A demolition contractor in Frankfurt was on day 3 of a high-rise concrete demolition project using a Liebherr LB 44 high-reach attachment on a modified R960 base machine. The high-reach boom was at 44-meter extension, demolishing at the 12th floor, when the operator reported unusual cab vibration that wasn’t present at lower reach positions. The site engineer called a stop for inspection. The source: two of the six cab isolation mounts had fractured internally. The high-reach boom at maximum extension creates larger moment forces on the base machine than the base excavator was originally designed for — and the cab mounts, already at 3,200 hours, couldn’t handle the additional cyclic loading from the high-reach boom’s resonance at full extension. Replacement of all six mounts: €480. Avoiding continuation with failed mounts (potential cab movement that could affect operator control): the correct decision.
Demolition work subjects equipment to the most extreme mechanical inputs in the construction industry — continuous impact from hydraulic breakers and shears, full-amplitude swings to maximum reach, and sudden load releases as structures collapse. The rubber components throughout demolition machines must absorb these extreme inputs continuously while protecting operators, hydraulic systems, and the base machine’s structural integrity.
This guide covers rubber parts for high-reach demolition equipment, demolition excavators with shear and pulverizer attachments, and the base machine modifications that demolition applications require.
Need demolition equipment rubber mounts? Request a quote from Babacan Group — we supply rubber isolation components for demolition equipment across all major base machine brands.
High-Reach Boom System Rubber Components
High-reach demolition machines (also called high-demolition or super-reach excavators) add extended boom sections to standard base excavators, reaching up to 60+ meters. These machines are fundamentally different from standard excavators in the loads they create.
High-Reach Boom Joint Rubber Cushions
At each boom section joint in a high-reach assembly, rubber cushions absorb the bending and torsion loads as the boom moves between sections:
- Joint face cushions: Distribute the contact stress at each boom section mating face during work cycles
- Pin cushion bushings: At the pivot pin that connects boom sections, rubber-lined bushings allow slight angular movement
- Travel stop cushions: Limit the angular range between boom sections and absorb the impact of reaching the travel limit
These cushions are under exceptionally high loading at full extension because a small force at the attachment end creates a large moment at the base — the boom acts as a long lever. Joint cushion specifications for 44-meter class high-reach equipment typically require Shore A 65-80 to resist the compressive loads from boom moment reactions.
Slewing Ring Rubber Seals for High-Reach Bases
Base machines modified for high-reach use see significantly higher slewing ring loads than standard excavators — the larger boom assembly moment creates more bending force on the slewing ring. The rubber seals protecting the slewing ring:
- Must maintain sealing against the dust and concrete debris generated by demolition
- Are exposed to more frequent heavy loading cycles than standard excavation work
- Require inspection every 1,000 hours rather than the 2,000-hour interval appropriate for standard excavators
For additional context on crane and lifting equipment rubber sealing systems, see our crane rubber parts and vibration isolation guide.
Hydraulic Breaker Integration Rubber
Demolition excavators fitted with hydraulic breakers (hydraulic hammers) for concrete breaking face the most intense rubber component stress in any equipment category.
Breaker Mounting Bracket Rubber
The hydraulic breaker attaches to the excavator’s quick-attach or direct-mount bracket. Between the breaker and the bracket mounting surface, rubber isolation pads:
- Reduce hammer-impact vibration transmission to the excavator arm
- Protect the quick-attach mechanism from fatigue cracking
- Allow the breaker to self-align to the work face
For complete specifications on hydraulic breaker rubber components including chisel bushings, accumulator membranes, and mounting pads, see our comprehensive hydraulic breaker rubber parts guide.
The key rule for demolition excavator breaker work: replace breaker mounting rubber every 500-800 hours of active breaker operation. Breaker mounting rubber accumulates fatigue much faster than equivalent rubber in standard excavation work.
Excavator Arm Anti-Vibration Mounts for Breaker Work
When a demolition excavator works with hydraulic breakers for more than 50% of its operational time, the standard excavator arm and boom rubber components are insufficient. Demolition-spec machines use upgraded isolation mounts:
- Boom cylinder cushions: Higher-rated bump stops to absorb breaker recoil that loads the boom cylinder at top stroke
- Dipper arm wear pads: Reinforced rubber wear pads at the dipper arm contact points that see repeated impact during breaker work
Shear and Pulverizer Attachment Rubber
Demolition shears (concrete crushers, steel shears, pulverizers) create different loads than hydraulic breakers — high force, lower frequency, with peak loads during jaw closure rather than continuous impact.
Shear Jaw Cushion Rubber
Inside the shear jaw mechanism, rubber cushions absorb the closing impact when the jaws contact the material being processed. These cushions:
- Must survive the full crushing force of the shear jaw (typically 800-2,000 kN for a primary demolition shear)
- Allow slight misalignment between the upper and lower jaw as irregular material is crushed
- Compound: High-durometer NR or polyurethane, Shore A 70-85 for primary jaw applications
Jaw cushion service life is directly related to the hardness of material being processed — concrete with high aggregate content wears jaw cushions 2-3× faster than plain concrete. Track the material type in the service log to predict when jaw cushion replacement is approaching.
Attachment Rotation Motor Rubber
Most demolition shears and pulverizers include a rotation motor that allows the attachment to be rotated 360° for optimal positioning. The rotation motor seals:
– Must resist hydraulic oil contamination from concrete dust infiltration at the attachment bracket
– High-cycle application: The attachment may be rotated 20-50 times per hour during active demolition
Pulverizer Jaw Rubber Lining
Some concrete pulverizers use rubber-lined jaw faces in addition to the hard metal crushing surfaces. The rubber lining:
– Grips irregular concrete sections for better crushing efficiency
– Reduces concrete ejection during crushing (a site safety benefit)
– Compound: Abrasion-resistant NR, Shore A 55-70
Base Machine Rubber Components for Demolition Duty
Demolition work subjects the base excavator to loads significantly higher than its standard specification. This means rubber components wear faster and may require specification upgrades.
Engine Mount Upgrades for Heavy Demolition
Standard excavator engine mounts are designed for excavation work loads. When an excavator is used full-time for demolition with hydraulic breakers:
- Impact loading from the breaker creates higher-frequency, higher-amplitude engine mount excitation
- The combined breaker impact frequency (60-80 Hz typical) and engine vibration creates a wider frequency range that the mounts must attenuate
- Standard mounts may show 40-50% shorter life in heavy breaker applications
Demolition-specification engine mounts use a slightly higher durometer compound (Shore A 50-60 vs. 45-50 for standard excavation) to resist the breaker-induced amplitude excitation while maintaining adequate compliance for lower-frequency engine vibration.
Cab Isolation Upgrades
The Frankfurt high-reach case demonstrated the consequence of standard cab mounts failing under exceptional demolition loads. For machines used in continuous demolition work, cab mounts should be upgraded to the next higher load rating from the standard excavator specification.
For standard vibration isolation principles and how to select the correct mount specification for a given load and excitation frequency, see our anti-vibration mount selection guide.
The EU Vibration Directive exposure limits for demolition machine operators are frequently challenged — hydraulic breaker operators are among the highest-exposure construction workers. Maintaining cab isolation in specification is the primary controllable variable.
Rubber Components for Demolition Support Equipment
Wrecking Ball Crane Rubber
Traditional wrecking ball demolition (still used for some applications) uses crane rigging with rubber stop cushions at the crane boom tip to limit pendulum oscillation at the end of the swing:
– Rubber compound: High-energy absorption, Shore A 45-55
– Designed for high-energy impacts: The wrecking ball pendulum stores significant kinetic energy that must be absorbed at the end of each swing
For context on crane rubber components across the full range of crane types, see our crane rubber parts and vibration isolation guide.
Material Handler Rubber Components
Demolition material handlers (sorting crabs, orange peel grabs, grapples) use rubber seals in the hydraulic grab cylinder and wear pads at the grab jaw contact points. These wear pads:
- Reduce noise from metal-on-metal grab jaw closure (important in urban demolition environments)
- Compound: Abrasion-resistant NR, Shore A 60-70
Shore Hardness Monitoring Protocol for Demolition Equipment
Given the accelerated rubber wear in demolition applications, a systematic hardness monitoring approach provides early warning of degradation:
- Baseline measurement: Record Shore A of all key mounts when new
- Quarterly check: Measure all safety-path and high-use mounts
- Action threshold: When any mount exceeds nominal +10 Shore A, plan replacement
- Replacement threshold: Nominal +15 Shore A OR visible cracking, whichever comes first
This schedule (quarterly, not at machine hours) accounts for the fact that demolition machines may accumulate work hours faster than calendar time would suggest.
Babacan Group manufactures demolition equipment rubber components under ISO 9001:2015 quality management. Our range covers high-reach boom joint cushions, demolition shear jaw rubber, cab isolation mounts for heavy demolition, and breaker mounting pads for all major demolition excavator base machines (Liebherr, CAT, Hitachi, Volvo, Komatsu). Browse our rubber mounts catalog or request a technical quote.
Replacement Intervals: Demolition vs. Standard Excavation
| Component | Standard Excavation | Heavy Demolition |
|---|---|---|
| Engine mounts | 4,000-6,000 hrs | 2,500-3,500 hrs |
| Cab isolation mounts | 3,000-5,000 hrs | 1,800-2,500 hrs |
| Breaker mounting pads | N/A | 500-800 breaker hours |
| High-reach joint cushions | N/A | 2,000-3,000 hrs |
| Slewing ring seals | 2,000 hrs inspection | 1,000 hrs inspection |
| Shear jaw cushions | N/A | Material-dependent (500-2,000 hrs) |
Conclusion
Demolition equipment puts every rubber component to a higher test than standard excavation or construction work. High-reach machines create boom moments that challenge base machine cab mounts in ways that weren’t anticipated in standard excavator design. Continuous breaker work accelerates engine mount fatigue. Demolition shear jaw cushions survive only as long as the material being processed allows.
Key takeaways:
– High-reach boom use increases cab mount loading beyond standard excavator design parameters — inspect and upgrade cab mounts for high-reach applications
– Breaker mounting rubber is a 500-800 hour consumable in full-time breaker applications, not a standard excavator maintenance item
– Demolition shear jaw cushion life is material-dependent — track concrete aggregate hardness to predict replacement timing
– Shore A monitoring on a quarterly calendar basis (not just hourly basis) catches heat-aging degradation that hour-based schedules miss
Babacan Group ships demolition equipment rubber parts to demolition contractors and equipment rental companies in 84+ countries. Request a technical quote for your specific machine and attachment configuration.