Bomag Back-Up Ring | Part 05800845

The Bomag 05800845 Back-Up Ring is a genuine OEM component designed for a wide range of Bomag single drum rollers, tandem rollers, cold milling machines, and recycler/stabilizers — including BW 100, BW 120, BW 151, BW 174, BW 202, and BW 212 series machines, BM 1200/30 and BM 1300/30 cold milling machines, and MPH 121 and MPH 122 recycler/stabilizers. Sourced directly from Bomag, this back-up ring matches the original part in material, geometry, and sealing performance. It installs as a direct replacement using the original mounting configuration, keeping hydraulic and fluid circuits properly sealed across the full scope of compatible equipment. For contractors and equipment managers running mixed Bomag fleets, part number 05800845 provides consistent, OEM-verified sealing across an extensive range of machines.

Key Features

• Genuine OEM Sealing Integrity — manufactured to Bomag's original material and dimensional specification, ensuring this back-up ring delivers consistent compression and resistance to extrusion under operating pressure
• Broad Fleet Coverage — fits BW-series single drum and tandem rollers across multiple generations, BM 1200/30 and BM 1300/30 cold milling machines, and MPH 121 and MPH 122 recycler/stabilizers
• Direct OEM Replacement — matches the original geometry exactly, allowing this back-up ring to seat correctly in its groove without shimming, trimming, or adaptation
• Hydraulic Circuit Protection — a properly seated back-up ring prevents seal extrusion and fluid bypass, maintaining system pressure and protecting adjacent seals and components from premature wear
• Fluid Compatibility Assurance — manufactured from materials specified for Bomag hydraulic environments, this ring resists degradation from hydraulic fluid exposure over extended service intervals

A back-up ring is a rigid or semi-rigid support ring installed behind a primary O-ring or hydraulic seal. Its purpose is to prevent the softer primary seal from being pushed, or extruded, into the clearance gap between mating components when the system is under pressure. Without a correctly fitted back-up ring, the primary seal can deform and fail, leading to fluid leaks, pressure loss, and damage to the hydraulic circuit. Replacing a worn or missing back-up ring promptly is essential to maintaining the integrity of the sealing assembly and preventing costlier secondary damage.

Part Details

Compatibility & Fitment

Verify Before You Order

Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.

Why Buy From DHS Equipment

Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.

Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.