What ever you want to use is fine. Originally used DOT 3. DOT 4 is compatible, a little more expensive and a higher boiling point. DOT 5 is a purple synthetic, not compatible, most expensive, does not absorb moisture so doesn't have to be changed, more lubricity for less system wear, won't harm paint work if it leaks. The downside is system must be flushed out and new rubber seals used, tiny air bubbles tend not merge into larger one which can make bleeding a little more difficult (may be a concern with single rear bleed valve on out cars), has a little more compressibility which may be negated by using braided steel lines in place of rubber. There is lots of urban legends on DOT5 out there some which started when it first was used and is no longer valid. I know a number of people who use it successfully in their classic cars. I chickened out when I rebuilt my brake system due to the reported difficulty in bleeding our rear brakes but I never had a problem as it turned out. I wonder if I should have used it (but then I wouldn't have the fun of bleeding brakes every two years).
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT
