DOT3 or DOT4?

Manual says "Ford Heavy Duty Brake fluid", so not much help there...

Should say it on the master cylinder resevoir cap.

Dot 3 on my cap. 98 LSC

I use Silicone Brake Fluid (DOT 5?) in my show cars as they sit for long periods and Silicone does not have the moisture issue reg fluid has. I replaced everything Master cylinder lines flex hoses, calipers, etc when I switched as it is not 100% compatible with other fluids. Only issue is getting all the air out - Silicone has a tendancy to absorbe air.

Best issue for me is it wont hurt the paint!

DOT 3, DOT 4, and DOT 5.1 should work fine in our cars. One of these days I'll replace all my fluid with 5.1. Cheaper than throwing on drilled and slotted rotors.

Type, Dry boiling point, Wet boiling point:
DOT 3, 401°F, 284°F
DOT 4, 446°F, 311°F
DOT 5.1, 518°F, 375°F

Dot 5 is silicone based and I'd avoid it, but 5.1 is still glycol.

thanks for the answers guys :)

I'm pretty sure DOT 5 does not work with ABS systems