★ EV / Hybrid Optimized · GB 12981 HZY6
Sinolook HZY6 / ISO 4925 Class 6 Brake Fluid
Premium-grade brake fluid engineered for electric vehicles, hybrids and modern brake-by-wire systems. ISO 4925 Class 6 combines DOT 4 LV low-viscosity benefits with DOT 5.1-class boiling points.
- Dry boiling point 267 °C · Wet boiling point 187 °C
- Certified to FMVSS 116, ISO 4925 Class 6, SAE J1703, GB HZY6
- Independently tested at ABIC Testing Laboratories (USA)
- Available bulk, drum, IBC and retail packaging — OEM & private label welcome
267 °C
Dry Boiling Point
187 °C
Wet Boiling Point
Class 6
ISO 4925 / GB HZY6
25 yrs
Manufacturing Experience
Product Overview
HZY6 / ISO 4925 Class 6 Brake Fluid
HZY6 (also designated ISO 4925 Class 6) is a premium-grade brake fluid specifically engineered for electric vehicles, hybrids and modern advanced driver assistance systems. It combines the high-temperature performance of DOT 5.1 with the low-viscosity benefits of DOT 4 LV — at 689 mm²/s at −40 °C, it is among the lowest-viscosity glycol-ether brake fluids in commercial production.
Manufactured at our IATF 16949:2016 certified plant in Nan'an, Fujian, Sinolook HZY6 brake fluid is verified by ABIC Testing Laboratories, Inc. to meet ISO 4925:2020 Class 6 and the Chinese national standard GB 12981 HZY6. Production batch typical values exceed the standard minimum on every parameter.
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Built for regenerative braking
EV and hybrid systems with regenerative-friction blending demand brake fluid that responds instantly to brake-by-wire commands. HZY6's 689 mm²/s viscosity at −40 °C delivers near-DOT 5.1 cold-flow performance.
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DOT 5.1-class boiling points
Typical dry ERBP of 267 °C and wet ERBP of 187 °C — 7 °C and 7 °C above the ISO Class 6 minimum, respectively. Comparable to standard DOT 5.1 performance.
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Glycol-ether compatibility
Fully miscible with all DOT 3, DOT 4, DOT 4 LV and DOT 5.1 brake fluids. Direct fill in any vehicle currently using a glycol-ether grade.
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Verified for modern ABS / ESC / EHB
Tested compatible with SBR and EPDM seals plus all common brake-system metals. Meets the demanding stability and oxidation requirements of long-life service intervals.
Technical Specifications
Sinolook HZY6 — typical production values
Enterprise typical values from current production batches. Every shipment is supplied with a Certificate of Analysis (COA) listing the batch-specific results. Independent ABIC test reports against FMVSS 116, ISO 4925, and SAE J1703 are available on request.
| Property | Test method | Typical value | ISO 4925 Class 6 min. |
|---|---|---|---|
| Appearance & Chemistry | |||
| Appearance | Visual | Clear, transparent | Free of suspended matter |
| pH value | ISO 4925 §6.3 | 7.91 | 7.0 – 11.5 |
| Boiling Point | |||
| Equilibrium reflux boiling point (Dry ERBP) | ISO 4925 §6.2 | 267 °C | ≥ 260 |
| Wet equilibrium reflux boiling point (Wet ERBP) | ISO 4925 §6.2.6 | 187 °C | ≥ 180 |
| Kinematic Viscosity | |||
| Viscosity at −40 °C | ISO 4925 §6.1 | 689 mm²/s | ≤ 750 |
| Viscosity at 100 °C | ISO 4925 §6.1 | 2.03 mm²/s | ≥ 1.5 |
| Corrosion (120 h @ 100 °C ± 2 °C, mg/cm²) | |||
| Tinned iron / Steel / Cast iron | ISO 4925 §6.5 | Within tolerance | ±0.2 |
| Aluminium | ISO 4925 §6.5 | Within tolerance | ±0.1 |
| Brass / Copper / Zinc | ISO 4925 §6.5 | Within tolerance | ±0.4 |
| Rubber Compatibility (120 °C, 70 h) | |||
| SBR — hardness change (IRHD) | ISO 4925 §6.10 | Within tolerance | ≤ −15 |
| SBR — volume increase | ISO 4925 §6.10 | Within tolerance | 1 – 16% |
| EPDM — hardness change (IRHD) | ISO 4925 §6.10 | Within tolerance | ≤ −15 |
| EPDM — volume increase | ISO 4925 §6.10 | Within tolerance | 0 – 10% |
Typical values from production batch. Highlighted figures indicate margin above the ISO 4925 Class 6 minimum requirement. Complete test reports — including fluidity, water tolerance, oxidation and stroking — issued per shipment by ABIC Testing Laboratories.
Recommended Applications
Where Sinolook HZY6 brake fluid is used
HZY6 is positioned for specific application profiles where its combination of boiling points, viscosity and chemistry delivers measurable advantages over standard grades.
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Battery electric vehicles (BEV)
EVs with regenerative braking and brake-by-wire systems where low viscosity enables fast pedal-response simulation.
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Plug-in hybrids (PHEV) & HEV
Hybrid vehicles where regenerative-friction blending requires high-frequency hydraulic valve actuation.
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Modern luxury & premium vehicles
High-spec vehicles with advanced electronic stability, autonomous emergency braking, and predictive collision avoidance systems.
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Heavy-duty commercial EVs
Electric buses, delivery trucks and last-mile commercial EVs requiring extended service intervals and high thermal resilience.
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High-performance road vehicles
Performance road cars where the combination of high boiling points and low viscosity provides both fade resistance and ABS responsiveness.
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Extreme-climate operation
Vehicles operating across wide ambient temperature ranges where both cold-flow viscosity and hot-weather wet ERBP matter.
Note: Always check the brake fluid reservoir cap on the master cylinder for the manufacturer's specification. Never use a fluid grade lower than specified. Glycol-ether brake fluids must never be mixed with DOT 5 silicone.
B2B Capability
Flexible packaging, OEM & global supply
Sinolook HZY6 is supplied in every commercial format — from 250 ml retail bottles for the aftermarket through to ISO tanks for high-volume lubricant blenders and OEM brake-system suppliers.
SERVICE 01
OEM & private label
Custom label design, custom bottle / drum colors, dedicated SKU codes. Artwork approval to first shipment in 25 – 35 days.
SERVICE 02
Retail & bulk packaging
250 ml · 500 ml · 1 L retail bottles · 5 L, 20 L, 200 L drums · 1,000 L IBC totes · flexitank · ISO tank.
SERVICE 03
Global logistics
Direct shipment ex Xiamen, Hong Kong or Singapore. FOB / CIF / DDP terms. UN 1992 / IMDG-compliant export packing.
SERVICE 04
Documentation per shipment
Technical Data Sheet (TDS), Safety Data Sheet (SDS), Certificate of Analysis (COA), AMECA notification, certificate of origin and CIQ documents.
Learn More
Brake fluid resources
In-depth guides on brake fluid chemistry, standards, and selection — written by our technical team.
Reference
Types of Brake Fluid Explained: DOT 3, 4, 4+, 5, 5.1, HZY6, Class 7
Every brake fluid grade compared — composition, boiling points, applications and selection chart.
Technical
Brake Fluid Boiling Point: Dry vs Wet, Why It Matters
How the ERBP test works, why fluid absorbs moisture, and how brake fade actually happens.
Standards
Brake Fluid Standards: FMVSS 116, ISO 4925, SAE J1703 & GB 12981
A B2B reference on the four major brake fluid standards and how they map to OEM specifications.
Compatibility
Can You Mix Brake Fluids? DOT 3, 4, 5.1 & DOT 5 Compatibility
A complete compatibility matrix — which combinations are safe, which will destroy your brake system.
EV / Hybrid
Brake Fluid for EVs & Hybrids: Why Low-Viscosity Matters
Regenerative braking, brake-by-wire, and why electrified vehicles need low-viscosity high-performance fluid.
Service Interval
How Often Should You Change Brake Fluid?
Manufacturer intervals, climate impact, and when symptom-based replacement makes sense.
FAQ
Frequently asked questions
What is HZY6 brake fluid?
HZY6 is the highest-class brake fluid designation under the Chinese national standard GB 12981, equivalent to ISO 4925:2020 Class 6. It combines DOT 4 LV-level low-temperature viscosity (≤750 mm²/s at −40 °C) with DOT 5.1-level boiling points (≥260 °C dry / ≥180 °C wet). Sinolook HZY6 brake fluid is specifically formulated for electric vehicles, hybrids and modern brake-by-wire systems.
How does HZY6 compare to DOT 5.1?
HZY6 (ISO Class 6) and DOT 5.1 (ISO Class 5-1) share similar dry and wet boiling points. The key advantage of HZY6 is its much lower low-temperature viscosity — Sinolook HZY6 measures 689 mm²/s at −40 °C compared to 800 mm²/s for our DOT 5.1. This makes HZY6 better suited for EV / hybrid applications where regenerative braking demands fast hydraulic response.
Is HZY6 compatible with DOT 4 brake fluid?
Yes. HZY6 is a glycol-ether based brake fluid, fully miscible with DOT 3, DOT 4, DOT 4 LV and DOT 5.1 from any manufacturer meeting FMVSS 116 or ISO 4925. It can be used as a direct upgrade in any system currently using a glycol-ether brake fluid. It must never be mixed with DOT 5 silicone brake fluid.
Which vehicles use HZY6 brake fluid?
HZY6 is increasingly specified by Chinese EV and hybrid OEMs, and by global manufacturers for vehicles equipped with advanced driver assistance systems (ADAS), autonomous emergency braking, and electro-hydraulic brake-by-wire architectures. Always check the brake fluid reservoir cap or owner's manual for the specified grade.
Is HZY6 the same as Class 7?
No — they are different grades. HZY6 corresponds to ISO 4925 Class 6 (dry ERBP ≥260 °C, viscosity ≤750 mm²/s at −40 °C). Class 7 is the highest ISO 4925 grade with even higher dry boiling points and lower viscosity (≥260 °C dry, ≤680 mm²/s at −40 °C in some specifications). See our Class 7 brake fluid for the higher tier.
Can I mix Sinolook HZY6 with other glycol-ether brake fluids?
Yes. Sinolook HZY6 is fully compatible with all other glycol-ether based brake fluids — DOT 3, DOT 4, DOT 4+, DOT 4 LV, DOT 5.1, HZY6 and Class 7 — from any manufacturer meeting FMVSS 116 or ISO 4925. It must never be mixed with DOT 5 silicone brake fluid, which is chemically incompatible and will damage seals.
What standards does Sinolook HZY6 meet?
Sinolook HZY6 brake fluid is certified to four major international standards:
• US FMVSS 116
• ISO 4925:2020 — Class 6
• SAE J1703
• GB 12981 HZY6 — China national standard
Independent test reports are issued by ABIC Testing Laboratories, Inc. in Fairfield, New Jersey, USA. Manufacturing operates under IATF 16949:2016 and ISO 9001:2015 quality systems.
• US FMVSS 116
• ISO 4925:2020 — Class 6
• SAE J1703
• GB 12981 HZY6 — China national standard
Independent test reports are issued by ABIC Testing Laboratories, Inc. in Fairfield, New Jersey, USA. Manufacturing operates under IATF 16949:2016 and ISO 9001:2015 quality systems.
What is the shelf life of unopened HZY6?
Sealed Sinolook HZY6 has a shelf life of 24 months from the production date when stored in original containers, away from direct sunlight, at 5 – 30 °C. Once opened, glycol-ether brake fluid begins absorbing atmospheric moisture (hygroscopy), which lowers its boiling point — opened containers should be used within 12 months.
What is the minimum order quantity for Sinolook HZY6?
Standard MOQ is 1 × 20'FCL, approximately 18–20 metric tons depending on packaging configuration. Smaller trial orders may be accepted for OEM and private-label customers. Bulk shipment in flexitank or ISO tank is available for orders 20 tons and above.
Does Sinolook offer OEM and private-label HZY6?
Yes. Sinolook offers full OEM and private-label service: custom label design, custom bottle and drum colors, custom packaging sizes from 250 ml to 200 L, and bulk supply. Lead time is typically 25 – 35 days from artwork approval. Contact sales@sinolook.com with your label artwork and packaging requirement.
Source HZY6 from a 25-year manufacturer
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