BOMAG Cab Mount Replacement Guide

Step 1: Diagnosing Worn BOMAG Cab Mounts

BOMAG cab mounts on BW series compactors typically require inspection every 500–1,000 operating hours. Early signs of wear include:

• Increased operator vibration: If the BOMAG operator notices higher vibration levels than normal, especially at drum operating speed, cab mount degradation is a likely cause
• Cab movement: Excessive lateral cab movement when the compactor steers or when the operator shifts weight
• Visual rubber cracking: Surface cracks, chunking, or permanent deformation visible on the rubber element
• Metal-to-metal contact: Audible clicking from cab mount area during operation indicates complete rubber failure
• Hydraulic lines under tension: Cab-mounted hydraulic lines may show signs of stress if the cab has dropped due to mount failure

Step 2: Selecting the Correct Shore A Hardness

BOMAG BW series cab mounts (3128 0458 series) are available in three Shore A hardness values. The selection depends on your specific application:

• 3128 0458 15 (15 Shore A — Soft): Maximum vibration isolation. Recommended for asphalt compaction where drum frequencies are highest (50–67 Hz). Operator comfort priority.
• 3128 0458 18 (18 Shore A — Medium): Factory standard for most BW series models. Balanced isolation and stability for both soil and asphalt compaction.
• 3128 0458 24 (24 Shore A — Firm): Stability priority. Use for slope compaction, rough terrain, or when the cab moves excessively with the medium compound.

If in doubt, consult the BOMAG BW series spare parts manual for your specific model and serial number range, which specifies the factory-fitted hardness. Contact our technical team with your machine serial number for hardness confirmation.

Step 3: Installation Procedure

1. Lower the cab: Follow BOMAG's cab lowering procedure in the operator manual. Do not work under a raised cab without proper blocking.
2. Mark the mount orientation: BOMAG cab mounts may be directional. Mark the existing orientation with paint before removal.
3. Remove fasteners: Record torque values from the BOMAG service manual. Typically M12 or M14 bolts with specified torque in the 70–120 Nm range.
4. Clean mounting surfaces: Remove rust, old rubber debris, and corrosion from the frame and cab mounting pads. The mating surfaces should be flat within 0.5 mm.
5. Install new mounts: Use the same orientation as the removed mounts. Do not over-tighten as this can compress and damage the new rubber.
6. Torque fasteners: Use a calibrated torque wrench. Tighten in cross-pattern sequence to achieve even load distribution.
7. Post-installation check: Inspect cab height and alignment. The cab should sit level with equal compression on all mounts. Run the BOMAG at low drum speed and check for unusual noise or vibration.

Replacement Intervals

BOMAG recommends cab mount inspection at 500-hour intervals and replacement when any of the diagnostic criteria above are met. For high-intensity asphalt compaction work, replacement intervals may be as short as 1,000–1,500 hours. For lighter-duty soil compaction, mounts may last 3,000+ hours before performance degradation becomes significant.

Maintaining a stock of 4–8 replacement mounts (one full set plus a spare) at the job site prevents unexpected downtime when inspection reveals worn mounts.

BOMAG Cab Mount Part Numbers for BW Series

Key BOMAG BW series cab mount part numbers:

• 3128 0458 15 — 15 Shore A soft
• 3128 0458 18 — 18 Shore A medium (factory default)
• 3128 0458 24 — 24 Shore A firm
• 3128045824 — Same as 3128 0458 24 (alternate numbering)
• 3115 1822 00 — BOMAG rubber buffer (specific positions)
• 3115 1822 01 — BOMAG rubber buffer Type-1 variant
• 3128259405 — Complete cab mount assembly