BMW Strut Bump Stop 31336764086 | OEM Replacement Supplier & Custom Manufacturer

What Is the BMW Strut Bump Stop 31336764086?

BMW part number 31336764086, also written as 31 33 6 764 086, is the front strut bump stop for the 5 Series E60 saloon and E61 Touring. In the official BMW parts catalogue the part appears under the description Additional Shock Absorber F 313545, a name that misleads many buyers because the component holds no hydraulic parts at all. It is a polyurethane cushion that slides onto the piston rod of each front strut, above the dust boot, and it becomes the final cushion whenever the front suspension reaches full compression.

The part matters because a strut damper only controls wheel movement inside a fixed working range. A deep pothole, a fully loaded boot or a sharp speed bump can push the strut beyond that range. Without an intact bump stop, the piston rod strikes the top of the damper directly, seal wear accelerates and the well known hard knocking over rough roads follows. Renewing this low cost cushion during suspension work protects the far more expensive strut behind it.

Bonpora supplies the part under its own reference 4110127, moulded in polyurethane to the original profile: a 24.4 mm bore, a 67 mm outer diameter and a 70 mm height. The same piece fits the left and right side, and every car requires two.

Vehicle Compatibility: BMW 5 Series E60 and E61

The application note in the BMW catalogue for 31336764086 is explicit: without all wheel drive, without M5, with sport suspension. This is the sport suspension version of the E60 front bump stop, and it applies to rear wheel drive models only. Independent catalogues based on TecDoc data, such as the febi bilstein listing for this OE number, cover the complete E60 and E61 engine range from mid 2003 to the end of 2010, from the 520d with 150 hp up to the V8 saloons with more than 360 hp.

Two boundary cases deserve attention. First, the note excludes the M5, yet some independent catalogues still list the M5 engine among the applications, because TecDoc groups the E60 saloon as one body family. The M5 uses its own suspension setup, so buyers should confirm the exact car against the VIN before ordering. Second, all wheel drive 525xi, 528xi, 530xi and 535xi models are excluded and carry their own front bump stop numbers.

How to Confirm the Sport Suspension Version

Because the standard suspension variant of the E60 uses a different front cushion, confirming the suspension package matters more than confirming the engine. The quickest route is the factory build sheet or a VIN decode report, where the sport suspension option commonly appears under the option code 2WA. A visual check helps as well: sport suspension cars sit visibly lower, respond more firmly over bumps and usually carry shorter, thicker spring wire. When doubt remains, remove the old buffer and compare its height, bore and outer diameter with the drawing data in this article.

Technical Specifications of Bonpora 4110127

Aftermarket catalogues quote slightly different figures for the same OE number. febi bilstein 26178 records a thickness of 70 mm and a weight of 67 g, while Birth 54373 lists a height of 71 mm and a bore of 23.5 mm. These gaps come from different measuring points, for example overall height with the mounting lip versus bare cushion height, and from tolerances at the bore opening. Buyers should confirm orders against the dimensional drawing rather than against catalogue figures alone.

Distinguishing 31336764086 from Related BMW Numbers

BMW front bump stops share a similar silhouette across many platforms, so the number on the old part, not the look of it, should drive the purchase decision.

For buyers who also serve newer BMW platforms, the front strut bump stop 31336861727 for the 2 Series Active Tourer, 3 Series G20 and X1 F48 generations is covered in a separate article on this site: BMW strut bump stop 31336861727.

Symptoms of a Worn or Collapsed Front Bump Stop

Because the cushion hides inside the dust boot, wear usually stays invisible until the strut comes apart. The following signs point to a buffer that has reached the end of its service life.

• A hard thud or knock from the front axle over sharp compressions, worse with passengers or luggage on board
• Rising damper seal wear, followed by an oil film on the strut body, after years of uncontrolled travel
• Powder, chips or missing sections on the old buffer once the strut is removed
• Harsher ride on broken surfaces, because the damper runs out of travel sooner than the designers intended

Most E60 cars now pass fifteen years on the road. The original cushions have absorbed millions of compression cycles and years of ozone exposure, so experienced workshops inspect or replace the buffer whenever a strut, a top mount or a spring is renewed anyway.

Installation Notes for the Front Strut Assembly

• The buffer slides onto the damper piston rod inside the dust boot, before the strut is refitted to the body
• Left and right use the identical piece; order two per car
• Inspect the top mount and the dust boot at the same time, since worn boots let grit destroy a new buffer quickly
• Tighten the piston rod nut to the torque given in the workshop manual and avoid impact tools on the rod
• A light smear of grease on the piston rod helps the cushion seat without twisting

Spring compression work on a MacPherson strut stores significant energy and belongs in the hands of a trained technician with proper tools.

Aftermarket Cross Reference Numbers

Buyers who source through European wholesale channels will meet this OE number under several independent brand references.

All of the references above map to OE 31336764086. Brand packaging and quoted dimensions vary slightly, so match by application and by the dimensional drawing when in doubt.

Why Polyurethane for This Component

BMW specifies a polyurethane elastomer for this cushion, and Bonpora moulds 4110127 in the same material family.

No material removes the need for correct sizing and correct suspension identification. Polyurethane simply holds the designed cushion curve longer under heat, ozone and repeated compression, which is why most independent producers have moved their bump stop ranges in this direction. A wider overview of the material is available in the polyurethane bump stops section.

OEM Supply and Custom Manufacturing from Bonpora

Bonpora manufactures polyurethane suspension buffers and rubber to metal parts for distributors, importers and workshop chains. Standard references such as 4110127 ship in neutral export packaging with a one year warranty, within a 15 to 30 day delivery window. For programmes beyond the catalogue, the engineering team works from a drawing, a sample or simply an OE number, adjusting bore, outer diameter, height and compound hardness to the application. The custom parts page shows typical projects.

Planning a bulk order or a private mould for 31336764086? Send the OE number, your drawing or a sample, together with the target quantity, and the Bonpora team will reply with a quotation and a production schedule. Buyers who need more chassis references can browse the dedicated chassis and suspension category.

Frequently Asked Questions

Which cars does BMW 31336764086 fit?

It fits rear wheel drive BMW 5 Series E60 saloons and E61 Touring models with factory sport suspension, built from mid 2003 to late 2010. The engine range spans the 520i to 550i petrol versions and the 520d to 535d diesel versions. All wheel drive xi models and the M5 are excluded and carry their own numbers.

Is 31336764086 the same as 31336764085?

No. Catalogue data places 31336764085 on other applications, for example the front axle of the X1 E84. The two cushions differ in dimensions and suspension specification and should not be swapped. Always order by the number found on the old part or by a VIN based catalogue check.

Can a standard suspension buffer be used on a sport suspension E60?

It is not advisable. The standard and sport cushions differ in height and stiffness, so the wrong version changes the available damper travel and the point at which the front axle bottoms out. Fitting the version that matches the factory suspension keeps the ride and safety behaviour as intended.

Does Bonpora produce custom polyurethane bump stops?

Yes. Bonpora offers OEM and custom design support for polyurethane buffers, working from drawings or samples and adjusting size and hardness to the application. Standard references ship in 15 to 30 days in neutral export packaging, and custom mouldings follow an agreed project schedule.