I am trying to choose a brake fluid for my track day car, this AP600 seemed the right thing, but you state it is not for road use, is there any particular reason why?
The AP600 is a high spec racing fluid and it is intend for race applications where the brake are bled and the fluid changed each time the race car is used. It has no approvals for use as a long term day to day road car fluid, It is more hygroscopic and will absorb air/moisture more than a fluid designed with road car use in mind. If you want a decent fluid more in the road car line the Castrol React (previously known as Castrol Racing Brake Fluid) would be a good starting point, if this is still not solving the problem then a change to Castrol SRF would be needed. The Castrol SRF will offer you a super high boiling point and it will be stable to leave in the system, but it is expensive.
Archived in: Castrol React Brake Fluid29th April 2014