SCHM1AN Posted June 19, 2012 Share Posted June 19, 2012 I just stopped by a local Subaru tuner shop and asked them for a quote to do this job since I don't have a garage of my own... they suggested changing pads/fluid. After I told them that the problem was the flexible firewall, they suggested buying the GS brace and installing that. What don't they understand about "I want to swap out my MC/BB for an STI MC/BB" Link to comment Share on other sites More sharing options...
Swine Posted June 19, 2012 Share Posted June 19, 2012 Pads and fluid are still always a wonderful idea. But if giving your brake pedal feel a complete make over is the goal, the Master/booster swap is THE ticket. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted June 20, 2012 Share Posted June 20, 2012 - Sorry - Having driven some really sophisticated cars (including some really great-braking Porsche Carreras and BMW M series), the LGT is pretty decent. Pads and fluids get you much further than you're intimating above and the MCB really adds to that. Not discounting that the MC and BB gets you the extra 10%, but having driven an STI and my LGT B-to-B, I don't see that much of an improvement in pedal feel, the Brembos notwithstanding. My OBXT vs driving a friends LGT is worlds different. Longer pedal movement and really mushy. His is firm and far less travel. I ran the numbers and it seems that we should have the same booster and master cylinder but when you look at the numbers on each of our boosters they are clearly different. Maybe some of us have somewhat less quality/bad boosters and/or maybe the OBXT is in fact a different one. To me it is worth a shot, as I can't stand the mushy pedal feel on my wilwoods. Link to comment Share on other sites More sharing options...
boxkita Posted June 23, 2012 Share Posted June 23, 2012 Brand new Group N Brake Servo (Modified) 75 British pounds - http://www.subaruwrcspares.com/19.html http://www.subaruwrcspares.com/resources/GpN+servo.jpg Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 6, 2012 Share Posted July 6, 2012 (edited) I just put my STI master cylinder/booster in tonight after having it sit on the shelf for over a year. Everything went in without a hitch in my MY08. First impressions are good, there is still a bit of 'nothing happening' at the top of the pedal travel but then once it engages the pedal feel is definitely better, not nearly as mushy as it was before. I think with some good pads (bobcats), SS lines, and some ATE superblue, this would make for much better brakes. It wasn't as dramatic as I was expecting, but then again I just spent the weekend driving my parent's IS350 and '10 acura TL. THOSE things have touchy brakes. I flushed a full quart of new Valvoline DOT 3/4 synthetic fluid in using my vacuum bleeder, I had flushed it out a couple months prior with some crappy Wear Ever fluid and it turned back to mush within a couple months so this was a good time to swap the booster in. I flushed/cleaned the crud out of the master cylinder using the same technique of detaching it from the booster and the reservoir, putting it into a cup filled with brake fluid, and working the piston back and forth a bunch of times to work the dirt out of it. I only had to do it a couple times, there wasn't much coming out. I also did rinse/shake the reservoir out with brake fluid as it had a bit of dirt inside it. A word of warning, if you are doing the bench bleed like I did using rubber vacuum caps to plug the threaded holes for the lines, WEAR SAFETY GLASSES. I was working it back and forth and managed to blow one out of the hole and spray brake fluid all over my face and into my right eye. I washed it out right away with saline a bunch and it is fine, but that is nasty stuff you don't want in your eyes. I did have one thing to add to the whole thread, and that was that I had to "clearance" (read, hit with a hammer and bend over on itself) the back lip on the STI booster to give some more clearance to the hardlines right behind it on the firewall on the left side. I have a couple pictures I will add to this thread to show the differences clearer of the boosters. The shape of the STI booster is more flat on the back and puts part of it closer to the firewall and ran into the lines. For clarity: In the first picture, the STI booster/BMC is on the left. In the second picture, it is on the right. In the third picture, you can see where I had to fold the lip over using a hammer on the back side of the booster, from approximately 1-o'clock to 3-o'clock. This should have zero affect on it's reliability/functioning. You can see how the STI booster will be closer to the firewall.http://legacygt.com/forums/attachment.php?attachmentid=116219&d=1334456077 While this booster looks like an STI booster the label seems to suggest its a WRX booster. All the STI boosters from 04-07 had SJ as the two letter large code. They also had the numbers 061023 or FO1G061023 Some said Bosch on them I could be wrong but from the research I did before I just purchased mine this is what i found. The WRX booster looks the same but Im not sure it is totally the same. This information came from a reputable STI only parts dealer http://www.y2kimports.com Edited July 6, 2012 by Scooby2.5 Link to comment Share on other sites More sharing options...
rpoz28 Posted July 6, 2012 Share Posted July 6, 2012 Thanks for the great info. Does it look like the brake fluid resevoir from the Legacy master cylinder would snap into the STi master cylinder? Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 6, 2012 Share Posted July 6, 2012 No if you read through this thread, that is sorta what started the whole thing. You have to change the booster and master cylinder because the Legacy master cylinder will not fit the booster from what I remember. Also the Legacy master cylinder is a 15/16 piston. The STI is 1 1/16 I believe. This was also discussed and the piston size difference should account for some of the more firm pedal. Writing this from memory but if you want to be sure start reading from the OP. Hope that helps..... Link to comment Share on other sites More sharing options...
rpoz28 Posted July 7, 2012 Share Posted July 7, 2012 (edited) Thanks Scooby. I understood about the master cylinder itself needing to be swapped. I was wondering just about the fluid resevoir since that usually isn't included if you buy a new master cylinder. I saw that the question had been asked in post #37, but I didn't see that anyone had posted a response. Edited July 7, 2012 by rpoz28 Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 7, 2012 Share Posted July 7, 2012 Ooops my bad you did say reservoir. Sorry bout that. I think the reservoir is the same when I compare mine but not sure. Link to comment Share on other sites More sharing options...
vkchu Posted July 17, 2012 Share Posted July 17, 2012 looking fwd to doing this + gs brace this wk. Link to comment Share on other sites More sharing options...
vkchu Posted July 20, 2012 Share Posted July 20, 2012 is there any way to turn the booster rod to make adjustments once installed, or is it an all or nothing kind of deal, meaning it needs to be removed? i got the lockup a few experienced. hoping it will release by the morning so that i can drive it out of my parking spot. Link to comment Share on other sites More sharing options...
trackhore Posted July 20, 2012 Share Posted July 20, 2012 While I don't have the MC sitting in front of me, you should be able to disconnect the clevis pin on the brake pedal itself, turn the rod to the desired length, then re-connect to the brake pedal. Link to comment Share on other sites More sharing options...
vkchu Posted July 20, 2012 Share Posted July 20, 2012 thanks, i was able to get it adjusted. wow, almost too firm, but i like that it doesnt sink like before. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 27, 2012 Share Posted July 27, 2012 So how is it after the swap vkchu? Much better? Link to comment Share on other sites More sharing options...
vkchu Posted July 27, 2012 Share Posted July 27, 2012 So how is it after the swap vkchu? Much better? after having driven it for about a week, and gotten used to the feel, id say that it is well worth doing. i got the booster and cylinder for ~$70 on ebay - big bang for buck. i dont know what it is like on just a stock brake setup as i have other mods, but as far as feel, pedal travel, and confidence is concerned, theyre all vastly improved over the stock setup. the real test comes sat when i try them on with my track setup at summit point. im expecting it to stop like an anchor has been tossed out. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 27, 2012 Share Posted July 27, 2012 What brakes are you running?.... Did you end up setting the rod to the same length as the stock booster? I have Wilwoods up Front with porter field R4S pads like the franz has. stock LGT brakes with same pads out back and technifit lines etc. I have my booster but been lazy to put it on as I heard its not real easy getting it out. I do have a FMIC and no stock FPR to deal with so mine may be easier. My pedal has always felt mushy so Im trying this soon. Just need to do it. Link to comment Share on other sites More sharing options...
vkchu Posted July 27, 2012 Share Posted July 27, 2012 What brakes are you running?.... Did you end up setting the rod to the same length as the stock booster? I have Wilwoods up Front with porter field R4S pads like the franz has. stock LGT brakes with same pads out back and technifit lines etc. I have my booster but been lazy to put it on as I heard its not real easy getting it out. I do have a FMIC and no stock FPR to deal with so mine may be easier. My pedal has always felt mushy so Im trying this soon. Just need to do it. dba4000 slotted rotors, carbotech bobcat pads, stoptech lines, ate fluid. oem calipers. track setup is centric blanks with carbotech xp10 up front, xp8 in the rear. i dont have a place to work on stuff at my place, so i had a subie tech (i know the guy so i get a good deal on labor) do the install. also, i am not all that interested in contorting my body to undo the screws under the brake pedal so ill gladly pay for that kind of labor. the rod was initially kept as the same length as the legacy, but i ran into the dreaded lockup issue. good thing i was already home by that time, but it could be bad if the brakes lockup on the highway. waited til the morn til the pressure bled off, and then the sti rod was adjusted to be a little shorter than the legacy booster. this step requires patience and some fiddling around because depending on the pedal travel length, it may not go far enough to activate the brake lights, which is obviously bad (unless youre running from them coppers ). added in the gs brace, and now the brakes are now a-fn-mazing. consider doing it. if youre doing it yourself, give yourself a good chunk of time to do it. Link to comment Share on other sites More sharing options...
SCHM1AN Posted July 27, 2012 Share Posted July 27, 2012 Did you get the GS brace for the STI or for the Legacy? Link to comment Share on other sites More sharing options...
SBT Posted July 27, 2012 Share Posted July 27, 2012 I would think you'd still want to use Legacy GS MCB as the strut tower mounting is different between the WRX/STI and the Legacy. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
vkchu Posted July 27, 2012 Share Posted July 27, 2012 Did you get the GS brace for the STI or for the Legacy? legacy. i believe gs makes two versions - fitment with vdc and without, so be sure to get the correct one. Link to comment Share on other sites More sharing options...
atchipmunk Posted July 30, 2012 Share Posted July 30, 2012 So the GS brace DOES fit with the STi booster/MC combo! Good to know! Link to comment Share on other sites More sharing options...
SCHM1AN Posted July 30, 2012 Share Posted July 30, 2012 if youre doing it yourself, give yourself a good chunk of time to do it. Care to elaborate? I'm just trying to get an idea of how long I would need to do this. What kind of issues did you run into? Link to comment Share on other sites More sharing options...
vkchu Posted July 30, 2012 Share Posted July 30, 2012 Care to elaborate? I'm just trying to get an idea of how long I would need to do this. What kind of issues did you run into? i didnt do the install - my usual tech did the work. see post 87. that's the main issue - getting the rod length correct, testing for lockup and ensuring that the brake lights light up as expected can take some time. gl. Link to comment Share on other sites More sharing options...
TinKnocker38 Posted August 3, 2012 Share Posted August 3, 2012 thinking about purchasing the STI MC and Booster for my 2.5i with AVO Turbo kit 6psi. Still trying to locate a booster check valve, do i need one? Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 4, 2012 Share Posted August 4, 2012 Check valve for the STI comes in the STI hose. Yes you need it if you change to the STI booster/MC. Part number for the hose with the valve is in the OP. Link to comment Share on other sites More sharing options...
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