After running my engine, i can cut it off, and i hear a hissing sound from around my brake booster, and my brakes dont work too good, but they are fine when the truck is not running, it builds up pressure good? What could it be? Awww, and I am wanting to put an eletric fan on my truck, its a 1989 Mazda B2600i 4-wheel drive....2.6 Liter, would it hurt to put one on it, would it cool enough? Any informatin would be great!!! thanks Michael

 

sounds like a bad brake booster
when you apply the brakes do you here the hiss sound or does the engine stumble this would indicate a bad diaphram in the booster

as for the fan are you getting rid of the old clutch fan and replace with the electric one or did you want both fans
there are some nice fan kits out there i've been looking at removing the clutch fan myself and going electric but gotta find out more about the temp setting(adjustable) for when the fan kicks in to cool down right now my truck will heat up between 1/2 and 3/4 which i think is normal