what the part does, which cars it fits, how it differs from the front buffer of the same car, and what to check before ordering.
The Astra K rear axle is a torsion beam with separate coil springs, and at full compression the spring collapses onto a long polyurethane buffer instead of onto bare metal.
Under normal load the buffer does nothing: the coil spring carries the body and the damper controls the wheel. When the rear of the car is heavily laden and a wheel meets a sharp ridge, the spring runs out of travel and the axle heads for its upper limit. The 13367145 compresses progressively at that point, turning the last part of the stroke into a controlled deceleration rather than a hard knock that passengers would feel through the floor. It also protects the damper, which wears its seals faster when repeatedly driven to full compression.
The part is a tall block of micro-cellular polyurethane about 145 mm long, with an outside diameter of about 58 mm and a 12 mm bore. Catalogue drawings place it above the rear spring, locating over a pin on the axle beam inside the spring seat assembly. Length is therefore the critical dimension, and the bore and head diameter decide how the buffer seats against the pin and the spring.
A worn rear buffer rarely announces itself on smooth roads. The usual symptoms are a hollow thud from the back over sharp compressions, a harsher ride when the boot is loaded, and a cracked, crumbling or crushed block found during rear suspension work. Because the buffer is inexpensive next to the spring and the beam, workshops normally renew it whenever the rear springs come apart.
European catalogues list the reference across the whole Astra K family, as summarised below.
| Model | Body | Catalogue years | Engines listed | Position |
|---|---|---|---|---|
| Opel Astra K | Hatchback (B16) | 2015-2022, records to 2024 | 1.0, 1.2, 1.4, 1.4 CNG, 1.4 Turbo, 1.5 D, 1.6 D, 1.6 BiTurbo, 1.6 Turbo | Rear, 1 per side |
| Opel Astra K | Sports Tourer estate (B16) | 2015-2022, records to 2024 | Same engine range | Rear, 1 per side |
| Opel Astra K | Estate and hatchback van versions | 2018 onwards | 1.0, 1.4, 1.5 D, 1.6 D | Rear, 1 per side |
Catalogue data covers the full engine range, from the three-cylinder 1.0 Turbo to the 200 hp 1.6 Turbo, including the 1.4 CNG, the 1.5 CRDI diesel introduced in 2019 and the 1.6 BiTurbo. Outputs run from 90 to 200 hp, and the buffer is the same across the range because the rear beam and spring package is shared, including the 1.2 Turbo engines of the 2019 update.
Most European catalogues close the application at the end of 2022, while some listings extend the record to 2024 or beyond, reflecting continuing production and registered vehicles still in service. The moulded number on the removed part remains the deciding check.
The Sports Tourer estate shares the rear axle with the hatchback, and the light-van versions of the Astra K appear in the same catalogue rows from 2018. Buyers serving fleet customers can quote one reference across body styles, which simplifies stock planning.
The Astra K carries two different bump stop references, one per axle, and confusing them is the most common ordering error on this platform.
The buffer at the front struts of the same Astra K carries reference 13424963. It is a much shorter part, about 68 mm long and 54 mm across, and catalogues list it for the Astra K together with the Chevrolet Cruze J300 and J400 bodies, which share the platform. Febi 109589, SWAG 33 10 0249 and Meyle 626 623 0036 are among its aftermarket equivalents.
The two buffers are not interchangeable: a 145 mm body cannot pass for a 68 mm one. Enquiries sometimes quote only the model name, so the export desk confirms the axle position and the length before quoting. Front and rear references on GM-platform vehicles rarely share a number, so quotations must state the axle.
The drawing data below summarises the part as supplied from the factory.
| Item | Value |
|---|---|
| Bonpora number | 4110141 |
| OE reference | 13367145 (013367145) |
| Position | Rear axle, both sides, 1 per side |
| Nominal size, Bonpora data | Bore 12 x OD 58 x length 145 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 12 mm, outside diameter 58 mm, length 145 mm. Aftermarket data agrees: the Febi 109453 equivalent measures 146 mm long and 60 mm wide with a listed weight of 0.132 kg, and the VEMA 380610 equivalent records 147 mm and 60 mm. The small spread reflects how the tapered body is measured and does not change the application. Match the removed part against the 145 mm length before ordering.
Enquiries for this part often arrive quoting an aftermarket number instead of the OE. The main equivalents are Febi Bilstein 109453, SWAG 42 10 9453, Sachs 900 469, Sasic 2650232, Original Imperium 360136, BIRTH 56767, BOGE 89-469-0, Maxgear 72-7286 and VEMA 380610. All describe the same rear buffer, so one stock line answers the whole family of references.
Bonpora moulds this buffer in micro-cellular polyurethane rather than filled rubber. The material choice matters to wholesalers because it 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 rear buffer sits under the load space, where a loaded boot, heat from the exhaust route 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 beam axle across the service life of the vehicle. 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: length, outside diameter and bore must match the removed part.
The demand behind this article is simple: 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 number and the drawing before dispatch. Buyers who require strict conformity can request samples first and measure them against the 145 x 58 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 length and the outside diameter and the factory will match the drawing. Buyers building a wider GM-platform programme can browse the chassis and suspension catalogue alongside this line, where buffers, mounts and related hardware are grouped for one-stop purchasing.
Yes. Catalogues record the reference with and without the leading zero, and both point at the same rear buffer for the Astra K. Febi 109453, SWAG 42 10 9453 and Sachs 900 469 are the common aftermarket equivalents.
No. The front struts of the Astra K use a different, much shorter buffer under number 13424963, shared with the Chevrolet Cruze. Confirm the axle and compare lengths: about 145 mm for the rear part against about 68 mm for the front.
One per rear side, two per vehicle, and the part is not handed. Catalogues note the required quantity as two for the rear axle, and workshops normally renew the pair together.
Yes. The polyurethane line covers a wide range of Opel and Vauxhall references across several generations, and custom moulding is available for sizes outside the standard range. Send the OE number or the dimensions and the export desk will confirm availability and terms.
Bonpora manufactures and exports suspension buffers from China for wholesale buyers worldwide. Quote 13367145 or 4110141 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.
