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Views: 0 Author: Site Editor Publish Time: 11-11-2025 Origin: Site
The engine mount connects the engine/transmission to the body, reducing NVH and providing location/support under acceleration, braking, and road inputs.
· NVH control: Rubber/hydraulic composite uses working & compensation chambers connected by an orifice to create low‑frequency damping peaks; mid‑high frequencies rely on rubber dynamic stiffness & hysteresis.
· Durability: Appropriate hardness/formulation/orifice damping reduces high‑cycle fatigue & thermal aging; robust rubber‑to‑metal bonding prevents peel and cavity knock.
· Handling vs. comfort: The ratio of lateral/longitudinal stiffness and damping defines launch shake, idle resonance, pitch under hard accel, and shift feel.
Part 12305-28150 is commonly a hydraulic engine mount (variants exist by model year/platform—verify by physical part & service manual).
· Rubber body: NR/NBR/HNBR/EPDM; hardness, section, and cavity design set static/dynamic stiffness and media resistance.
· Hydraulic chamber: working and compensation chambers connected by an orifice; fluid oscillation under low‑frequency, large displacement creates viscous damping to suppress resonance and shake.
· Metal base/upper cap: stamped/cast steel or aluminum; blasted + primed in critical areas for retention and corrosion resistance.
· Limiters & locators: limit ribs/shoulders prevent over‑travel in extreme impacts.
· Vulcanized bond: primer/adhesive/topcoat tri‑layer; single‑cure molding. Peel strength meets/exceeds ASTM D429; resists oil, hot‑water shock, thermal cycling.
Material | Typical Hardness (Shore A) | Continuous Temp | Oil/Fuel Resistance | NVH Behavior | Typical Use |
NR (Natural Rubber) | 45–60 | −40 to +90 °C | ★ | Supple, low noise | Urban comfort / idle isolation |
NBR (Nitrile) | 55–70 | −30 to +110 °C | ★★★ | Slightly firmer | Light/medium oil & hot zones |
HNBR (Hydrogenated NBR) | 55–75 | −40 to +150 °C | ★★★★ | Stable | High temp + oil contamination |
EPDM | 50–65 | −40 to +125 °C | ★ | Water/heat resistant | Humid/hot with low oil |
Recommendations: Comfort—NR/HNBR 50–60A + medium damping. Standard—NBR/HNBR 60–65A + balanced orifice. Heavy‑duty/towing—HNBR 65–70A + high damping + reinforced limiter.
Standard: 12305-28150
Common mistypes/SEO variants: 1230528150 (hyphen removed); 12305 28150 (spaces); 12305-2815O (letter O vs digit 0); 12305-28150A/B (suffix—verify dimensions).
Fitment: Toyota RAV4 (select model years/sub‑platforms) at engine‑side or body‑side mount positions. Verify by VIN, service manual, and on‑vehicle measurement.
Template parameters for quick checks—final spec must follow drawing & on‑vehicle measurement (CMM report available).
Variant | Center Height H | Base Bolt PCD | Body-Side Hole d₁ | Engine-Side Through-Bolt d₂ | Thread Spec | Ref. Tolerance |
A | 70.0 mm (2.756 in) | 85.0 mm (3.346 in) | 10.5 mm (0.413 in) | 12.0 mm (0.472 in) | M10×1.25 | Dim ±0.20 mm; Hole H13 |
B | 72.0 mm (2.835 in) | 90.0 mm (3.543 in) | 10.5 mm (0.413 in) | 12.0 mm (0.472 in) | M10×1.25 | Same as above |
If PCD mismatch exists with body holes, order micro‑adjusted hole‑spacing or request matched tolerance bands. If idle shake is excessive, consider lower hardness + higher‑damping orifice where strength allows.
1. Confirm install position & variant: measure H/PCD/hole diameters; confirm hydraulic type.
2. Road condition: Urban/highway → Comfort (50–60A + medium damping). Rough/unpaved → Heavy‑duty (65–70A + high damping + thicker limiter).
3. Load/use: Long full‑load/towing/aggressive launches → +5A hardness and limiter reinforcement.
4. Temperature & oil: Hot bay or oil seepage → NBR/HNBR; humid/hot water → consider EPDM.
5. NVH target: Idle isolation → softer (50–58A) + higher damping; shift‑shock control → 60–65A + balanced chamber.
6. Lead time & MOQ: Samples 50–100 sets; 7–15 days; customization 20–30 days (excluding new tooling).
Tools: Engine support/hoist, torque wrench, sockets, marker, cleaner, thread locker (per manual), oil‑resistant assembly lube (metal interfaces only).
7. Disconnect battery as required; support engine; mark original position.
8. Loosen engine‑side and body‑side fasteners; remove old mount; clean mating surfaces.
9. Seat new mount via locating pins/steps; avoid twisting rubber.
10. Hand‑tighten to seat → lower to design ride height → final torque per manual.
11. Road‑test cold & hot; check vibration/noise.
Reference torque (planning): Body‑side 60–85 N·m; Engine‑side 55–75 N·m. Re‑torque after 800–1,200 km; recheck after severe impacts.
Common mistakes:
· Torquing with wheels hanging → rubber pre‑twist & early crack → torque at ride height.
· Lube on rubber → bondline slip/migration → apply only to metal interfaces.
· No powertrain support during install → overstretch/twist → always support/level.
· Wrong torque → noise or thread damage → use calibrated torque wrench and record values.
Symptom | Possible Cause | Solution |
Idle shake/resonance | Insufficient damping/hardness too high/installation stress | Comfort orifice + softer rubber; re‑install; final torque at ride height |
Thump on launch/shift | Debonding/soft limiter/low torque | Replace; reinforced limiter; torque to spec |
Cold‑weather squeal | Poor low‑temp loss/hardness too high | NR/HNBR 50–58A low‑temp compound |
Large pitch under hard accel | Insufficient stiffness/low damping | 60–65A + medium‑high damping or heavy‑duty |
Early cracking/swelling | High temp + oil/chemicals | HNBR/NBR; fix leaks |
Fluid seepage | Hydraulic chamber weld/seal failure | Replace; inspect surfaces & torque |
· Systems & certifications: ISO 9001 / IATF 16949 / ISO 14001 / ISO 45001 / GJB 9001C / AS9100D / AEO; PPAP/IMDS/control plan available.
· Lab & validation: ASTM D2240 hardness; ISO 37 tensile; ISO 815 compression set; ASTM D429 rubber‑metal peel; salt spray/ozone/heat aging; hydraulic chamber leak & fatigue (>10⁶ cycles); NVH dynamic‑stiffness & frequency response.
· Traceability: unique piece barcode + batch ID; full trace of compound/chamber parts/key processes.
· Differentiators: dual‑channel customization (hardness + orifice), OD/hole‑spacing micro‑tuning, limiter reinforcement, high‑temp oil‑resistant compounds; optional CMM dimensions & peel/hardness/NVH reports.
· Case: LATAM distributor used HNBR 65–70A high‑damping mounts with complaint reduction; EU workshop used 50–58A comfort version improving idle isolation (client‑authorized aggregated data).
· Q: Is 12305-28150 the same as 1230528150?
A: Yes—the hyphen‑less variant. Verify position & dimensions.
· Q: How to balance comfort vs. durability?
A: Urban/idle isolation → 50–60A comfort orifice; heavy load/rough roads → 65–70A heavy‑duty orifice.
· Q: Are hydraulic mounts always better?
A: They isolate low frequencies better but are more sensitive to sealing & installation; choose HNBR in oily environments.
· Q: What if I hear a thump on launch?
A: Check for debonding, torque, and limiter; consider reinforced limiter or higher damping.
· Q: How to handle cold‑weather squeal?
A: Use low‑temp NR/HNBR (50–58A) and ensure final torque at ride height.
· Q: Micro‑adjust hole spacing or center height?
A: Yes—micro‑oversize +0.05 / +0.10 mm and tolerance matching are available.
· Q: PPAP & test reports available?
A: Yes—PPAP/IMDS/CMM/peel/hardness/NVH on request.
· Q: Lead time & MOQ?
A: Samples 50–100 sets; 7–15 days; customization 20–30 days.
