What you’re doing: removing, inspecting, and reinstalling the flywheel and associated clutch parts on a Toyota 2H / 12H‑T engine (manual-transmission vehicles). This tells you what every part is, why the job is needed, how the system works, what can go wrong, and a clear step‑by‑step procedure for a beginner mechanic. Follow factory service manual torque specs and procedures exactly for your vehicle — I won’t guess torque numbers.

Quick theory / analogy
- Flywheel: a heavy steel disc bolted to the back of the crankshaft. Think of it as a bicycle wheel with weight attached to the rim: it smooths engine pulses, stores rotational energy, and gives the starter something to turn (ring gear) and gives the clutch a friction surface to push against.
- Clutch: the interface between the spinning engine (flywheel) and the transmission input shaft. The clutch disc sits against the flywheel; the pressure plate presses the disc to the flywheel to transmit torque. When you depress the pedal a release bearing pulls on the pressure plate so the disc can spin freely and you can change gears.
- Why repair: common reasons to remove the flywheel include clutch replacement, flywheel resurfacing or replacement for wear/damage/warpage, replacing the rear main seal or pilot bushing, or fixing vibration/noise. If the flywheel surface is glazed, scored, cracked or oil‑soaked, the clutch will slip, chatter, or not disengage cleanly.

Components — what each piece is and why it matters
- Crankshaft flange: the back face of the crank where the flywheel bolts on. Must be clean and undamaged; bolts must seat solidly.
- Flywheel (single-mass): heavy disc with friction surface on one face. Provides inertia, mounting face for clutch, and ring gear around the outside for the starter. Can be resurfaced if within service limits; cracked or severely worn flywheels must be replaced.
- Ring gear: gear teeth pressed or welded onto the flywheel perimeter. Starter gear (pinion) engages these teeth to crank the engine. Broken teeth cause starter grinding or fail-to-engage.
- Dowel pins: small pins used to locate the flywheel precisely on the crank flange. They ensure correct alignment; if missing or loose, the flywheel can be misaligned.
- Flywheel bolts: high‑strength bolts that secure the flywheel. They must be replaced or reused per service manual and torqued in the correct pattern and stages. Failure → loose flywheel, catastrophic damage.
- Pilot bushing / pilot bearing: in the center of the flywheel/crank or in the crank nose; supports the transmission input shaft. If worn it causes misalignment, vibration, or difficulty shifting.
- Rear main seal: seals where the crank exits the block. If leaking oil onto the flywheel or clutch, contamination causes slipping and glazing. Often replace when flywheel is out.
- Clutch disc (driven plate): friction material riveted to a hub; splines ride the transmission input shaft. Has springs to dampen torsional shocks. Worn or oil‑contaminated discs will slip or shudder.
- Pressure plate: bolts to the flywheel and clamps the clutch disc. Uses either diaphragm spring or coil springs to apply clamping force. Warped or broken pressure plates cause chatter or slipping.
- Release (throwout) bearing: presses on the pressure plate’s fingers to release the clutch. Worn or seized bearings cause noise or failed disengagement.
- Clutch fork / pivot / hydraulic slave or cable: transfers pedal movement to the release bearing. If out of adjustment or worn, clutch operation suffers.
- Transmission bellhousing: covers the clutch and bolted to the engine; removal gives access to flywheel/clutch.
- Transmission input shaft: slides into the pilot bushing and clutch disc splines. If shaft or splines are damaged, clutch engagement is poor.

Tools and consumables (minimum)
- Factory service manual for your vehicle (torques, specs, removal order, clearances).
- Full socket set (including large sockets for flywheel bolts), breaker bar, ratchet.
- Torque wrench (capable of required bolt torques).
- Transmission jack (or a second jack and support) and engine support/engine hoist if needed.
- Pry bars, screwdrivers, hammer, punch.
- Clutch alignment tool sized to your gearbox pilot diameter.
- Flywheel ring‑gear puller (if removing ring gear) or heat/press for replacement.
- Cleaning solvent, lint‑free rags, wire brush.
- Thread locker (per manual) or new bolts if required. Anti-seize only where specified.
- Jackstands, wheel chocks, safety glasses, gloves.
- Replacement parts: new clutch disc, pressure plate, release bearing, pilot bushing (or bearing), rear main seal, new flywheel bolts if specified, possibly a new/replaced flywheel.
- Gauges/straightedge/feeler gauge for runout check; micrometer if checking thickness.

Safety first
- Work on level ground, block wheels, disconnect battery negative.
- Use jackstands under a solid lift point — never rely on a hydraulic jack only.
- Support engine if removing transmission; use transmission jack for the gearbox.
- Flywheel and clutch parts are heavy and can pinch — use helpers or hoist.

Step‑by‑step removal (generalized beginner-friendly process)
Follow factory manual for trim items, torque specs and wire/line routings.

1) Prep
- Disconnect battery negative.
- Raise vehicle and support on jackstands. Remove driveshaft(s) or propshaft, wheels as needed to access transmission. Drain gearbox fluid if necessary to avoid spills.

2) Remove components blocking transmission
- Remove starter motor (unbolt and hang aside). Mark wire locations.
- Remove shift linkage, speedometer or sensor connectors, any wiring or hoses attached to bellhousing.
- Disconnect clutch hydraulic line or release bearing cable; bench‑bleed the system if hydraulic is disconnected.

3) Support engine and transmission
- Support engine with jack/engine support if recommended.
- Support transmission with a transmission jack.

4) Unbolt and separate transmission
- Remove bellhousing bolts that attach transmission to engine. Keep track of bolt lengths/locations.
- Carefully slide transmission rearward; watch for input shaft clearing the clutch disc splines and pilot. Have helper or jack guide. Remove transmission and set aside on jack.

5) Remove clutch assembly
- Before unbolting pressure plate, mark relative orientation of pressure plate to flywheel if you want to reuse pressure plate balance or orientation (generally replace pressure plate and disc together).
- Loosen pressure-plate bolts gradually and evenly in crisscross pattern to relieve diaphragm pressure; remove bolts and pressure plate. Remove clutch disc. Note wear pattern on the disc.

6) Inspect and remove flywheel
- Inspect flywheel face. Look for scoring, blueing (overheating), cracks, or oil contamination. If doubtful, measure for runout and thickness against factory limits.
- If staying with same flywheel, mark bolt orientation if you want to reuse. If replacing, clean crank flange face.
- Remove flywheel bolts in a star pattern, gradually easing them out to avoid warping the crank face. Remove flywheel. Keep hands clear—flywheel is heavy.

7) Inspect pilot bushing, rear main seal, crank flange
- Check pilot bushing/bearing for wear; replace if rough or loose.
- With flywheel off you have access to the rear main seal — replace if leaking or if you are doing a clutch job (recommended).
- Inspect crank flange and dowel pins.

Flywheel inspection and machine/replace criteria
- Surface: light scoring may be machined (resurfaced) flat if within thickness limits and not cracked. Deep grooves, heat cracks, or missing ring gear teeth require replacement.
- Runout: mount flywheel on the crank and check radial runout with a dial indicator per manual. Excessive runout → resurface or replace.
- Thickness: measure and compare to minimum thickness in manual. If below limit, replace.

Installation (clean, measure, install)
1) Clean surfaces
- Clean crank flange and flywheel mounting face; no grease, oil, or dirt. Do not sand the friction surface with abrasives that leave grit.

2) Install rear main seal / pilot bushing
- Press in new rear main seal and pilot bushing per manual. Use correct drivers to avoid damage. Lubricate pilot bushing lightly if required.

3) Mount the flywheel
- Use dowel pins for location. Place flywheel against crank flange. Thread flywheel bolts by hand. Tighten bolts finger‑tight in a star pattern to seat the flywheel.
- Torque bolts in multiple stages (e.g., snug → mid torque → final torque) in a crisscross pattern. Use factory torque values. If bolts are specified as one‑time torque/stretch bolts, replace with new ones.

4) Check runout and final inspection
- After torquing, check flywheel runout per manual. If out of spec, remove and resurface or replace.

5) Install clutch assembly
- Position clutch disc so the side marked “engine” faces the flywheel (if marked); friction material orientation matters.
- Use the alignment tool through the clutch disc into the pilot bore to center the disc perfectly. Install pressure plate over the disc. Thread bolts finger-tight.
- Tighten bolts evenly in crisscross pattern in staged increments to final torque per manual. If clutch disc or pressure plate bolts are specified as single‑use, replace them.

6) Reinstall transmission
- Inspect input shaft splines for wear; clean and apply specified light lubrication if manual requires. Ensure release bearing is properly installed on the fork and that the fork pivot is intact.
- Carefully align transmission input shaft to clutch disc and pilot; slide transmission toward engine until bellhousing seats. Fasten bellhousing bolts in pattern specified. Reinstall starter, linkage, driveshafts, and any other disconnected items.

7) Final adjust and bleed (if hydraulic)
- Reconnect hydraulic line and bleed clutch system per manual (if hydro). Check clutch pedal free play / adjustment.
- Refill transmission fluid if drained.

Break-in and testing
- Start engine and test clutch engagement while vehicle is on stands: gently engage gears to ensure smooth operation.
- Do a short drive with moderate acceleration and clutch usage to seat the new surfaces — avoid hard launches for a few hundred kilometers/miles.

Common failure modes and how to spot/fix them
- Clutch slipping under load: usually glazed or oil‑contaminated disc, weak pressure plate, or wrong installation. Fix by replacing contaminated parts; find oil leak (rear main seal).
- Chatter/vibration on engagement: warped flywheel, uneven pressure plate, contaminated disc, or wrong disc orientation. Resurface or replace flywheel, replace clutch disc and pressure plate.
- Hard shifting or sticking: damaged pilot bushing, misaligned transmission input shaft, or worn release bearing/fork. Replace pilot bushing, inspect shaft and bearing.
- Starter grinding: missing/damaged ring gear teeth or starter mis‑aligned. Inspect ring gear and starter mounting.
- Loud knocking/loose flywheel: loose or broken flywheel bolts — VERY DANGEROUS. Always torque properly and replace bolts if required. If you find loosened bolts, inspect for crank flange damage and potential engine damage.

Notes, tips, and best practices
- Replace wear items as a set: clutch disc, pressure plate, release bearing, and pilot bushing are cheap relative to the labor to get there again. Replace rear main seal while the flywheel is off if leaking or if you’re doing a clutch job.
- Resurfacing: a properly resurfaced flywheel is flat and clean; machine shop must respect minimum thickness. Don’t overheat the flywheel or you’ll introduce cracks/warpage.
- Mark orientations as you disassemble to aid reassembly (but replace parts when recommended).
- Take pictures as you go for harness/line routing.
- Use a transmission jack and a helper for safety; the gearbox is heavy and awkward.

What I did not include
- Exact torque values, bolt grades, and minimum thickness/runout specs because those are model/year/serial‑specific — consult the Toyota factory service manual for your exact engine/transmission combination and serial number.

Summary
- The flywheel is critical for smooth power delivery and to give the clutch a proper friction surface. Remove the transmission, remove clutch, remove flywheel, inspect/measure/surface or replace, reinstall using new seals/parts as needed, torque bolts in stages, center the clutch with an alignment tool, reassemble and test. Replace worn parts and fix leaks. Follow the factory manual for all torque numbers and clearances.

Do this job methodically and safely, and when in doubt consult the factory manual or an experienced technician.
rteeqp73

Engine Bay, Wiring & Installing the 12HT - HJ75 Troopy Build (EP8) What is going on legends, Super stoked with today's episode, jam packed with a lot of good work. Follow along as we get stuck ...

2H to 12ht conversion 60 series Landcruiser HJ FJ60 Some information on doing an engine swap on your 60 series Landcruiser that you might find helpful. let me know if i can be of ...

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1) Purpose and theory (why rotate)
- Tires wear unevenly because each wheel position has different forces: steering wheels (usually front) scrub during turning and carry braking/steering loads; drive wheels carry propulsion torque; rear wheels often see different loads. This produces asymmetric tread loss (toe/shoulder wear, cupping).
- Rotation redistributes tires among positions so each tire experiences different loads over its life, averaging wear across all four tires. That increases usable life, preserves predictable handling/traction, and reduces noise/vibration from one overly‑worn tire.
- Rotation is a mitigative maintenance action, not a cure for mechanical faults. It corrects the symptom (uneven wear) by reassigning tire positions so overall tread depths equalize. If wear is caused by alignment, worn suspension, imbalance or improper pressure, rotation only evens the damage — the root cause must be fixed to stop recurrence.

2) Choose correct rotation pattern (theory + when to use)
- Front‑wheel drive (FWD): use the forward‑cross pattern — rear tires move straight to the front (same side); front tires move to the opposite rear positions. Rationale: fronts wear fastest; moving rears to front shares load and crossing fronts evens steering/side wear.
- Rear‑wheel drive / 4×4 (RWD): use the rearward‑cross pattern — front tires move straight back (same side); rears cross to the front. Rationale: rears carry drive torque; moving fronts back shares load.
- All‑wheel drive (AWD) or equal wear concern on all four: use the X‑pattern (every tire moves to the opposite axle and opposite side) to equalize.
- Directional tires (tread points one direction): only front‑to‑rear on the same side (no side swaps).
- Staggered sizes (different front/rear sizes) or one‑spare‑only: limited options; rotate only between like‑size positions or include the spare if full‑size and matched.

3) Practical ordered procedure (safety + theory notes inline)
1. Prepare: park on level ground, set parking brake, chock wheels. Rationale: prevents vehicle movement under lift.
2. Inspect tires: note tread depths, damage, bulges, nails, and correct pressures. Rationale: identify irreparably damaged tires or those indicating a root cause (e.g., feathering suggests alignment).
3. Loosen lug nuts slightly while wheels on ground (breaker bar). Rationale: prevents wheel spin while jacking.
4. Jack and support: lift at manufacturer jack points and install jack stands before removing wheels. Rationale: safe, stable support — do not rely solely on the jack.
5. Remove wheels and swap according to chosen pattern. Rationale: physically repositioning tires changes the forces each tire will see next.
6. Refit wheels, finger‑start lug nuts, lower vehicle to ground so tires seat, then torque lug nuts to manufacturer spec in a star/crisscross sequence. Rationale: even clamping avoids rotor distortion and ensures wheel security.
7. Set tire pressures to spec and check valve stems. Rationale: correct pressure equalizes contact patch and wear rate.
8. Road test and recheck: after 50–100 km, re‑torque lug nuts. Rationale: thermal cycling and seating can alter torque.
9. Document next rotation interval (typically every oil change / 5,000–10,000 km or manufacturer interval). Rationale: regular intervals prevent significant disparity in wear.

4) How the repair (rotation) fixes the fault, specifically
- Symptom: one or two tires are more worn than others (typically front shoulders, outer/inner edges, or cupping).
- Fix mechanism: by moving a heavily worn tire to a different position, rotation subjects it to different steering/drive/braking forces so other tires share the previously concentrated wear. Over successive rotations the wear pattern averages out and all four tires reach end of life closer together.
- Limits: rotation cannot correct wear caused by permanent geometry errors (toe/camber), failing components (bad shocks, loose ball joints) or imbalance. Those defects create ongoing abnormal wear; rotation only redistributes the effect and may temporarily reduce symptom severity but the pattern will reappear until the underlying fault is repaired.

5) Quick diagnostics that tell you rotation isn’t enough
- Inner/outer edge wear (excessive one side) → likely camber or incorrect toe: needs alignment.
- Feathering/stepped tread → likely excessive toe or worn steering parts.
- Cupping/scalloped tread → worn shocks/struts or imbalance.
- Rapid wear on drive wheels only → drivetrain or differential issues, or underinflation on those tires.

6) Final notes (concise)
- Always follow Toyota’s torque and jack point specs for your model/axle. If you don’t have the manual, record exact tire positions before swapping.
- Maintain correct pressures and check alignment/suspension if uneven wear recurs. Rotation prolongs tire life and restores balanced handling but is part of a preventive program, not a substitute for repairs.

Done.
rteeqp73