How often should I change the coolant and brake fluid?
I checked the maintenance manual. It does't mention these 2 fluids at all.

 

Coolant is generally good for five years.

Brake fluid should be flushed when you change pads. More often if you track the car.

My pads were good to 100K miles - so it was a good time to flush...

 

modern coolants are good for 5 years. brake fluid is usually recommended every 2 or 3 years by most manufacturers..

 

Like Veronica, I usually replace brake fluid when I replace brake parts (pads/rotors/etc) but as also mentioned, 2-3 years is generally the recommended interval. Many people will never change their brake fluid unless there is a failure that requires it (caliper, master cylinder, whatever) but if you are looking for a "standard" to go by 3yr/36k miles is a good starting point.

As far as the 3/36 rule, I also try to use that for coolant service because I also replace the thermostat along with the coolant to keep up with temperature maintenance due to the severe heat cycles our engines go through regularly.

 

I spoke to a Mazda tech a couple months ago and like 03chi-town0Z mentioned, he will never change brake fluid unless there is something wrong that needs fixing and thus topping up.

 

are the brake lines on the RA something i should look to replace?

 

Have not been a failure item...

If you mean hoses - a switch to steel-braided hoses will improve brake feel.

I flush brake fluid for one main reason, Corrosion. Brake fluid is anhydrous (collects moisture and keeps it entrained). This will eventually rust even stainless steel lines. Also, seal wear puts 'dirt' in the fluid which will accelerate wear on the seals and pistons.