BF51L 1L Dot 5.1 Synthetic Brake Fluid

Don't know what to say about Comma brake fluid, it works and it's a good price. What I will say is all Comma products, oil, coolant, engine flush etc work extremely well and are a good price. If you take a look at there website you can find the right product for your vehicle by entering your reg number, makes life easier :)

Great value performed well no complaints

I can only assume it's good as it's not really the kind of thing you can evaluate, but this 5.1 was the same price as dot 4 so I replaced all the fluid, if I crash and die from brake failure I'll have the coroner update this review.

This actual product is *good*, but it isn't great, and buying it for the Dot number of 5.1 over many Dot 4 fluids is, counterintuitively, not the smart choice. The *minimum* specifications for a Dot 5.1 brake fluid is a boiling point between 190°c "wet" (meaning that the fluid has absorbed water naturally, as all glycol based fluids do) and 270°c "Dry" meaning it is new and hasn't absorbed water. When brake fluid boils it is possible to lose almost all braking ability, and when it is wet it corrodes the brake lines, so wet and boiling brake fluid is just dangerous. As brake fluid really loves and attracts water, this is an important reason to regularly change your brake fluid, and the reccomended time-scale is to test every year and replace every two years. According to Commas own specification sheet, available on it's website for anyone to view, the specs for this fluid are a boiling point wet (saturated) of 183°c and a spanking fresh and dry 275°c. Now these are adequate, but there are Dot 4 fluids out there for comparible prices that outperform the minimum specifications for Dot 5.1 fluids, and so this fluid also by a simply staggering margin. Also worth noting is that Commas own Dot 4 brake fluid is almost as good as their Dot 5.1 as the brake fluid dry boiling temperature is only 5°c lower at 270°c, and it's wet boiling point is at 160°c, 23°c lower. If you maintain and check your fluid every year to two years, there is no point spending 50% more for their barely superior Dot 5.1 fluid over the Dot 4 I *should* have bought for the price of a much better product. The minimum specs for dot 3, 4, and 5.1 are as follows" DOT3: Dry - 205 °C, Wet- 140 °C DOT4: Dry - 230 °C, Wet - 155 °C DOT 5.1: Dry - 270 °C, Wet - 190 °C Castrol SRF Dot 4 brake fluid has a WET boiling point of 270°c, and a dry boiling point well north of 300°c. Now while this example is up to four times as expensive as Commas 5.1, if you are looking for the *best* fluids for your car, (as I can only assume that you would be when looking for Dot 5.1 fluid over Dot 4 fluid) price isn't the most important factor, safety and quality is. Another, cheaper Dot 4 fluid out there has a minimum wet boiling point that exceeds this product and only cost a small amount more. Motul RBF600 with a wet boiling point of 216°c, and a dry boiling point of 318°c. Far more acceptable. My advice is to be careful when it comes to brakes and brake fluids. Just because it is advertised as better, it doesn't mean it really is worth that hike in price.

Bought to use with sram dot brakes, much cheaper than buying cycle branded stuff and is just the same, worked perfectly in bleeding both brakes and they are better than ever

Perfect for what I needed☺️

This DOT 5.1 replacing DOT 4 : used in a Mercedes. apparently this is a higher specification than standard DOT 4 (it has higher boiling point, and 'reacts' more quickly to braking). Some rumors are that this can be more severe on rubber seals, though I have not witnessed this and it seems rare (maybe only if the seals were old anyway ?) TIP: check you capacity this 1L bottle (just!) was enough to replace & flush all four brakes, so go sparingly when pouring. USE A FUNNEL as all brake fluid is highly damaging to paint work etc. WOULD recommend.

Price

Lo compre para los frenos de la bicicleta dado que estos usan dos 5.1, y dado que todo lo que sea para bici tiene un precio muy excesivo me decante por este. Por ahora me van excelente, y tengo aceite para muchos purgados.

4 años de uso lleva y la verdad que totalmente correcto, nada que objetar y el precio lo considero correcto

Estupendas prestaciones a un precio muy competitivo Sirve perfectamente para la gran mayoria de coches, lo recomiendo sin dudarlo ni un momento

Buenas prestaciones como cualquier liquido dot 5 de marcas superiores está bien para hacer el cambio bianual y limpiar el circuito