I am going to change out the brake lines on my STi to StopTech’s SS lines. As I’m doing this, I also plan on changing the brake fluid to Motul 600.
What would be the best way to flush out the system?
Do I just drain the master cylinder and keep bleeding the brakes until the new fluid passes (would this cause any problems because of mixing)?
Dose the ABS system have a reservoir?

 

Disconnect the brake lines from the calipers and put them in jars for the fluid to go. Start flushing the brake fluid out fallowed by alcohol to clean the system, let the alcohol completely dry. To put the new fluid in I would bench bleed the master cylinder with the new fluid and then put it back on the car. From there I would install the new brake lines and then bleed your brake lines until all of the air is out.

 

Since you are doing lines, you will probably go through more fluid than just bleeding - I would (and will shortly, actually - I have a set of Stoptech lines and speedbleeders to install) replace all the lines, keeping an eye on the brake fluid reservoir and making sure it doesn't go dry - once the lines are all on there, remove the old fluid from the reservoir using a turkey baster or syringe, then fill it up with the new stuff - then bleed each line until the new fluid comes out. For the abs, some systems have closed channels which only open up when the abs cycles - I believe if you pull the fuse to the abs, the system cycles when you re-install it (system needs to be under power, I imagine).

There is really no need to wash the system out with solvent - for one, no telling what that solvent will do in the system (if it's even effective at removing the fluid or if it will damage seals) plus, bench bleeding the master cylinder can be a serious pain - if you do what I describe above, you will get 99%+ of the old fluid out, and not introduce any air bubbles into the master cylinder.

 

Alcohol+Rubber=bad!!!!

The alcohol does a couple things that I wouldn't want on any crosslinked polymers (rubber)....first it removes excess moisture (water) from the bulk material, causing it to dry out and eventually turn into a crumbly mess. Second it breaks the polymer chains, which helps in the decomposition of the first point. I'm thinking denatured ethanol if you really wanted to be that **** about cleaning out the system. DrD's method is A+, who cares if you get a little motul mixed in with your stock fluid anyways?

 

So are you saying that just put the new lines in, then bleed all the fluids out of the system then put in new fluid?

The former - you will loose a bunch of fluid installing the lines - it might as well be the old stuff! Change the lines, then change the fluid - it's cheaper that way!)

Or just bleed the brakes until all the bubbles are gone then use something to take out the old fluids inside the reseirvor tank? Hpw do you get all the old brake fluids out? Do i need a tool that will suck it out or can use so other?

When you go to bleed the brakes, suck the old fluid out of the resevoir (or you can push it all out one line - it's just faster to suck it out), then fill the resev. with the new fluid - then bleed the brakes - keep pushing fluid through each line until the new fluid is coming out, and the old is gone.

What were you talkin about when you were saying let the abs cycle? Do we have to do that to put in new fluids like motul 600?

Most abs controllers have some channels in them which are normally closed, but filled with fluid - they only open when the ABS system operates - so you change the fluid, bleed the system, then cycle the abs (pull the fuse, go play on a dirt road or in the snow, etc.) - this pumps the old fluid into the lines - then you bleed all 4 corners again, and the system is done. (you don't need to do the abs thing, as it's not much fluid, and most brake fluids are compatable with one another, but if you are going through the trouble of making the swap, you might as well do a complete job)

 

so its ok to have a little of the stock fluid (dot 3) mixed with the motul (dot 4).

On the STi where is the ABS fuse?

 

hwo do u bleed the brake fluid? just pump the brakes while the brake lines are disconnected?

 

No - that will get lots of air into the system. There is a decent review on scoobymods - just read the whole thread first, as there is an error in the leading post

http://www.scoobymods.com/forums/sho...=6623#post6623

 

you need two ppl.. just pump and open at same time. when u lift foot off pedal have the bleed screw closed. that's to get fluid in or to just bleed.
if u are changing the lines, i would just pump the pedal with the bleed screws open until the fluid's gone then change the lines.. that way it's not as messy..