A boiling point that falls as the fluid takes on water

The best motorcycle brake fluid for 2026

Brake fluid is specified by a DOT number, and the number describes a set of published minimum properties rather than a brand or a quality tier. The two that matter are boiling points, and they are published as a pair for a reason. The dry boiling point is measured on fresh fluid. The wet boiling point is measured on fluid that has absorbed a defined amount of water, and it is always the lower of the two. Glycol-based brake fluid is hygroscopic: it draws moisture out of the air through seals and hoses over time, so a braking system that has not been bled in years is running on something nearer its wet figure than its dry one. That single fact is why brake fluid has a service interval published by the machine's manufacturer, and this site points at that manual rather than setting an interval of its own. The specifications themselves follow a rule that is worth stating because getting it wrong is expensive. DOT 3, DOT 4 and DOT 5.1 are all glycol-based and can be mixed, with the resulting system taking on the properties of the lowest specification present. DOT 5 is silicone-based, is not hygroscopic, and must not be mixed with any of the others — the names are adjacent and the products are not. Beyond the specification, makers publish their own dry and wet figures, which are frequently well above the minimum the DOT number requires, and those are the comparable numbers within a specification. We compare the DOT specification, published dry and wet boiling points, base type, mixing rules as published, and container sizes.

These parts compared, figure by figure

1. 

   Liqui Moly SL6 DOT 4, 5 L

   A five-litre DOT 4 brake fluid published against FMVSS 116, ISO 4925 Class 6 and SAE J 1703/J 1704, with car manufacturer recommendations listed.

   Specifications

   FMVSS 116 DOT 3 / 116 DOT 4 | ISO 4925 Class 6 | SAE J 1703 / J 1704 (maker’s bullet)

   Class

   ISO 4925 Class 6 — higher than the Class 3/4 published by the other fluids in this family

   Volume

   5 litres (from the title)

   Stated recommendations

   Audi, BMW, GM Europe, Seat, Skoda and VW approvals — all car manufacturers (maker’s bullet)

   Boiling points

   Stated extremely high wet and dry boiling points — no figure is given (maker’s bullet)

   Miscibility

   Miscible and compatible with high-quality synthetic brake fluids (maker’s bullet)

   Amazon reference

   B07N94TH1L (one reference across 5 Amazon marketplaces)

   EAN

   4100420211690

   • Publishes three standards and an ISO class above everything else here
   • States miscibility with other synthetic fluids explicitly
   • Wet and dry boiling points are described as extremely high and never given as numbers

   Best for: A full brake and clutch bleed where the machine’s manual permits a Class 6 DOT 4.

   ≈ €49

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2. 

   ATE SL DOT 4, 5 L

   A five-litre DOT 4 brake fluid whose bullets consist of the product name twice, a quality claim and a claim of ergonomic design — with no standard or boiling point published.

   DOT grade

   DOT 4 (from the title)

   Volume

   5 litres — 5000 ml (from the title)

   Standards

   NOT published in the bullets — no FMVSS, no ISO 4925 class, no SAE reference.

   Boiling points

   The maker puts nothing in writing on this.

   Listing bullets

   Four: "ATE brake fluid SL 5 ltr", "ergonomic design", "high quality", "ATE brake fluid SL 5 ltr".

   Miscibility

   The maker puts nothing in writing on this.

   Amazon reference

   B003VXPY4K (one reference across 6 Amazon marketplaces)

   EAN

   4006633490030

   • From a brake manufacturer that publishes its own technical data
   • A five-litre container for a workshop or several machines
   • No standard, no ISO class and no boiling point published anywhere in the listing

   Best for: A rider who already uses this fluid and is re-ordering it by name.

   ≈ €32

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3. 

   Bosch DOT 4, 500 ml

   A 500 ml DOT 4 brake fluid published to three standards with a dry boiling point of at least 230 °C and a stated two-year replacement interval.

   Dry boiling point

   ≥ 230 °C (maker’s bullet) — the only boiling point published in this family

   Standards

   FMVSS § 571.116 DOT 4, SAE J 1704, ISO 4925 Class 4 (maker’s bullet)

   Replacement interval

   Every 2 years, with the vehicle manufacturer’s own requirement taking precedence (maker’s bullet)

   Volume

   500 ml (from the title)

   ABS

   Inhibitor components stated to act as a protective lubricant against noise, wear and corrosion (maker’s bullet)

   Stated compatibility

   Suitable for vehicles manufactured before 2010 (maker’s bullet)

   Amazon reference

   B00P3XXJFC (one reference across 6 Amazon marketplaces)

   EAN

   4047025114592

   • Publishes a dry boiling point in degrees — the only fluid in this family to do so
   • Publishes a change interval AND defers to the vehicle manufacturer on it
   • The wet boiling point is not published, and that is the figure that degrades

   Best for: One brake bleed on a machine specified for DOT 4, opened and finished the same day.

   ≈ £13 / €11

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4. 

   MANNOL 3002 DOT-4, 5 L

   A five-litre DOT-4 hydraulic fluid published to SAE J1703/J1704, ISO 4925 Class 3/4 and FMVSS 116 DOT 3/4, stated for conventional brake and clutch systems.

   Specifications

   SAE J1703/J1704, ISO 4925 Class 3/4, FMVSS 116 DOT 3/4 (maker’s bullet)

   Stated use

   All conventional hydraulic BRAKE AND CLUTCH systems (maker’s bullet)

   Volume

   5 litres (from the title)

   Viscosity

   Stated excellent viscosity-temperature behaviour — no figure given (maker’s bullet)

   Protection

   Stated to prevent vapour lock and protect against corrosion and oxidation (maker’s bullet)

   Boiling points

   The maker puts nothing in writing on this.

   Amazon reference

   B00GHXBIJG (one reference across 4 Amazon marketplaces)

   EAN

   4036021889429

   • Three standards published, including the ISO class
   • Names hydraulic CLUTCH systems explicitly, which many motorcycles have
   • No boiling point published

   Best for: A machine with a hydraulic clutch as well as hydraulic brakes, both bled at once.

   ≈ €33

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5. 

   Liqui Moly DOT 4, 500 ml

   A 500 ml DOT 4 brake fluid published to three standards with a viscosity figure of 1800 mm²/s, stated miscible with high-quality synthetic brake fluids.

   Viscosity

   1800 mm²/s (from the title)

   Specifications

   FMVSS 116 DOT 3 / 116 DOT 4 | ISO 4925 Class 3 / Class 4 | SAE J 1703 / J 1704 (maker’s bullet)

   Volume

   500 ml (from the title)

   Miscibility

   Miscible and compatible with high-quality synthetic brake fluids (maker’s bullet)

   Low temperature

   Stated excellent low-temperature behaviour (maker’s bullet)

   Boiling points

   Stated extremely high wet and dry — no figure is given (maker’s bullet)

   Amazon reference

   B07L4T6LPF (one reference across 6 Amazon marketplaces)

   EAN

   4100420211560

   • Publishes a viscosity figure, which no other fluid in this family does
   • Three standards including the ISO class
   • Boiling points described rather than given, where one rival publishes ≥ 230 °C

   Best for: One brake bleed, on a machine that sees cold mornings.

   ≈ €7

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