★ Glycol-Ether · NOT Silicone
Sinolook DOT 5.1 Brake Fluid
High-performance synthetic glycol-ether hydraulic fluid — the highest-spec brake fluid in the DOT family that remains compatible with DOT 3 and DOT 4.
- Dry boiling point 267 °C · Wet boiling point 185 °C
- Certified to FMVSS 116, ISO 4925 Class 5-1, SAE J1703, GB HZY5
- Glycol-ether based — fully compatible with DOT 3 and DOT 4
- Engineered for sportbikes, performance vehicles & commercial fleets
267 °C
Dry Boiling Point
185 °C
Wet Boiling Point
Class 5-1
ISO 4925 Grade
25 yrs
Manufacturing Experience
Product Overview
The highest glycol-ether brake fluid grade
DOT 5.1 brake fluid combines the highest boiling points permitted in the DOT 3 / 4 / 5.1 glycol-ether family with full backward compatibility. It is the preferred choice for sportbikes, performance road vehicles, demanding commercial fleets, and aftermarket upgrades of vehicles originally specified for DOT 3 or DOT 4.
Manufactured at our IATF 16949:2016 certified plant in Nan'an, Fujian since 2000, Sinolook DOT 5.1 brake fluid is a synthetic glycol-ether blend independently verified by ABIC Testing Laboratories, Inc. in the United States. It meets all four major international brake fluid standards: FMVSS 116, ISO 4925 Class 5-1, SAE J1703, and GB 12981 HZY5.
!
DOT 5.1 is NOT the same as DOT 5. Despite the similar names, these two grades are chemically opposite. DOT 5.1 is glycol-ether based and fully compatible with DOT 3 and DOT 4. DOT 5 is silicone based and chemically incompatible — mixing the two will damage seals and cause brake system failure. Sinolook manufactures glycol-ether DOT 5.1 only. If your application requires silicone DOT 5 (primarily older Harley-Davidson motorcycles and certain military vehicles), please contact our sales team.
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Class-leading boiling points
Typical dry ERBP of 267 °C and wet ERBP of 185 °C — the highest values in the glycol-ether family. Strong resistance to brake fade under repeated heavy braking.
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Backward compatible
Fully miscible with DOT 3, DOT 4, DOT 4+ and DOT 4 LV. Upgrading existing systems from a lower-spec glycol-ether fluid to DOT 5.1 requires no system flush.
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Improved cold-temperature flow
Kinematic viscosity of 813 mm²/s at −40 °C — significantly lower than DOT 4 (1,300 mm²/s) — for faster ABS valve response in cold climates.
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Verified seal & metal compatibility
Tested compatible with SBR and EPDM seals plus all common brake-system metals — tinned iron, steel, cast iron, aluminium, brass, copper and zinc.
Disambiguation
DOT 5.1 vs DOT 5 — side by side
The numerical similarity between DOT 5 and DOT 5.1 causes more confusion than any other brake fluid naming convention. Here is the practical difference.
| Property | DOT 5.1 (Sinolook) | DOT 5 (Silicone) |
|---|---|---|
| Chemistry | Glycol-ether (polyalkylene glycol ether borate ester) | Silicone (polydimethylsiloxane) |
| Hygroscopic (absorbs water) | Yes — like all glycol-ether fluids | No — water separates and pools |
| Mixable with DOT 3 / DOT 4 | Yes — fully compatible | No — chemically incompatible |
| Suitable for ABS systems | Yes — standard for modern ABS / ESP | Generally not recommended for ABS |
| Damages paint on contact | Yes — wash off immediately | No — paint-safe |
| Typical use case | Performance road, sportbikes, commercial fleet | Older Harley-Davidson, military, show vehicles |
| Sinolook manufactures | ✓ Yes — this product | No (available on consultation) |
Reference: FMVSS 116 §S5 specifies separate test methods for petroleum-based (DOT 5) and non-petroleum-based (DOT 3, 4, 5.1) brake fluids. Read the full DOT 5 vs DOT 5.1 chemistry guide.
Technical Specifications
Sinolook DOT 5.1 — 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 5-1 min. |
|---|---|---|---|
| Appearance & Chemistry | |||
| Appearance | Visual | Clear, transparent | Free of suspended matter |
| pH value | ISO 4925 §6.3 | 8.52 | 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 | 185 °C | ≥ 180 |
| Kinematic Viscosity | |||
| Viscosity at −40 °C | ISO 4925 §6.1 | 813 mm²/s | ≤ 900 |
| Viscosity at 100 °C | ISO 4925 §6.1 | 2.26 mm²/s | ≥ 1.5 |
| Corrosion (120 h @ 100 °C ± 2 °C, mg/cm²) | |||
| Tinned iron / Steel / Cast iron | ISO 4925 §6.5 | ±0.008 max | ±0.2 |
| Aluminium | ISO 4925 §6.5 | −0.002 | ±0.1 |
| Brass / Copper | ISO 4925 §6.5 | +0.061 / +0.045 | ±0.4 |
| Zinc | ISO 4925 §6.5 | −0.023 | ±0.4 |
| Rubber Compatibility (120 °C, 70 h) | |||
| SBR — hardness change (IRHD) | ISO 4925 §6.10 | −5 | ≤ −15 |
| SBR — volume increase | ISO 4925 §6.10 | 6.32% | 1 – 16% |
| EPDM — hardness change (IRHD) | ISO 4925 §6.10 | −3.0 | ≤ −15 |
| EPDM — volume increase | ISO 4925 §6.10 | 3.47% | 0 – 10% |
Typical values from production batch (representative QC sample). Highlighted figures indicate margin above the ISO 4925 Class 5-1 minimum requirement. Complete test reports — including fluidity, water tolerance, oxidation and stroking — issued per shipment by ABIC Testing Laboratories.
Recommended Applications
Where Sinolook DOT 5.1 brake fluid is used
DOT 5.1 is the upgrade path of choice for any application that pushes a brake system harder than the original DOT 3 or DOT 4 specification was designed for — without leaving the safety of the glycol-ether family.
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Sportbikes & performance motorcycles
High-performance street and track motorcycles benefit from DOT 5.1's higher boiling points during aggressive braking. The most popular upgrade fluid for sportbike riders.
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Performance road cars
Modified or high-performance road cars facing heavier thermal duty — track-day enthusiast vehicles, sport sedans, and tuned applications.
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Heavy-duty commercial fleets
City bus fleets, delivery trucks and other commercial vehicles operating in mountainous routes or stop-and-go duty cycles where DOT 4 would degrade faster.
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EVs & hybrids (selected models)
Many electric and hybrid vehicles specify DOT 5.1 for its lower viscosity and faster regen-braking response. Check the reservoir cap or owner's manual.
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Aftermarket upgrade path
A direct fill-and-forget upgrade for vehicles originally specified for DOT 3 or DOT 4 where the owner wants higher thermal margin without a system flush.
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Mountain & tropical climates
Regions where extended downhill braking and high ambient humidity put extra thermal and hygroscopic stress on the brake fluid.
Note: Always check the brake fluid reservoir cap on the master cylinder for the manufacturer's specification. DOT 5.1 can safely replace DOT 3 or DOT 4 — but never use it in systems originally specified for silicone DOT 5.
B2B Capability
Flexible packaging, OEM & global supply
Sinolook DOT 5.1 is supplied in every commercial format — from 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.
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Global logistics
Direct shipment ex Xiamen, Hong Kong or Singapore. FOB / CIF / DDP terms. UN 1992 / IMDG-compliant export packing.
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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.
Disambiguation
DOT 5 vs DOT 5.1 Brake Fluid: Silicone vs Glycol Explained
Why DOT 5 (silicone) and DOT 5.1 (glycol) are not interchangeable, and why they must never be mixed.
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.
Compatibility
Can You Mix Brake Fluids? DOT 3, 4, 5.1 & DOT 5 Compatibility
A complete compatibility matrix — which brake fluids can mix and which combinations will destroy your brake system.
Use Case
Motorcycle Brake Fluid Guide: DOT 4, DOT 5.1 & When DOT 5 Is OK
Why most modern motorcycles use DOT 4 or DOT 5.1, and which Harley-Davidson models specify DOT 5 silicone.
Performance
Racing Brake Fluid: High-Performance Options & Track-Day Picks
What makes a brake fluid "racing grade", target boiling points for track use, and how Class 7 compares.
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.
FAQ
Frequently asked questions
What is DOT 5.1 brake fluid?
DOT 5.1 is a high-performance glycol-ether based hydraulic brake fluid that meets FMVSS 116 and ISO 4925 Class 5-1 specifications. Despite the numerical similarity to DOT 5, it is chemically different — DOT 5.1 is glycol-ether based and fully compatible with DOT 3 and DOT 4, while DOT 5 is silicone-based and incompatible with all other grades. Sinolook DOT 5.1 has a dry boiling point of 267 °C and a wet boiling point of 185 °C.
Is DOT 5.1 the same as DOT 5?
No. DOT 5.1 and DOT 5 are chemically opposite despite the similar names:
• DOT 5.1 — glycol-ether based, hygroscopic, compatible with conventional rubber seals, fully miscible with DOT 3 and DOT 4
• DOT 5 — silicone based, hydrophobic, NOT compatible with ABS systems, must never be mixed with any glycol-ether brake fluid
Sinolook manufactures glycol-ether DOT 5.1 only. Read our full DOT 5 vs DOT 5.1 chemistry guide.
• DOT 5.1 — glycol-ether based, hygroscopic, compatible with conventional rubber seals, fully miscible with DOT 3 and DOT 4
• DOT 5 — silicone based, hydrophobic, NOT compatible with ABS systems, must never be mixed with any glycol-ether brake fluid
Sinolook manufactures glycol-ether DOT 5.1 only. Read our full DOT 5 vs DOT 5.1 chemistry guide.
Can I mix Sinolook DOT 5.1 with DOT 4 or DOT 3?
What standards does Sinolook DOT 5.1 meet?
Sinolook DOT 5.1 brake fluid is certified to:
• US FMVSS 116
• ISO 4925:2020 — Class 5-1
• SAE J1703
• GB 12981 HZY5 — 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 5-1
• SAE J1703
• GB 12981 HZY5 — 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.
Is DOT 5.1 suitable for motorcycles?
Yes. DOT 5.1 is widely used in sportbikes, performance motorcycles, and motorcycles with aggressive braking demands. Its higher dry and wet boiling points (267 °C / 185 °C) provide stronger resistance to brake fade during repeated heavy braking compared to DOT 3 or DOT 4. Always check the brake fluid reservoir cap for the manufacturer's specification — DOT 5.1 can replace DOT 3 or DOT 4 but not DOT 5 silicone. Read our full motorcycle brake fluid guide.
What is the shelf life of unopened DOT 5.1?
Sealed Sinolook DOT 5.1 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 DOT 5.1?
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 DOT 5.1?
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 DOT 5.1 from a 25-year manufacturer
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