50-68-7 Standard High-Pressure Seal 50687 TCV Oil Seal?

In heavy-duty hydraulics, the humble lip seal does the quiet, unglamorous work. The one I keep seeing on shop benches lately is the 50-68-7 Standard high pressure seal 50687 TCV oil seal. On paper it’s just 50×68×7 mm. In the field, it’s the difference between a travel motor that hums along and a teardown at month three.

Origin matters in sealing. This model comes out of the Development Zone, Julu County, Xingtai City, Hebei Province—a cluster that’s been quietly refining rubber-metal bonding tech for years. Many customers say the finish quality has stepped up lately; I’ve noticed that too.

What it is (and where it works)

The 50-68-7 Standard high pressure seal 50687 TCV oil seal is a TCV-profile rotary shaft lip seal for hydraulic pump, travel motor, rotary pump, and vertical shaft duty—typical earthmoving platforms: excavators, road rollers, scrapers, loaders, dumpers, mixer trucks. TCV generally means rubber-coated OD, metal case support, spring-loaded primary lip with a dust lip. In high-pressure builds, a backup ring or reinforced heel is used to resist extrusion—depends on your spec, so do ask.

Key specifications (typical)

Lab data I’ve seen: bench pressure hold at 1.5 MPa for 24 h at 80°C without visible leakage; dynamic run-up to 6 m/s on ISO 6194 rig; shaft finish around Ra 0.2–0.4 μm and hardness ≥55 HRC recommended. Your mileage, as ever, depends on housing tolerances and fluid chemistry.

How it’s made (quick process flow)

Compounding (ASTM D2000 targets) → metal case cleaning and phosphating → primer/adhesive (e.g., Chemlok) → compression/injection molding and vulcanization → post-cure (for FKM) → flash trimming, OD grinding → lip finishing and spring fit → 100% visual + sampling tests (DIN 3760 air leak, ISO 6194 run-out, pressure-burst bench). Service life in mixed-duty fleets is often 2,000–5,000 h; I’ve seen more with stable oil temps and clean breathers.

Applications and feedback

Use it in excavator travel pumps, loader hydrostatic drives, road roller vibratory pumps, and vertical mixer shafts. Field notes: “seal held through summer heat, less weeping at idle,” as one maintenance chief told me. Another shop noticed a small drop—about 18%—in top-up oil between PMs after switching to FKM in high ambient jobs.

Customization matters

• Elastomer: NBR for mineral oil, HNBR for bio/synthetic blends, FKM for heat and aggressive media.
• Pressure kit: anti-extrusion ring or fabric-reinforced heel for >1 MPa duty.
• Dust lip geometry for muddy worksites; spring material upgrade (SS304/316) for corrosion.
• Certification pack: CoC, material traceability, ISO 9001 QMS documents (on request).

Vendor snapshot (what buyers compare)

Mini case study

A quarry’s 22-ton excavator was chewing through travel motor seals every 4–5 months. Swap-in was a 50-68-7 Standard high pressure seal 50687 TCV oil seal in FKM with a reinforced heel and stainless spring. Result: 2,300 hours leak-free so far; motor temps peaked at 92°C on hot days, still within the seal’s comfort zone. They also tightened shaft runout to

Trend watch

Hydraulics are getting hotter and cleaner (better filtration, bio-oils). Seals need compatibility with HEES/HETG fluids and, to be honest, growing scrutiny on fluorinated elastomers. Some buyers now specify HNBR where they can. Still, for high-heat missions, FKM remains the workhorse.

Citations

1. ISO 6194: Rotary shaft lip-type seals — Dimensions, tolerances, and performance.
2. DIN 3760/3761: Rotary shaft lip seals — Types and requirements.
3. ASTM D2000: Standard Classification System for Rubber Products in Automotive Applications.
4. ISO 9001: Quality management systems — Requirements.