Replacing the cheek plates on a jaw crusher is an essential maintenance procedure that safeguards the machine’s structural integrity and optimizes operational efficiency. These durable wear liners serve as protective barriers for the side frames, absorbing impact forces and abrasion while facilitating smooth material flow through the crushing chamber. Timely replacement is crucial to prevent accelerated wear of critical components.
This step-by-step guide details the proper procedure for executing cheek plate replacement with optimal safety and efficiency.
Also Read: What Does A Cheek Plate Do In A Jaw Crusher?
Safety Precautions Before Replacing Cheek Plates
Lock Out/Tag Out (LOTO) the Crusher
Ensure the machine is completely de-energized before accessing the cheek plates. Disconnect power and lock out all electrical controls.
Wear Proper PPE
Use gloves, safety goggles, a hard hat, and steel-toe boots to protect against metal fragments and falling debris during cheek plate removal/installation.
Use Lifting Equipment
Due to their substantial weight, cheek plates require mechanical handling—always use an overhead crane or forklift with rated slings.
Inspect Tools & Work Area
Verify that cheek plate removal tools (e.g., pry bars, impact wrenches) are in good condition, and the workspace is clear of tripping hazards or loose components.
Tools & Materials Required for Cheek Plate Replacement
Basic Tools:
Heavy-duty impact wrench or high-torque ratchet (capable of 500+ ft-lbs)
Hydraulic jack (for frame alignment if necessary)
Pry bars & tapered drift pins (for safe cheek plate extraction)
Calibrated torque wrench (to meet manufacturer’s bolt specifications)
Lifting Equipment:
Bridge crane or forklift (capacity ≥1.5x cheek plate weight)
Nylon slings or load-rated lifting chains (fitted with protective sleeves to prevent liner damage)
Replacement Parts:
Pre-machined manganese steel cheek plates (OEM or certified equivalent)
Grade 8.8 or higher fasteners (replace if original bolts show thread wear)
Lubricants & Sealants:
Copper-based anti-seize compound (for bolt threads and taper seats)
Molybdenum disulfide grease (for frame contact surfaces and adjustment wedges)
Step-by-Step Cheek Plate Replacement Process
Step 1: Prepare the Crusher
Fully Retract the Moving Jaw – Adjust to the maximum open position (measured per manual specifications) for safe access.
Purge the Crushing Chamber – Remove all residual material using an air hose or vacuum to prevent tool interference or debris ejection.
Install Temporary Supports (if required) – For large crushers, use fabricated stands or adjustable props to stabilize the moving jaw during disassembly.
Step 2: Remove Old Cheek Plates
Break Bolt Torque Gradually – Use an impact wrench with incremental torque settings to loosen bolts; apply penetrating fluid (e.g., PB Blaster) if corrosion is present.
Extract Plates with Controlled Force – Insert pry bars at designated fulcrum points (marked on the frame) and lift evenly. Never use flame-cutting or excessive impact on the plates.
Conduct a Failure Analysis – Document frame wear patterns with photos and check for fatigue cracks using NDT methods (e.g., dye penetrant).
Step 3: Clean & Inspect Mounting Surfaces
Abrasive Clean All Interfaces – Use pneumatic needle scalers or carbide scrapers to remove hardened debris from the frame and bolt holes.
Inspect Thread Integrity – Verify bolt holes with thread gauges; helicoil or oversize fasteners may be needed for damaged threads.
Apply Anti-Seize Compound – Liberally coat bolt threads and taper seats with high-temp nickel-based lubricant.
Step 4: Install New Cheek Plates
Pre-Fit Plates Without Fasteners – Confirm alignment by measuring gaps with feeler gauges before final installation.
Stage Bolts in Phases – Hand-tighten all bolts to 30% torque, then incrementally tighten to 50%, 80%, and finally 100% of specified value.
Follow OEM Torque Sequence – Adhere to the cross-pattern tightening diagram (typically provided in the manual) to avoid plate distortion.
Step 5: Final Verification
Calibrate Jaw Clearances – Adjust the toggle plate or hydraulic ram to achieve nominal CSS (Closed Side Setting) per the manual.
Execute a No-Load Test – Run the crusher at 10-20% rated speed for 5-10 minutes, monitoring vibration levels with a portable accelerometer.
Re-Torque After Thermal Cycling – Once the crusher reaches operating temperature, recheck all fasteners during scheduled downtime.
Common Mistakes to Avoid During Cheek Plate Replacement
1. Reusing Worn-Out or Non-Spec Bolts
Never reuse bolts that show thread deformation, necking, or corrosion pitting.
Always replace with OEM-specified grade bolts (e.g., ISO 8.8 or higher). Cheek plate bolts are critical load-bearing components!
2. Improper Torque Application
Avoid random tightening sequences—this warps cheek plates, causing asymmetric wear on jaw dies.
Use a calibrated torque wrench and follow the cross-pattern sequence in the manual.
3. Skipping Frame and Cheek Plate Seat Inspection
Check for hidden cracks, especially around cheek plate mounting lugs (use dye penetrant testing if suspected).
Reject new cheek plates if the backing surfaces show machining defects (e.g., >0.5mm warpage).
4. Ignoring Cheek Plate Fit-Up Before Final Torque
Verify flush contact between the plate and frame with a 0.05mm feeler gauge—gaps promote material buildup and accelerated wear.
Do NOT force misaligned plates into position with bolt tension—rework the seating surface first.
5. Neglecting Post-Installation Checks
Re-torque all bolts after 24 hours of operation—manganese steel cheek plates settle under cyclic loading.
Monitor uneven wear patterns (e.g., top-biased abrasion suggests incorrect CSS setting).
6. Using Incorrect Tools for Extraction
Never hammer directly on cheek plates—use tapered hydraulic pullers or induction heaters for stuck plates.
Pry bars must engage only at OEM-approved lift points (marked on the frame).
Maintenance Tips to Extend Cheek Plate Life
Rotate Plates Strategically
Only applicable to double-sided reversible plates—flip them at 50-60% wear depth (measured from OEM wear lines).
Do NOT rotate if plates show cracks or severe spalling—replace immediately to avoid catastrophic failure.
Monthly Wear Inspections with Jaw Dies
Measure wear depth using profile gauges or laser scanners, comparing against OEM’s maximum allowable wear (typically 30% of original thickness).
Check for abnormal wear patterns (e.g., uneven top/bottom wear suggests incorrect CSS or feed gradation issues).
Use Premium Manganese Steel (14-18% Mn Content)
Avoid non-standard substitutes—cheek plates must match the jaw dies’ hardness (180-220 HB for balanced wear).
Specify impact-tested alloy with Charpy V-notch ≥50 J for high-abrasion applications (e.g., granite, quartzite).
Optimize Feed Material & Crusher Settings
Avoid oversized feed (>80% of inlet width)—it accelerates cheek plate wear at the upper edges.
Maintain correct CSS (Closed Side Setting)—improper adjustment causes sidewall scraping and premature wear.
Control Material Buildup
Clean cheek plate backs weekly—accumulated fines create hot spots and uneven pressure distribution.
Apply dry graphite lubricant on mounting surfaces to reduce galvanic corrosion between steel and manganese.
Temperature Monitoring
Infrared thermography during operation—localized overheating (>120°C) indicates binding or misalignment.
Post-Shutdown Protocol
Loosen bolts gradually after crushing abrasive materials—thermal contraction can warp plates if left fully torqued.
Final Thought
Proper cheek plate replacement ensures smooth crusher operation, prevents frame damage, and maintains optimal crushing efficiency. By following these steps—along with regular maintenance—you minimize unexpected downtime and prolong machine life.
Contact us to get specifications and latest quotes for jaw crusher cheek plates.
