- Quick summary
- This guide covers inspecting, removing and replacing the gearbox/transfer-case breather hose(s) and associated clamps/connectors on Toyota H140F / H150F / H151F gearboxes. It assumes you are a complete beginner with basic hand tools. Follow safety steps exactly.

- Safety first
- Wear safety goggles and gloves to protect from dirt and oil.
- Work on a flat surface, engage parking brake, chock wheels.
- Use a jack and rated jack stands — never rely on the jack alone. If you must get under the vehicle, ensure it is properly supported.

- Tools you will need (detailed descriptions and how to use each)
- Floor jack and rated jack stands
- Description: Hydraulic jack to lift the vehicle and metal stands to support it safely.
- How to use: Position jack under specified lift point, raise vehicle just enough to place stands under manufacturer-recommended support points, lower the vehicle onto stands. Always test stability before going underneath.
- Why required: Provides safe access under the vehicle to reach gearbox/hoses.
- Wheel chocks
- Description: Rubber or plastic wedges placed behind wheels.
- How to use: Place behind wheels opposite the end you lift.
- Why required: Prevents vehicle roll while jacked.
- Flashlight or inspection lamp
- Description: Bright handheld light or shop lamp.
- How to use: Illuminate gearbox area to find hose routing, clamps, and connection points.
- Why required: Gearbox vents are often tucked away; good visibility is essential.
- Safety gloves and goggles
- Description: Mechanic gloves and eye protection.
- How to use: Wear while working.
- Why required: Protects hands and eyes from grime, hot parts, and metal edges.
- Socket set with ratchet and extensions (metric sizes)
- Description: Ratchet handle with interchangeable sockets (usually 8mm–19mm range).
- How to use: Select the correct socket, attach to ratchet, use extension to reach bolts. Turn clockwise to tighten, counterclockwise to loosen.
- Why required: Some retaining brackets or clamps may be fastened with bolts that need removal.
- Screwdrivers (flat-blade and Phillips)
- Description: Standard and Phillips screwdrivers, medium size.
- How to use: Use the appropriate tip to turn screws or pry spring clamps gently if applicable.
- Why required: Useful for undoing hose clamps, prying clips, and peeling boots off fittings.
- Pliers (needle-nose and slip-joint)
- Description: Needle-nose for getting into tight spaces, slip-joint for gripping.
- How to use: Squeeze to open/close retaining clips or pull off small hoses.
- Why required: Removing spring-type hose clamps and routing clips.
- Hose clamp pliers or strong locking pliers (vice-grips)
- Description: Pliers designed to compress spring clamps or hold standard clamps while you loosen screws.
- How to use: Compress spring clamps, then slide them away from the fitting; with vice-grips, clamp and hold while you work.
- Why required: Makes spring clamp removal much easier and safer.
- Utility knife or hose-cutting tool
- Description: Sharp blade or purpose hose cutter for clean cuts.
- How to use: Cut old hose lengthwise if it’s stuck, or cut new hose to length smoothly.
- Why required: Remove perished hose or cut new hose to fit; a clean cut prevents leaks or kinks.
- Small pick or flat-blade trim tool
- Description: Small metal or plastic pick for removing O-rings/retainers.
- How to use: Hook under clamps or remove rubber grommet carefully without tearing surrounding material.
- Why required: Useful to get into tight spaces to release clips and seals.
- Measuring tape or calipers
- Description: Small ruler or calipers to measure hose inner diameter and length.
- How to use: Measure diameter of the spigot on the gearbox/breather and length needed to route to the mounting point.
- Why required: Ensures you buy the correct ID hose and correct length.
- Replacement hose clamps (worm-gear or spring type) and zip ties
- Description: Stainless steel worm clamps or high-quality spring clamps; nylon zip ties for routing.
- How to use: Fit clamp over hose and tighten for worm clamps with screwdriver or secure spring clamps with pliers. Use zip ties to secure hose to nearby brackets.
- Why required: Old clamps often corrode or lose tension; new clamps ensure a secure, lasting fit.

- Parts you may need (what they are and why)
- Breather/vent hose (OEM or high-temp rubber/silicone vent hose)
- Description: Small-diameter hose that vents gearbox/transfer case to atmosphere or higher point.
- Why replace: Hoses age, harden, crack, split or get clogged. A failed breather can let water into gearbox or allow pressure to build, possibly forcing seals to leak.
- What to buy: OEM replacement vent hose for H140F/H150F/H151F if available, or universal automotive breather hose with the correct inner diameter and heat/alkali resistance (commonly ~4–8 mm ID — measure first). Silicone hose is more durable but stiffer; rubber breather hose is acceptable.
- Hose clamps (stainless steel worm clamps or OEM-style spring clamps)
- Description: Clamps secure the hose to the spigot or a vent fitting.
- Why replace: Corroded or loose clamps will not seal and are cheap insurance.
- What to buy: Small clamps sized for your hose OD; stainless steel for corrosion resistance.
- Rubber grommets or connector fittings (if found damaged)
- Description: Rubber grommet that seals the hose where it passes through bodywork or bracket.
- Why replace: A torn grommet can allow dirt/water in or let the hose chafe.
- Breather assembly (only if the gearbox breather itself is broken)
- Description: The plastic or metal vent fitting that connects to the gearbox.
- Why replace: If the fitting is cracked, bent or clogged, the hose won't seal or vent properly.

- How to identify the breather hose(s) and when replacement is required
- Signs to replace
- Hose is cracked, split, brittle or soft and collapsing.
- Hose has oil inside (indicates seal leak higher up) or is clogged.
- Hose clamp is corroded, broken, or missing.
- Hose is routed into a place where it can suck up water (poor routing) or is rubbing on a sharp edge.
- Where to look
- Trace from the gearbox/transfer case top or side to a hose that typically rises up toward the engine bay or firewall. On many H-series boxes it is a short rubber tube connected to a plastic nipple/vent. It may run to a higher mounting point or just be a short capped vent.

- Step-by-step procedure (concise, safe, in-bullet form)
- Prepare the vehicle: park on level ground, chock wheels, engage parking brake.
- Raise and support vehicle if needed for access: use floor jack to lift at recommended point, place jack stands under secure frame or lift points, lower vehicle onto stands and verify stability.
- Locate the breather vent on the gearbox/transfer case using flashlight: observe hose routing and how it’s attached (clamp, push-on, grommet).
- Inspect visually and by touch: check hose for cracks, softness or oil; wiggle clamp to check security.
- Remove old hose/clamps:
- If spring clamps: compress with pliers and slide clamp back along hose, then pull hose off the nipple. If stuck, twist gently while pulling.
- If worm-gear clamps: loosen the screw with a screwdriver or socket and slide clamp back.
- If the hose is stubborn, cut it lengthwise with a utility knife and peel it off carefully.
- If a grommet or fitting is present, use a pick to ease it out while supporting the gearbox fitting to avoid damage.
- Clean the fitting and surrounding area with a rag: remove grime so new hose seals correctly.
- Measure for replacement hose: measure the spigot diameter and needed length to match routing; add a small allowance for movement.
- Fit new hose:
- Slide the selected new hose onto the vent nipple. If using silicone, apply a little clean engine oil or soapy water to ease fit if very tight.
- Position clamp near the base of the hose (not over the edge of the nipple) and tighten worm-gear clamps until snug — do not over-torque (tighten until it’s secure but not crushing the hose). For spring clamps, compress and locate over the nipple shoulder.
- Route the hose so it goes upward or to a safe higher point, secured with zip ties or re-used routing clips; avoid sharp edges, hot parts and moving components.
- Reinstall any grommets or brackets removed; ensure the hose end is free from being immersed in water or a low point where water could collect.
- Final checks:
- Ensure the hose is secure and not kinked.
- Start engine and, with safe clearance, observe area for leaks or humm noise; static breather normally has no fluid flow — but if oil appears it may indicate internal seal or overpressure problems.
- Lower the vehicle only after removing jack stands and checking that nothing was left loose.

- When replacing the hose is not enough — other parts to consider
- If oil is present inside the breather hose or the gearbox is leaking:
- Possible seal failure inside gearbox/transfer case or overfilled gearbox — inspect fluid level and seals.
- Required parts may include gearbox output shaft seals, input shaft seals, or the entire breather assembly if contaminated/clogged.
- If you see oil spitting from the breather intermittently while running/after driving, have the gearbox checked by a competent mechanic — internal problems may require professional repair.
- If the vent fitting on the gearbox is cracked:
- Replace the breather/vent fitting or the gearbox breather assembly (OEM part recommended). If the fitting is integral and gearbox case damaged, professional repair is required.

- Tips and common beginner mistakes
- Don’t overtighten clamps — overtightening can cut the hose or damage the nipple.
- Route the hose upward if possible — keeps water from pooling into the vent.
- Always replace old clamps when they are corroded — they are cheap insurance.
- If unsure of hose diameter, bring the old hose or measure the spigot and take that to the parts store.
- If you find oil inside the breather hose, stop and inspect further — replacing hose alone won’t fix an internal seal failure.

- Estimated parts cost (approximate)
- Replacement breather hose: small (a few feet) – depending on material.
- Hose clamps (pack): –.
- Rubber grommet or OEM vent fitting: – depending on source.
- If internal seals or gearbox work needed: parts and labor vary widely; professional diagnosis required.

- Closing
- Replacing a gearbox breather hose on H140F / H150F / H151F is a straightforward beginner task if the problem is simply a cracked hose or bad clamp. Use the listed tools, follow safety steps, and replace clamps and grommets as needed. If you find oil inside the hose or see active leaks from the gearbox, stop and get a professional inspection — that indicates more than just a hose issue.
rteeqp73

How to Change Manual Transmission Oil – Toyota Landcruiser 80 Series In this video we show how to change the manual transmission oil of an 80 Series Landcruiser. The video applies to all 80 series ...

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Short, ordered procedure (with theory) for the clutch slave-cylinder piston inside Toyota H140F / H150F / H151F gearboxes. I assume you mean the hydraulic clutch slave piston that sits in the gearbox bellhousing (common failure on these gearboxes). No needless chat — steps and theory only.

Theory — what the piston does and how it fails
- Function: the clutch master pushes hydraulic fluid into the slave cylinder bore. The piston in the bore translates fluid pressure into axial movement of the clutch release bearing/rod → disengages the clutch.
- Seals: piston uses at least one rubber seal/boot to keep fluid pressure and keep dirt out. The bore surface must be smooth and corrosion-free.
- Failure modes:
- Seal wear/cutting → internal leak (loss of pressure) → soft pedal, incomplete disengagement.
- Pitting/corrosion in bore or on piston → seal damage, external leak.
- Contamination/abrasion → seal scoring.
- Bent piston or damaged return spring/boot → sticking or slow return.
- Observable symptoms linked to failure: low or leaking hydraulic fluid, spongy/soft clutch pedal, clutch drag/grinding on shifts, visible fluid around bellhousing.

Ordered repair procedure (theory linked to each action)
1) Prepare safely
- Park, chock wheels, disconnect battery, lift vehicle and support on stands. Drain clutch hydraulic circuit or isolate fluid to avoid contamination.
- Theory: clean working environment prevents contamination of new seals and fluid which will cause immediate failure.

2) Remove gearbox (if required by model)
- On most H140/150/151 you must remove gearbox or at least separate it from engine to access internal slave piston. Remove driveline, linkages, starter, bellhousing bolts. Support gearbox and lower/transaxle safely.
- Theory: slave piston is inside bellhousing; removal gives access for correct cleaning/inspection and replacement without damaging mating surfaces.

3) Open bellhousing / remove clutch components as needed
- Remove clutch release bearing/rod to expose slave-cylinder bore and piston area. Clean external area before opening to prevent contamination ingress.
- Theory: removing adjacent components prevents recontamination and allows measurement/inspection.

4) Extract piston assembly
- Depending on design: either pull piston and spring/rod assembly out by hand or through small access hole; some pistons are retained by circlips/retainers — remove them first. Note orientation and component order.
- Theory: remove old components to inspect for wear and to fit new seals oriented correctly (lip direction matters for pressure/return).

5) Inspect bore and piston
- Visually and with light/feel examine bore for pitting, scoring, corrosion. Measure bore for out-of-round if precision tools available. Inspect piston for scoring, chamfer wear, corrosion.
- Theory: seals require a smooth bore and undamaged piston. Small scratches can be polished; pitting or deep corrosion means replacement or sleeving of cylinder body — otherwise new seals will leak quickly.

6) Clean thoroughly
- Use brake/parts cleaner and lint-free cloths to remove old fluid and debris. Do not use petroleum-based cleaners that swell seals. Blow out with low-pressure compressed air if available (keep fluid passages clear).
- Theory: any debris will be trapped by new seal lips and cut them during first actuation.

7) Replace piston seals/boot (or entire piston) and any retaining hardware
- Fit OEM-quality seal kit (piston seal, dust boot, spring, circlip as applicable). Lubricate seals with clean recommended hydraulic fluid (DOT3/4/5.1 per vehicle spec) while installing. Install piston in correct orientation and secure retaining ring.
- Theory: new seals restore the hydraulic pressure containment and dust boot prevents contamination; lubrication prevents initial seal damage and provides correct friction.

8) Address bore damage if present
- If bore lightly scored, polish with very fine crocus cloth and re-clean. If bore is pitted/corroded beyond light polish, replace the entire slave cylinder housing or sleeve/repair, or replace gearbox assembly. Do not fit new seals to badly damaged bores.
- Theory: pressure integrity requires a defect-free sealing surface. A patched seal will fail quickly if sealing surface is poor.

9) Reassemble clutch release components and gearbox
- Reinstall piston/rod/release bearing, ensuring correct preload/orientation. Refit bellhousing and gearbox; torque bolts to Toyota specs.
- Theory: correct reassembly ensures axial travel and geometry are preserved so piston movement translates properly to clutch fork/release bearing.

10) Refill and bleed hydraulic system
- Refill master cylinder to correct fluid spec. Bleed system until there is firm pedal and no air. Bench-bleed any remote components if necessary.
- Theory: air is compressible and will cause spongy pedal despite a perfect piston/seal. Proper bleeding restores incompressible fluid column so piston movement equals pedal input.

11) Functional check and leak test
- With gearbox reinstalled, run engine, operate clutch to check disengagement/engagement under load and inspect for leaks around bellhousing/pipe fittings.
- Theory: verifies hydraulic integrity and that piston travel and return are correct.

How this repair fixes specific faults (direct mapping)
- Symptom: soft/spongy pedal → Cause: internal seal leak or air in system → Fix: new seals + correct bleed remove internal leaks and air, restoring pressure transmission.
- Symptom: clutch dragging/grinding on shifts → Cause: piston not fully extending or return sticking → Fix: new piston/seal and cleaned bore allow full movement; spring/boot restores return.
- Symptom: external leak at bellhousing → Cause: damaged seal/boot or damaged bore → Fix: replacing seals (or cylinder) removes leak path; repairing bore prevents resealing failure.
- Symptom: rapid re-failure after seal change → Cause: bore/piston damage or contamination → Fix: replacing whole cylinder or repairing bore removes mechanical cause rather than just replacing soft seal.

Key cautions (brief)
- Use correct hydraulic fluid; incompatible fluid will ruin seals.
- If bore is damaged, replacing seals is only a temporary fix; replace the cylinder/gearbox.
- Keep everything scrupulously clean.
- Use OEM or quality seal kits and torque to spec.

Done.
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