Has anyone out there change out the brake fluid? How hard to do? Any good site for procedure? This is for Mazda B2300 '94, 270K miles.

 

Its rather easy. Best to have a friend help...(as long as they can follow directions).

It just takes time, and patience.

You can buy a pressure bleeder that attaches to your master cylinder to make it a one person job. but if you're not a professional whats the point of spending 80 bucks on one?

basic instructions are
1. suck old fluid out of Master cylinder reservoir
2. put new fluid in MC (making sure it is of the correct grade for your car - most are DOT 4 now) replace cap to MC
3. start at the furthest wheel from the MC (pass rear) break the bleeder screw loose, and lightly retighten. Then have friend put pressure on the brake pedal, open bleeder, the person on the brake pedal needs to say "down" when the pedal is getting to the end of its throw. once he does this he needs to keep his foot on the pedal until the person @ the screw tightens the bleeder and says "okay". He then lifts the pedal and the procedure is repeated. Your current fluid will be dark like coke, or coffee. the new fluid as you should now know is light in color. You will repeat the above until you get the light colored fluid @ that wheel. then go to the next furthest wheel from the MC

IMPORTANT NOTES:

Typical order is Pass rear, driver rear, pass front, driver front.

WATCH THE MC fluid level. if it runs out you will get to start all over, as ANY air in the brakes leads to a squishy pedal feel...and overall poor braking performance. so don't let it get below 30% full. (or 70% empty)

Don't use old fluid - if the container has been opened throw it away. Brake fluid absorbs water. water is evil.

 

Thanks for the info, it's very helpful. I have few questions for you.

(1) You say, "WATCH THE MC fluid level. if it runs out you will get to start all over, ..." Start all over = pour more brake fuild in Master cylinder reservoir, right?

(2) The engine should be off when doing this, right?

 

When I say start over, I mean go back to the farthest wheel and completely start over (after refilling the MC), and ensure no air has entered the system (once its entered @ the MC its there until you get it out @ the wheels)..so if some has entered when you ran the MC dry, you must get it out. IF you have ABS this can get more complicated as Air LOVES the small channels in the ABS unit. it can be a PITA to get out. RULE is DON"T LET IT GO DRY. once you do it, you'll be so pissed, you'll want to scream profanities at the top of your lungs for 20 minutes (this was what I did at least).

Some cars like to spit fluid out of the MC so make sure you put the cap back on.

Engine can be on or off. there is no reason to turn it on.

 

When I look at the Master cylinder reservoir, it's pretty small plastic bottle. So, I will empty out the old fluid in the reservoir and add new fluid (it will be small amount). Therefore, most likely I have to re-fill at least few times. Correct? BTW, I have ABS system.
'94 B2300 Short bed, 270K miles.

 

I suggest sucking the old out with a syringe, or turkey baster, and adding fresh before doing anything else...no reason pumping more old out than you have to.

Yes, you'll need to keep an eye on the level. likely add some between each wheel (maybe more often) again keep an eye on it. (easier to make the guy in the drivers seat look at it, since you'll be on the ground.

 

There are a min and a max lines on the reservoir. I guess once I see the level hits min line, I will stop and add more fluid. As far as when to switch wheel, I will say once I see clear fluid come out, I will move to the next wheel. Right?

 

you are correct on both accounts