Opel Front Strut Bump Stop OE 90112571 03 44 401 for Kadett E and Astra F

The front suspension of an Opel Kadett E or Astra F still sees daily service in many markets, and the small rubber or polyurethane buffer that sits on the damper rod is one of the first parts to fail. Once it has crumbled, the strut no longer has anything to stop it from bottoming out, and the shock absorber, top mount and spring seat start to take the impact instead. This page covers the front axle strut bump stop supplied against OE 90112571 and Opel catalogue number 03 44 401, produced in our own tooling in polyurethane.

Our reference for this part is Bonpora No 4110076. The drawings call out a stepped body of Φ20.2 mm bore, Φ67.5 mm outside diameter and 69 mm overall height, moulded in polyurethane rather than the original EPDM rubber. The sections below explain how the part is identified, which Kadett and Astra variants it belongs to, and what a buyer should confirm before placing a container order.

What this front strut bump stop does

A MacPherson strut has a limited amount of travel. The bump stop is a progressive spring that absorbs the last part of that travel so the damper never reaches metal-to-metal contact. On the Kadett E and Astra F front leg the buffer slides on the damper rod above the dust cover and compresses against the upper spring seat.

Two failure modes matter commercially. Age hardening makes the rubber crack and break up, leaving fragments inside the dust boot. Overload compresses the buffer permanently, so it loses height and no longer protects the strut. Both are common on vehicles that carry loads or run on rough road surfaces.

Our engineers keep this part in polyurethane bump stops on the same fixing envelope as the rubber original. The material behaves differently in use, which is covered in the comparison table later on this page.

Identification: GM number and Opel catalogue number

This buffer carries two numbers, because Opel parts are listed both by the GM service number and by the Opel internal catalogue code.

• 90112571 is the GM / Vauxhall service number, printed on the dealer microfiche and used in TecDoc-based catalogues.
• 03 44 401 (also written 0344 401, 3 44 401 or 344401) is the Opel catalogue group number for a front axle suspension rubber buffer.

Both numbers refer to the same physical part. In the Opel numbering scheme, the group 3 44 covers front axle spring and buffer components, while the group 3 28 is used for rear axle parts of the same function. Reading the group correctly is the fastest way to avoid ordering a rear buffer for a front leg.

Specification

Vehicle applications

The application list for 90112571 / 03 44 401 is centred on the T85 and T92 compact platforms, which Opel built under several model names between the mid-1980s and the late 1990s.

The buffer fits petrol and diesel versions across the range. Engine codes covered by aftermarket catalogues include the 1.3, 1.4, 1.6, 1.7 D and TD, 1.8, and the 2.0 including the GSi and 16-valve units. Because the front leg geometry is shared, one buffer number covers the whole engine spread.

Buyer note: 03 44 401 and 03 44 402 are not the same height

Two adjacent catalogue numbers sit next to each other in Opel’s group and appear side by side in every cross-reference list, but they are different parts. Aftermarket manufacturers publish a nominal height of 70 mm for 03 44 401 and about 46 mm for 03 44 402, which points to two different spring and damper packages.

Some catalogue entries for 03 44 401 also carry the restriction for vehicles without sports suspension and recommend replacement in pairs. That wording is the important one. If the vehicle left the factory with a sports or lowered chassis, the front leg is shorter and the buffer that belongs to it may be the other number. The safe route is always to read the number off the old part, or to compare the old and new buffers side by side before fitting.

The dimensional difference is small in absolute terms but it directly changes how much travel remains before the strut bottoms out, so it should not be treated as a cosmetic variation.

Substitution and cross-reference numbers

The numbers below are published by independent aftermarket manufacturers as equivalents for the same front axle buffer. They are useful as search terms when a buyer works from a brand number rather than an Opel number, but they are not evidence of any commercial relationship with those brands.

Two observations are worth passing to a purchasing team. First, several of these entries are supplied as a dust cover kit containing two buffers rather than a single piece, so a low unit price is not necessarily comparable with a single-piece quotation. Second, catalogue heights vary between 68 mm and 70 mm for the same OE number, which reflects different measuring points on the stepped body rather than different parts. Our drawing value of 69 mm sits inside that band.

Polyurethane compared with the original rubber

The original buffer was moulded in EPDM rubber. Polyurethane is an alternative that several aftermarket manufacturers already use for this exact OE number, including entries marked PU in the catalogue data.

Because polyurethane is firmer, a vehicle converted to PU buffers will feel slightly more controlled over large bumps but a little stiffer over small ones. For fleet and export repair markets this trade is usually acceptable; for a collector car kept close to original specification, the choice is a matter of preference.

How to tell whether the buffer needs replacing

The symptom that sends most Kadett E and Astra F owners to a parts counter is a thud from the front end when the car crosses a speed hump, especially when loaded. On a lift, the diagnosis takes a few minutes.

• Look at the buffer. A cracked, swollen or crumbled buffer, or one that has shrunk away from the damper rod, has to be replaced.
• Look inside the dust cover. Rubber fragments collected there show the buffer has broken up, and the cover should be cleaned or renewed at the same time.
• Compare both sides. If one buffer is noticeably shorter than the other, both are due, because they wear together.
• Check the damper rod. Scoring or an oil film means the shock absorber has passed the end of its life, and a new buffer alone will not cure the noise.
• Check the top mount and spring seat. A worn top mount gives a similar clunk and is reached during the same job.

Ordering points for wholesale buyers

Confirm the position and quantity

This is a front axle buffer and every vehicle needs two. A kit that contains two buffers is priced per vehicle, not per unit, so quotations should always state the unit quantity included.

Check chassis variants before fixing the order

Confirm whether the vehicles in the order are standard or sports chassis. Mixing the two numbers in one shipment is possible, but they should be packed and labelled separately so the warehouse does not mix them at the counter.

Related parts worth listing together

When a buffer has failed, the surrounding parts are usually at the end of their life as well. Buyers commonly add the front dust cover, the strut top mount and the upper spring seat to the same order, since the labour to reach the buffer is the same in all cases. Our chassis and suspension parts range covers these items, and we can quote a repair kit for a full front leg rebuild.

Packaging, branding and lead time

Standard supply is neutral export packaging with a plain carton and a printed label carrying the OE number, our reference and the quantity. Custom printing, private label cartons and OEM numbering are available. Production and shipping normally take 15 to 30 days depending on order volume and moulding schedule.

Why this part still sells in volume

The Kadett E was built well into the 1990s and the Astra F carried on in Classic form for several years after that. In Europe the surviving cars are now more than thirty years old, and in Africa, the Middle East, Latin America and parts of Eastern Europe the same platforms are still in daily commercial use as taxis, delivery vans and family cars.

That keeps demand steady rather than seasonal. Repair shops in these markets order in small quantities at short notice, while importers consolidate the same number with other Opel suspension items into mixed containers. Because the buffer is small and light, it is an easy line to add to a shipment already being built around larger suspension components.

The practical consequence is that quality consistency matters more than a marginal price difference. A buffer that hardens early, or that has been moulded a few millimetres short, will come back as a warranty claim long before the shipment has cleared the local distributor network.

Frequently asked questions

Is 90112571 the same part as 03 44 401?

Yes. 90112571 is the GM and Vauxhall service number and 03 44 401 is the Opel catalogue number for the same front axle suspension buffer. Either number can be used to place an order, and both appear on our label.

Will this buffer fit a Kadett E and an Astra F?

Both models use the same front leg family, so one buffer number covers the Kadett E (T85) and the Astra F (T92), including the Classic and the Vauxhall-badged versions. Vehicles with a sports or lowered chassis need to be checked separately, because the adjacent 03 44 402 belongs to a different setup.

Can you supply it in polyurethane instead of rubber?

Yes, the part shown here is moulded in polyurethane to the same drawing envelope of Φ20.2 x Φ67.5 x 69 mm. We can also produce it in rubber if a customer specifically requires the original material for a stock-correct restoration order.

What is the minimum order and the lead time?

We quote both sample quantities and container loads. Standard production and delivery run 15 to 30 days after drawing confirmation, and custom moulding or private label work is quoted with its own schedule.

Request a quotation

Send us the OE number, the expected annual volume and any chassis variant details, and we will confirm price, packing configuration and delivery schedule. Drawings and dimensional reports for Bonpora No 4110076 are available on request so your technical team can verify the bore, outside diameter and height against an original part. Custom and OEM design support is available for buyers who need a different compound, a revised height or their own packaging.