ATF as brake fluid for a MTB

[Rouxenator]

Back when I was a student the guy I drove to Tech with had a 3-series BMW that we serviced ourselves. I recall using ATF (automatic transmission fluid) as brake fluid and was wondering if I can do the same on my mountain bike? Its got basic Tektro hydraulic brakes and recently I really had to pump the rear one in order to get any response from it. The discs are still good and I had new pads fitted a while back. Not keen on making another trip to the bike shop so I was wondering if I could do a DIY on it. On the website it says you should use "Tektro mineral oil" and the reservoir on the bike also says "mineral oil only".

Edit : Nevermind, my mistake, we used ATF as steering fluid, not for brakes.

 

[Rickster]

Go to you local spares shop and ask for some power steering oil for a VW/Audi...they use mineral oil in the power steering units.

Make sure what you buying has no color to it the one im talking about is a clear (slightly yellow) color...dont accept any other color.

PS: Don't forget to bleed the brakes that's why "I really had to pump the rear one in order to get any response from it" you get this problem