How to replace worn jaw plate of jaw crusher step by step

1. Preparatory Work

Shut down the crusher completely, cut off the main power supply, hang lockout & warning signs to prevent accidental startup.
Release the tension spring and toggle plate tension assembly.
Prepare tools: spanners, hydraulic jack, crowbar, hoist / lifting sling, copper hammer, grease, new jaw plates, protective gloves, safety helmet, goggles.
Clean the outer surface of the crusher, remove dust and residual ore around the crushing chamber.
Confirm the new jaw plate model, tooth direction and size match the old one. Check for casting defects.

Remove the upper and lower fastening bolts of the fixed jaw plate.
Use a copper hammer and crowbar to loosen the jaw plate slowly.
Lift the worn fixed jaw plate out with hoisting equipment.
Clean the contact surface of the jaw frame thoroughly, remove old back filler (zinc alloy / cement filler), rust and debris.

Take out the toggle plate first, then release the hold-down bolts and wedge blocks of the movable jaw plate.
Pry the movable jaw plate loose carefully.
Lift the worn movable jaw plate out.
Clean the surface of the movable jaw stock; check the jaw stock for crack, deformation or thread damage.

Tip: If the jaw plate is still stuck tightly, use a hydraulic jack for auxiliary pushing; never hit the jaw stock hard.

Check toggle plate, toggle seat, tension spring, spring rod, wedges and bolts. Replace cracked, deformed or fatigued parts.
Check the back support surface of fixed jaw and movable jaw stock, ensure flat without pits.
Inspect all bolt threads; repair or replace damaged threads.

Hoist the new fixed jaw plate into position, align it closely with the jaw frame contact surface.
Install wedge blocks and preliminary tighten fastening bolts.
Hoist the new movable jaw plate onto the movable jaw stock, align the positioning edge.
Install wedges and hold-down bolts, pre-tighten all bolts evenly in sequence (cross tightening).
Pour back filler (zinc alloy or special filler) between the back of jaw plate and jaw frame/jaw stock as required. The filler must fully fill the gap to ensure uniform force.

Important: The tooth crests of fixed jaw and movable jaw must stagger (tooth tip aligns with tooth valley), do not mesh tip-to-tip.

Install toggle plate back to the toggle seat, make sure both ends sit fully in the socket.
Reset tension spring and spring rod, adjust spring preload to the standard value (not too loose or over-tight).
Recheck all wedges and bolts again after filler solidifies. Carry out secondary tightening.

Clear all tools and sundries inside the crushing chamber.
Manually turn the flywheel by hand to test rotation; no jamming, scraping or abnormal friction.
Restore power, run the crusher under no-load condition for 10–15 minutes.
Monitor vibration, noise, temperature and bolt looseness during no-load test.
If everything works normally, start feeding small amount of material gradually for load test.

Do not stand in front of the crushing chamber during lifting and installation.
Do not weld or punch jaw plates randomly on site.
Replace jaw plates in pairs if wear is serious; single-side replacement will cause uneven force.
Re-tighten all bolts after the first 2–4 hours of formal operation, because filler and wedges may settle.