- Safety first
- Park tractor on level ground, set handbrake, remove ignition key, allow engine to cool completely before touching the cooling system.
- Wear safety glasses, chemical-resistant gloves, and old clothes; coolant is toxic and slippery.
- Have a drip pan or bucket and absorbent rags ready to catch spilled coolant; avoid draining into soil or storm drains — capture and dispose per local regulations.

- What the “expansion tank” is on a TE‑20 (short)
- The expansion/header tank is the small tank that sits above or beside the radiator and collects overflow/air from the cooling system; it is usually a simple metal or alloy tank with inlet/outlet hose(s) and a cap.
- If it is cracked, corroded, leaking at hose connections, or the cap no longer seals, it must be repaired or replaced to maintain system pressure and prevent air ingress and coolant loss.

- When replacement is required and what to replace
- Replace the expansion/header tank when you see visible cracks, heavy corrosion, internal rust perforation, or persistent leaks that cannot be sealed.
- Replace any rubber hoses that are soft, cracked, swollen, or hardened; old hose clamps that are rusted or slip should be replaced.
- Replace the radiator cap if it will not seal or the pressure spring is weak/rusted (its sealing is essential).
- Possible replacement parts: TE‑20 header tank (original style or reproduction), radiator cap (correct type for tractor), rubber hose sections (engine coolant rated), worm-gear hose clamps or screw clamps, mounting bolts if corroded, gasket/sealant if applicable.

- Tools you will need (detailed descriptions and how to use each)
- Adjustable spanner (adjustable wrench)
- Description: Single jaw wrench with screw to change jaw width; fits many bolt/nut sizes.
- How to use: Adjust jaw so it fits snugly on the nut/bolt flats, pull handle toward you (not twist wrench around loose jaw), avoid turning on damaged bolt heads; use to loosen/tighten nuts that sockets don't fit.
- Open-end wrenches (set, metric or imperial depending on TE‑20 fasteners)
- Description: Fixed-size wrenches with U-shaped ends sized to nut flats.
- How to use: Slip end over nut or bolt, apply steady force; use a size that fits tightly to avoid rounding the fastener.
- Socket set with ratchet (1/4" or 3/8" drive and appropriate sockets)
- Description: Ratchet handle and sockets to fit nuts/bolts; faster and gives better leverage.
- How to use: Choose socket that fits nut, place on ratchet, turn ratchet handle; use extension bars to reach recessed bolts; always pull the handle toward you for best control.
- Screwdrivers (flat/blade and Phillips)
- Description: Hand tools for slotted and cross-head screws.
- How to use: Use correct tip size; press firmly and turn; for clamp screw heads (worm clamps) use flat or Phillips as appropriate.
- Pliers (slip-joint or combination)
- Description: Two-jaw pliers with adjustable pivot for gripping and twisting.
- How to use: Grip hose or clamp to bend or hold; do not use pliers as a replacement for wrenches on nuts (they can round them).
- Hose clamp pliers or long-nose pliers
- Description: Pliers suited to squeeze and reposition spring or screw-style hose clamps.
- How to use: For spring clamps squeeze and move clip away from hose end; for screw/worm clamps use long-nose to hold while turning screw with screwdriver.
- Putty knife or gasket scraper / wire brush
- Description: Stiff blade to clean gasket surfaces and remove corrosion; wire brush cleans threads and metal surfaces.
- How to use: Gently scrape old sealant or flaky corrosion; brush rust and dirt from mating surfaces; avoid gouging sealing surfaces.
- Bucket/drain pan and funnel
- Description: Container to catch drained coolant and funnel to refill without spills.
- How to use: Position pan beneath drain points, use funnel to pour coolant back cleanly.
- Replacement hose(s) and clamps
- Description: Coolant-rated rubber hose, sized to fit the tank and radiator fittings; worm-gear or spring clamps.
- Why needed: Old hoses and clamps are common failure points and should be renewed when tank is replaced.
- Rags and absorbent pads
- Description: For cleanup of spills and wiping parts.
- How to use: Catch drips, clean surfaces before assembly.
- Penetrating oil (e.g., WD‑40 or similar)
- Description: Lubricant to free rusted nuts and bolts.
- How to use: Spray on seized fasteners and allow a few minutes to penetrate before attempting removal.
- Torque wrench (recommended but optional)
- Description: Tool that applies a controlled torque to fasteners.
- Why/How to use: Ensures bolts are tightened but not over-tightened; if unavailable, tighten snugly without excessive force; use torque wrench if specified torques are known.
- Wire or zip ties and silicone sealant (optional)
- Description: For temporary securing of hoses and small sealing needs.
- How to use: Use zip ties to secure hoses if clamps are temporarily missing; silicone can help seal minor leaks at hose joints (not a substitute for proper parts).

- Extra tools you might need and why
- Thread chaser or tap/die set
- Why: If tank studs or radiator mounting threads are corroded/damaged, you may need to clean or re-cut threads before installing replacement studs or bolts.
- Replacement studs or bolts
- Why: Old studs can be corroded, shear off, or have stripped threads and should be replaced to ensure secure mounting.
- Radiator pressure tester (optional)
- Why: Useful to check whether the system holds pressure after reassembly, ensuring there are no leaks; optional for a beginner but useful if leaks persist.

- Step-by-step process (bulleted)
- Prepare: Cool engine, set pan under tractor, have replacement parts and tools laid out.
- Drain enough coolant so the header tank and hoses are below the level to avoid a large spill: open lower radiator drain or carefully loosen a lower hose to let fluid into pan.
- Inspect visually: Note hose routes, clamp positions, and mounting method of header tank; take a photo if helpful to remember orientation.
- Remove hoses from the tank:
- Loosen hose clamps using screwdriver or pliers.
- Twist the hose gently while pulling to break the seal; use pliers to grip if stiff. Do not pry on radiator seams.
- Remove mounting fasteners:
- Use appropriate wrench or socket to remove bolts or nuts holding tank bracket.
- Apply penetrating oil first if rusted; let it soak, then work back and forth to free.
- Remove the tank:
- Lift out carefully; have pan below to catch residual coolant.
- Inspect mating surfaces and radiator top for corrosion or damaged studs.
- Inspect and decide repair vs replacement:
- If the tank has visible cracks, perforation, large rust-through, or threads are damaged, replace it.
- If only surface rust, you may clean, paint with coolant‑safe paint, and fit new hoses and clamps; small pinholes can sometimes be temporarily sealed with epoxy or radiator-safe sealants, but permanent replacement is preferred.
- Prepare replacement tank and parts:
- Clean radiator flange and hose fittings, remove old gasket material.
- Fit new hoses cut to correct length; slide clamps onto hoses before seating on fittings.
- Install replacement tank:
- Position tank and secure mounting bolts/nuts; tighten snugly but do not overtighten plastic or thin metal fittings.
- Reconnect hoses and tighten clamps so they compress the hose evenly; avoid crushing the hose.
- Refill coolant:
- Refill with the correct coolant/water mixture (commonly 50:50 antifreeze/water or as specified); use funnel to avoid spills.
- Fill slowly to reduce air pockets.
- Bleed air and check:
- Run the engine gently to operating temperature with the cap off (if safe and recommended for this tractor) to let air escape into the header tank; top up as needed.
- Replace cap, check for leaks at hoses, clamps, and tank mounting.
- Final check:
- After cool down, recheck coolant level and tightness of clamps/bolts.
- Dispose or recycle old coolant properly.

- How to use common tools safely (quick practical tips)
- Wrenches and sockets: Use correct size; pull on wrench rather than push to avoid slips; keep hands clear of pinch points.
- Screwdrivers: Use the right tip and size; holding the screw head and turning with force risks the driver slipping — brace firmly.
- Pliers: Use to grip, not to turn large nuts; avoid using pliers on hex bolts where wrench/socket fits.
- Ratchet/socket: Make sure socket fully engages the nut; use extension bars for awkward reaches.
- Hose removal: If hoses are stuck, cut them lengthwise to remove if you are replacing them; otherwise spray water or penetrating oil and twist before pulling.
- Cleaning surfaces: Use wire brush and rag, but avoid punching holes or grinding away sealing faces.

- Common problems and solutions
- Stuck or corroded hose fittings: Cut old hose off or use penetrating oil and gentle twisting; replace hoses.
- Stripped mounting threads: Use a replacement stud/bolt or chase threads; if radiator flange is damaged, professional repair or replacement may be required.
- Persistent leak after installation: Check clamp seating, hose condition, and cap seal; use new clamp/hose or replace cap.
- Air trapped in system: Proper bleeding (run engine with cap off until level stabilizes) usually clears air; if not, inspect for leaks that draw air in.

- Quick part reference for TE‑20 header tank replacement
- Header/header tank assembly (original or aftermarket reproduction) — replace if cracked or corroded.
- Radiator cap (correct pressure/fit for TE‑20) — replace if not sealing.
- coolant hoses (engine to tank and tank to radiator) — replace if aged.
- Hose clamps (worm-drive or spring clamps) — replace rusted or weak clamps.
- Mounting bolts/studs and nuts — replace if corroded or threads damaged.

- Disposal and cleanup
- Collect used coolant in a sealed container and recycle or dispose at an appropriate facility.
- Clean tools and work area; wipe up spills with absorbent material and wash hands.

- Final verification
- After driving briefly, recheck coolant level, cap tightness, and for leaks. Top up as necessary and recheck after a few hours of use.

- Minimal supplies summary to buy if you only have basic tools
- Replacement header tank (or repair kit), new hoses sized to fit, several hose clamps, radiator cap (if uncertain), coolant, basic socket/wrench set, flat and Phillips screwdrivers, pliers, hose cutter or sharp knife, drain pan, rags.

- Important note
- If you encounter badly corroded mounting points, welded-on tanks, or damage beyond simple hose/clamp repairs, consider professional radiator/tractor workshop help for safe repair.
rteeqp73

1950s Massey Ferguson te20 running and driving round stourbridge ring road 2021!

How to Replace a Ferguson TE20 PTO Seal and Bearing In this video I run through replacing the PTO seal and bearing on our 1948 TEA20 tractor.

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Summary first: the shift interlock on a Massey‑Ferguson TE‑20 is a mechanical safety/selection system inside the top of the gearbox/shift housing that prevents impossible or dangerous gear combinations and ensures only one selector rail is moved at a time. If it’s worn, broken, or out of adjustment you’ll get hard-to-shift gears, gears popping out, gear clash/grinding, or the lever jamming. Below is a complete beginner‑friendly diagnosis and repair walkthrough, with every component described, the theory of how it works, what can go wrong, and step‑by‑step repair instructions.

Safety first
- Work on level ground, switch off engine, remove key, disconnect battery (to avoid accidental starting).
- Cool engine and gearbox. Wear gloves, eye protection.
- Support tractor with blocks or stands if you need to crawl under. Drain gearbox oil into a catch pan and dispose/recycle properly.
- Keep fingers clear of moving parts when testing.

What the system is and how it works (theory, plain language)
- Gearbox basics (short): the TE‑20 uses sliding selector forks and rails to engage gears. Each gear is selected by sliding a fork/selector sleeve into mesh. If two forks move at once or a fork is pushed partially, gears can clash or break.
- Interlock purpose: act like a bouncer that only lets one selector rail move at a time and gives defined neutral positions/detents. It prevents simultaneous engagement of two gears and avoids accidental selection of reverse while moving forward or selecting two gears at once.
- Typical interlock components (analogy: a gatekeeper and locking bolts):
- Shift lever: the handle you move.
- Selector quadrant and top cover: houses the selector rails and interlock parts.
- Selector rails (rods): steel rods that slide fore/aft; each rail carries a selector fork.
- Selector forks: hooked pieces that move the gear collars/sleeves on the layshaft/mainshaft.
- Interlock pin/pawl or interlock cams: small steel pin or pawl(s) that engages slots on other rails to lock them when one rail is moved. Think of a keyed slot: when one rail moves, its notch blocks movement of the others.
- Detent balls and springs (or spring‑loaded plungers): give the lever a positive click into each gear position and help keep rails in place.
- Washers, bushes, circlips, cover gasket: hold assembly together and seal the housing.
- How it moves: when you move the shift lever, the top linkage rotates a selector collar that pushes a particular selector rail. The interlock pin or pawl rides in a groove or cross‑drilled hole that allows one rail to move while physically preventing others from sliding. When you return to neutral, detents hold them centered.

Symptoms of an interlock problem
- Lever jammed or hard to move into certain gears.
- Lever moves but gear does not engage.
- Can select two gears (rare but catastrophic): severe noise, metal fragments, abrupt lock‑up.
- Grinding/clashing when selecting gear.
- Gear pops out of gear under load.
- Abnormal play in the shift lever or inconsistent detents.

Tools and parts you’ll need
- Tools: metric/imperial socket set, open/box wrenches, screwdrivers, soft‑face hammer, punch, snap‑ring pliers (if applicable), pliers, torque wrench (recommended), drift, small magnet, parts tray, brake cleaner or solvent, rags, wire brush, hook pick.
- Consumables/parts: new interlock pin/pawl (or repair kit), detent ball(s) & springs, selector rail bushes, circlips, cover gasket or gasket maker, light assembly grease, gear oil to refill (use spec oil for TE‑20), replacement selector forks if worn, new screws/bolts if corroded.
- Replacement parts source: TE/TO/early MF parts suppliers, vintage tractor parts houses, or good-quality NOS/aftermarket pieces.

Step‑by‑step diagnosis and repair

1) Initial inspection / confirm problem
- With engine off, try shifting with clutch depressed and released, stationary and with brakes. Note which gears are affected and any specific point where lever jams or grinds. Listen/feel detents.
- Remove shift lever knob and dust cover to expose linkage. Look for bent links, missing cotter pins, or obvious broken parts.
- If problem is internal (lever free but no gear engagement, or grinding/dual selection), plan to open top cover.

2) Drain gearbox oil
- Place pan under gearbox and remove drain plug. Let oil drain fully. Keep pan for later reinstallation or disposal.

3) Remove shift lever and top cover
- Remove external linkages and the shift lever. Keep track of washers/spacers.
- Unbolt the top cover (selector cover) carefully. There may be a gasket; break it gently. Keep all bolts in a tray.
- Lift cover off slowly — inside will be selector rails, forks, springs, balls, and the interlock pin.

4) Visual inspection — identify each part (detailed)
- Selector rails: long rods running fore/aft. Each has a key or slot where the fork fits. Check for scoring, wear, straightness.
- Selector forks: slide on rails, have mating ears for gear collars. Check ears for wear (thinning, hooked teeth).
- Interlock pin/pawl: often a small transverse pin/pawl that fits into holes or grooves in one or more rails. It may be spring‑loaded or retained by a circlip. Check for broken or worn ends, missing springs.
- Detent balls & springs: small ball bearings sitting in cup holes with a spring beneath them; they fit into notches in selector rails to hold gear positions—check springs for weak/broken, balls for pitting.
- Bushes: sleeves where rails ride; check for ovaling or excessive clearance.
- Cover sealing surfaces/gasket.
- Any broken circlips, worn holes, metal shaving or scoring.

5) Clean parts
- Remove each part carefully one at a time; keep sequence for reassembly. Use a magnet and a tray for small parts.
- Clean with solvent/brake cleaner. Lay parts on a clean rag. Inspect each under good light.

6) Common faults and what to look for
- Worn interlock pin: ends rounded or pin loose — result: interlock doesn’t engage; rails can be moved together.
- Broken spring for interlock or detent: detents fail, rails drift and gear slips/pops.
- Worn detent notches or flattened balls: loss of positive gear positions.
- Worn selector forks or rails: poor engagement, gear popping.
- Worn bushes or oval rails: excessive play, inability to align collars for full mesh.
- Bent rail or misshapen holes: jamming.
- Debris/metal filings: indicates previous internal wear/damage — inspect dogs/collars for damage.

7) Replace worn/broken components
- Replace interlock pin/pawl and its spring(s) if worn or broken. If the pin is peened or broken, source correct reproduction part or have new pin made to same size/heat treatment.
- Replace detent springs and balls. Replace selector rail bushes if loose.
- If forks are worn, replace or rebush them — do NOT try to weld and file without correct heat treatment: you’ll risk breakage.
- If rails are bent or more than lightly scored, replace. Light scoring can be smoothed lightly with emery, but avoid removing significant material.

8) Reassembly details and adjustments (critical)
- Lightly lubricate rails and forks with assembly grease or light oil. Do not over‑oil the detent springs (some light oil is fine).
- Fit detent springs and balls into their holes with the correct orientation; the spring must seat under the ball to produce the click.
- Install interlock pin/pawl: ensure it locates into the intended grooves/holes in the rails and that any retaining clips or springs are correctly fitted.
- Confirm interlock action before closing cover: manually slide one rail and verify the pin blocks the others. The mechanism should allow only one rail to move at a time and should click into neutral and gear detents.
- Fit new gasket or sealant and replace cover bolts, tightening progressively in a crisscross pattern to seat cover evenly. Torque to a medium snug setting—don’t strip aluminum. If you have a torque spec, use it; otherwise tighten to snug and then a quarter turn.
- Reinstall shift lever, external linkage, and knob. Replace any seals or bushings at the lever base if fitted.

9) Refill gearbox and test
- Refill with correct spec gear oil for TE‑20 to the level required.
- With tractor on stands (wheels off ground) or safely on ground, start engine and test shifts with clutch depressed. Cycle through all gears slowly, listening for abnormal noises and checking for full engagement in each gear.
- Road test under light load, then medium load. If grinding persists, stop and recheck internal assembly.

Adjustment notes and fine tuning
- Detent spring preload: if it’s too light you’ll have loose detents; too stiff will make shifting hard. Replace springs rather than trying to over‑compress.
- Selector rail end‑float: excessive end‑float can permit forks to misalign. Replace worn bushes or add correct shims/washers as originally configured.
- Interlock clearance: the pin must sit fully engaged in its groove when in neutral; if too loose, replace; if too tight, check for burrs and polish lightly.

What can go wrong if done incorrectly (or if left unrepaired)
- Selecting two gears at once — catastrophic gear breakage, sheared dogs, broken shafts.
- Reassembly with wrong orientation of interlock pin allows free movement of multiple rails — immediate box damage when driving.
- Missing or weak detents causes popping out of gear and metal fatigue.
- Over‑tightening cover bolts can crack the housing.
- Wrong parts (improperly hardened pin or fork) will wear fast and fail.
- Reusing badly scored rails/forks leads to repeated failure.

Troubleshooting tips (quick checks)
- If lever moves but gears don’t: verify fork/rail engagement with cover off — see if rails are moving.
- If you hear internal clunk when shifting lightly: check detents and interlock wear.
- If parts look intact but problem persists: inspect the gear collars/dogs — they may be damaged and not locking fully.

Analogy wrap‑up
- Think of the interlock as a club bouncer and the selector rails as people trying to enter a room. The bouncer (interlock pin/pawl) only lets one person (rail) through at a time. If the bouncer is asleep (broken pin/spring) two people can get in and they’ll collide, causing a fight (gear clash/damage). The detents are the notches in the floor that make people stop at the right place — if those are worn, people will slip past and end up in the wrong place.

Final practical checklist before you go
- New interlock pin & spring fitted or confirmed good.
- New detent springs/balls and any worn bushes replaced.
- Selector rails/forks inspected and replaced if needed.
- Cover gasket replaced and bolts tightened evenly.
- Gearbox refilled to correct level with correct oil.
- Functional test through all gear positions, then road test.

This gives you a full beginner‑level guide: what each part is, how it works, what fails, and how to repair and test. Follow the steps carefully, keep parts organized, replace worn small parts rather than trying to jury‑rig, and you’ll restore reliable shifting.
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