am going to take my car to the track soon,
so should I change my brake fluid from Dot 4 to Dot 5??
if so what is the easiest procedure for doing this?

 

You should use DOT 4 fluid - 'regular' fluid, not a DOT 5 silicon based fluid.
Yes, you should have the fluid changed. You will be fine with fresh BMW fluid; I'd recommend having an independent shop do this for you. At the event, ask someone to describe how to bleed the brakes yourself. It is not difficult. If you begin to experience brake fade, it's time to use a higher temperature DOT4 fluid. Most BMW folks use ATE Blue (or the amber colored ATE Type 200 - identical but for color). The dealer will not have ATE fluids.

 

Yeah, do NOT use DOT 5!

Find a good quality DOT4 and flush the entire system... I like using the Motive Power Bleeder, personally. I alternate between Ate Blue and Ate Typ 200, to ensure I get a complete flush.

My system gets a flush before autocross season starts, and again halfway through... Throw in a couple track days, and flushing every 6 months ain't a bad idea.

 

Agree to flush out the system. Going with Blue is a great idea (and a great fluid) because you can see when it has made it to all of the calipers.

DE's do check this stuff, at least BMWCCA does. I have seen them refuse cars until their fluid has been changed, so make sure you do it.

 

You can ask for DOT Super 4 ro DOT 5 non-silicon - motul for example. These are really one and the same, although there will be some minor temp differences between manufacturers. This variety of DOT super 4 has the same wet and dry boiling (+/- a few degrees) points as DOT5 Silicon. I use motul all year, although I did, and will continue to flush it before every track session.

 

In fact bmwcca require a change every 6 months

 

My personal favorite: Wilwood 570 for $6/12oz is pretty tough to beat.