Construction Plant Fitting
Domain overview
Construction plant fitting is the assembly, installation, diagnosis, and repair of earthmoving, lifting, and concrete equipment. The exam tests whether you can apply fit and torque rules, keep hydraulic systems clean, isolate stored energy, and verify a repair against a specification rather than by feel.
Fits, fasteners, and alignment
Bearings are installed with controlled force on the interference-fit ring-usually the rotating ring-never by hammering the rolling elements. Interference fits may use an induction heater; check the temperature limit and allow controlled cooling. Clean and lubricate threads exactly as the torque table states: lubricated threads need lower torque than dry. Tighten cylinder heads and flanges in the specified sequence and stages. Check shaft alignment with a dial indicator or laser before coupling.
Hydraulic cleanliness and hose work
Cap open ports and fittings immediately. Match SAE dash size, pressure rating, bend radius, and end fitting; verify the crimp with the correct gauge. Flush or replace filter elements after a failure. Target an ISO 4406 cleanliness code stated in the manual. Pressure-test with a calibrated gauge and never search for leaks with a bare hand-use paper or a probe.
Isolation and verification
Apply lockout/tagout and release stored energy: accumulators, raised booms, pressure, and gravity. For lifting plant, verify SWL, sling condition, and test certification. After assembly, perform a function test, check for abnormal noise or heat, and record measurements.
Worked example
An excavator hose fails. Read the dash size and pressure rating from the parts book, not the old hose. Select a hose with equal or higher rating and correct bend radius, crimp a matching fitting, and confirm the crimp dimension. Cap the ports, replace the return filter, connect, torque to spec, bleed, then test at relief pressure and inspect for chafing.
Traps
Over-torquing a lubricated fastener; reusing a deformed seal; assuming a circuit is depressurized; fitting a hose with a tighter bend than allowed; using an uncalibrated torque wrench; and skipping the post-repair function test.