Which Brake Fluid To Use

[P14NJH]

hi guys

i want to bleed the brakes on my 1999 IS200 SE, i have read somewhere i need to use brake fluid DOT 3, however on a trip to Halfords, thy have told me DOT 3 is hard to get hold of now, i have looked at a can of DOT 4, which has exactly the same serial/code numbers as on the recomended DOT 3 brake fluid.

do i need to use the DOT 3 or would i be alrite with the DOT 4.

[TonyGoose]

If memory serves the DOT3, DOT4 and DOT5.1 are all compatible mineral fluids.

DOT5 is the synthetic fluid which I think was best not to be mixed with the others.

TG

[Rob]

^^^^ what he said. DO NOT USE DOT 5 as you can not mix it with other fluids and is not compatible with the seals in your system

[dave1]

Phone your Local Lexus dealer and ask what they use?

[rig-pig]

dot 4 will be ok to use thats what all the garages use

[TheDon]

^^^^ what he said. DO NOT USE DOT 5 as you can not mix it with other fluids and is not compatible with the seals in your system

ahhh.. but now you have DOT 5.1 brake fluid that is mixable and completely compatable with 3&4..

I have changed my bikes to DOT 5.1 as it gives a lot better feel to the brakes... not sure if it would be any better for the cars? its a lot better than dot 3 or 4 for heat & moisture absorbing properties

http://www.motul-oil.co.uk/motul%20data%20...8070%20(GB).pdf

Not to be confused with DOT 5, a silicone based fluid.

DOT 5.1 is one of several designations of automotive brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point.

A brake fluid's dry boiling point is the temperature at which the pure fluid will boil. Wet boiling point concerns the boiling temperature when the fluid contains water.

In the United States, all brake fluids must meet federal standard #116. Under this standard there are three Department of Transportation (DOT) minimal specifications for brake fluid. They are DOT 3, DOT 4 and DOT 5.1.

DOT 5.1, like DOT 3 and DOT 4, is a polyethylene glycol-based fluid (contrasted with DOT 5 which is silicone-based). Polyethylene glycol fluids are hygroscopic and will absorb water from the atmosphere, which is necessary to prevent sheer and undiluted water in the braking system, which is very corrosive.

As of 2006[update], most cars produced in the U.S. use DOT 3 brake fluid.

Dry boiling point Wet boiling point

DOT 3 205°C (401°F) 140°C (284°F)

DOT 4 230°C (446°F) 155°C (311°F)

DOT 5 260°C (500°F) 180°C (356°F)

DOT 5.1 270°C (518°F) 191°C (375°F)

[Rob]

i know you get get 5.1 thats why i put dont use DOT5

[TheDon]

i know you get get 5.1 thats why i put dont use DOT5

Sorry.. what i meant to say is that there is "also" DOT5.1 as an option to the DOT 3 & 4..

Not too many people seem to know about it for some reason?

I will be using it on my GS when i get round to bleeding the brakes fully in spring (hopefully with new hoses s/s)