Urgent - Dot 3 Brake Fluid?

[Younes]

I replaced the brake master cylinder yesterday on my car, but it says use only Dot 3 fluid ( I realised that later).. I put Dot 4 in, will this damage the seals in the master cylinder?

[timson]

DOT 4 is interchangeable with DOT 3, but if a vehicle specifies DOT 4 you shouldn't use DOT 3. The difference is boiling points. I don't have the numbers here and manufactures can vary but DOT 4 always has a higher boiling point then DOT 3,

No damage to seals

[Younes]

Thanks mate... :)