ok, I got a break master cylinder of a CRX just like mine, '91 CRX Si, from junkyard. I am going to change the master cylinder tomorrow. Does anyone know how to bleed the breaks so that get all the break fluid out, or do I have to? Also, what do i need to do after I have to do after I have the master cylinder in? I can use any other tips that you can give me as well, thanks.

-RAWbertCuBus

 

before i continue, its BRAKE master cylinder. also, i dont ever recommend using a junkyard brake part, i think this should be obvious, but its up to you.

youll need to buy a 10mm FLARENUT wrench. its a special box end wrench that has a bit of an opening. it is a MUST, or else you will strip the brake line nuts going into the master cylinder.

removal will be simple. use the flarenut wrench and disconnect the lines and unbolt the MC.

you should do what is called bench bleeding the master cylinder. http://www.misterfixit.com/brakbld1.htm heres a page that explains it. if you dont, you may still have air in the system and get mushy pedal no matter how much you bleed the calipers.

then hook it up. now youll need to completely bleed the system. use any DOT 3 fluid. dont bother with anything else like synthetic. if you needed to use it, youd know already. DOT 3 is fine for the street, but you should get it NEW and SEALED.

to properly bleed the system, you can do several methods, best method is the simplest, but it requires two ppl. first person to push the pedal, the other to open and close the bleed nipple. you need to bleed all 4 brakes. so you can either put the whole car on jackstands and take all the wheels off at once, or go around to each wheel and remove and replace them one at a time as you bleed that caliper.

the procedure for bleeding one caliper is:
1) remove the brake master cylinder cap and make sure its fairly full of clean brake fluid.
2) pump the brake pedal firmly but slowly several (4-6) times. do not rapidly pump it.
3) hold the pedal down and keep constant pressure.
4) now the other person will crack open the bleed screw. upon relieving the pressure, the fluid will start coming out. you should be using clear air hose atached to the end of the nipple to empty into a bottle.
5) meanwhile, the brake pedal will start to sink. BEFORE the pedal sinks completely, about 3/4 of the travel close the bleed screw tightly.
6) repeat this procedure a few times or until the fluid comes out consistent and clean, free of any air bubbles, even the very small ones.
7) VERY IMPORTANT: after a few iterations, REFILL the MC reservoir. if you let it go empty again and suck air into the system, you will have to repeat the procedure for EVERY caliper.
8) once you think youre done with that caliper, close the screw tightly and move on to the next caliper.

the order of calipers you should bleed are right rear, left front, then left rear and right front. this is because the brake lines are separated by diagonals and should start from the furthestmost caliper first.

good luck, if the brakes are mushy, then you probably didnt bleed the system well, and need to repeat it all over again.

hmm... have i left anything out?