What is the proper brake fluid for a BJ8? I have used Castrol LMA fluid (DOT4?) in other British cars and have used it in my BJ8. A few months ago during the replacement and bleeding of a clutch slave cylinder my local auto parts store only had DOT3 fluid which I purchased and installed. Currently the brake system may have a mixture of DOT3 and DOT4. Has any harm been done either by this potential mixing or the use of DOT3? If so can this be rectified by the draining of the fluid and the installation of DOT4? Thanks.