2021 Caterpillar 320 Bolt Sizes & Torque Specs

Free OEM-referenced torque and bolt specs for the 2021 Caterpillar 320.

This page is the OEM-referenced fastener summary for the 2021 Caterpillar 320. Use it before any maintenance or repair job where torque values matter — brake work, wheel changes, suspension service, engine teardowns, or oil changes. Specs are pulled from manufacturer service literature, cross-checked against community data, and updated as new chassis variants become available.

For the 2021 Caterpillar 320, fasteners follow metric standards typical of late-model Caterpillar engineering. Always confirm spec against the factory service manual before tightening safety-critical fasteners (suspension, brake, steering, head bolts).

Common fastener categories on the 2021 Caterpillar 320

Wheel / lug nut torque and thread spec (covered above)
Brake caliper bracket bolts (typically 80-130 ft-lbs) and slide/guide pins (18-35 ft-lbs)
Engine oil drain plug torque — rarely above 30 ft-lbs; always use a new crush washer
Transmission pan, valve cover, and intake manifold bolts (low torque, often 89-106 in-lbs)
Suspension control arm, sway bar, tie rod end and ball joint torque
Spark plug torque (typically 10-15 ft-lbs on aluminum heads — do not exceed)
Differential cover bolts (RWD/4WD only) and transfer case fasteners

Repair guidance for this model year

For 2021 late-model work: Modern vehicles increasingly use aluminum body and suspension components. Aluminum fastener torque is typically 60-70% of equivalent steel torque, and aluminum threads strip easily. Use a calibrated torque wrench and apply anti-seize on any steel fastener threading into aluminum.

Tools you will need

Metric socket set (8mm-22mm), 6-point impact-rated
Calibrated torque wrench (10-150 ft-lbs covers most automotive jobs; add a 0-250 ft-lbs wrench for truck lug nuts)
Breaker bar (24" minimum) for initial loosening
Penetrating oil (PB Blaster or Kroil) for any fastener over 5 years old
Anti-seize on stainless or dissimilar-metal threads; thread-locker (Loctite blue) on critical reassembly

Frequently asked questions

What is the lug nut torque on a 2021 Caterpillar 320?

Manufacturer-specified torque values for the 2021 Caterpillar 320 are in the factory service manual or owner's handbook. WhatSizeBolt sources values from manufacturer literature and verifies against community data — if we do not have this exact year listed, check the Caterpillar brand page for the closest model year.

What socket size do I need for the 2021 Caterpillar 320 lug nuts?

Most modern Caterpillar vehicles use a 19mm or 21mm socket. Older Caterpillar models from before 2000 may use a 13/16" SAE socket on certain trims. Confirm against the actual lug before purchasing aftermarket wheels.

Are the 2021 Caterpillar 320 fasteners metric or SAE?

Metric is the standard for this vehicle. Most fasteners on this vehicle are metric (M6, M8, M10, M12, M14). Bring a full metric set; SAE substitutes can round the head. Bolt-head markings are the fastest way to confirm grade and material at the bench.

Other Caterpillar 320 years

Same model, different model year — fastener spec may change. Always confirm against the year for your VIN.

→ 2021 Caterpillar 320 oil drain plug torque & size

→ 2021 Caterpillar 320 engine & transmission mount torque specs

All 15 2021 Caterpillar 320 fastener specs

Per-bolt torque, wrench size, and thread spec for the 2021 Caterpillar 320, sourced from OEM service literature and verified against community shop data. Values pair imperial (ft-lb) and metric (Nm) where the manufacturer publishes both.

engine — 2021 Caterpillar 320

Engine bolt-by-bolt torque for the 2021 Caterpillar 320, including the long block, valve covers, and intake. plan for a M8 tool on a M8x1.25 stud; final torque is 10 Nm / 7 ft-lbs (air filter housing clamp bolt). Fuel filter housing bolt tightens to 22 Nm / 16 ft-lbs, takes a M8 driver, runs on M8x1.25 threads. The engine mount bolt (rear) uses a M16 drive on a M16x2.0 thread, torqued to 220 Nm / 162 ft-lbs. The engine mount bolt (front) torques to 220 Nm / 162 ft-lbs (M16 drive, M16x2.0 thread). plan for a M22 tool on a M22x1.5 stud; final torque is 70 Nm / 52 ft-lbs (engine oil drain plug).

undercarriage — 2021 Caterpillar 320

undercarriage fasteners on the 2021 Caterpillar 320. Sprocket mounting bolt tightens to 490 Nm / 361 ft-lbs, takes a M20 driver, runs on M20x2.5 threads. The idler recoil spring nut uses a M36 drive on a M36x3.0 thread, torqued to 750 Nm / 553 ft-lbs. The track shoe bolt torques to 490 Nm / 361 ft-lbs (M20 drive, M20x2.5 thread). plan for a M12 tool on a M12x1.75 stud; final torque is 98 Nm / 72 ft-lbs (final drive cover bolt).

attachment — 2021 Caterpillar 320

attachment fasteners on the 2021 Caterpillar 320. The boom foot pin retainer bolt uses a M16 drive on a M16x2.0 thread, torqued to 220 Nm / 162 ft-lbs. The bucket link pin retainer bolt torques to 78 Nm / 57 ft-lbs (M12 drive, M12x1.75 thread).

hydraulics — 2021 Caterpillar 320

hydraulics fasteners on the 2021 Caterpillar 320. The hydraulic oil drain plug torques to 120 Nm / 89 ft-lbs (M30 drive, M30x2.0 thread). plan for a M16 tool on a M16x2.0 stud; final torque is 185 Nm / 136 ft-lbs (swing motor mounting bolt). Control valve mounting bolt tightens to 47 Nm / 35 ft-lbs, takes a M10 driver, runs on M10x1.5 threads. The hydraulic pump mounting bolt uses a M12 drive on a M12x1.75 thread, torqued to 78 Nm / 57 ft-lbs.

New to torquing wheels? Read our How lug nut torque works — the complete guide for star-pattern sequence, re-torque intervals, and how to read a lug spec — then use the 2021 Caterpillar 320 numbers above.

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