sjwelna Posted April 16, 2012 Share Posted April 16, 2012 Need to adjust your clevis if there is to much take up for your taste. The pedal freeplay is minimal, maybe 2-3mm at most, it's not that. -Steve Link to comment Share on other sites More sharing options...
Scooby2.5 Posted July 11, 2012 Share Posted July 11, 2012 The Brake booster is the same between the WRX and STi. The MBC is bigger on the STi. I don't believe the above is totally true from the research I have done While this WRX booster looks like an STI booster the label seems to suggest its not the exact same. 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 Link to comment Share on other sites More sharing options...
Dade Posted September 8, 2012 Share Posted September 8, 2012 Subscribed Link to comment Share on other sites More sharing options...
sjwelna Posted September 10, 2012 Share Posted September 10, 2012 As a follow up (long term) to my other posts, just did a fresh flush yesterday with some ATE superblue and it helped firm up the pedal some more. The Valvoline fluid I had in it was fine but there was a little slack at the beginning of the pedal travel, possibly some air left in the lines or just not as good fluid, who knows. Still feels awesome and I love the difference. -Steve Link to comment Share on other sites More sharing options...
iNVAR Posted September 16, 2012 Share Posted September 16, 2012 Hmm I need to go through this thread again, but has anyone mentioned that having a larger MC actually means less hydraulic multiplication and effectively less force applied at the brakes per pound of force applied at the pedal? http://science.howstuffworks.com/transport/engines-equipment/hydraulic1.htm I guess maybe the booster swap makes up for less force being applied overall? The pedal may feel firmer with less travel, but you have to apply more force to generate the same amount of braking force. At least that's my read on things... Link to comment Share on other sites More sharing options...
danny boy Posted September 16, 2012 Share Posted September 16, 2012 I think our legs are all strong enough to exert sl more force- for me it's about getting rid of that mushy pedal feeling, giving a better 'feel' for how much braking is being done... That said, I have yet to do this mod- did the GS mc brace on one (decent improvement), will prob eventually do the mc/booster swap on the other- will report back when I (finally) do it... Link to comment Share on other sites More sharing options...
Power6 Posted September 16, 2012 Share Posted September 16, 2012 The pedal may feel firmer with less travel, but you have to apply more force to generate the same amount of braking force. At least that's my read on things... Yes that is the entire point of this mod. You are only describing one side of this, the hydraulic pressure is a mechanical lever. The lever trades motion for force multiplication. In increasing the force required you are reducing the pedal travel required for the same braking power. The light pedal with long travel is the "mushiness" that many don't like. Changing the MC bore for another production part isn't enough to make it too hard to stop. Lots of Subie guys have changed out the 15/16 for 1 and 1 1/16 bore for years now. The booster adds another dimension since we are dealing with assisted brakes, the STI booster may have more or less assist designed in. Link to comment Share on other sites More sharing options...
iNVAR Posted September 16, 2012 Share Posted September 16, 2012 Interesting... I think I'm coming around to seeing how shorter pedal travel with a slight increase in required foot pressure makes for better brake modulation. It's easier to have your foot in a relatively static location and increase the pressure applied...(large MC) as opposed to having to actually move your foot for the extra travel even though the pressure required would be less. (smaller MC) Link to comment Share on other sites More sharing options...
fahr_side Posted September 16, 2012 Share Posted September 16, 2012 Correct. The stock brake MC and booster is sized for the worst case scenario where the driver is a bulemic 35kg model who can barely lift her high heels off the ground, let alone push a pedal. Have a drive in an STi some time. Still really easy to get to high line pressures with reasonable pedal effort. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
iNVAR Posted September 16, 2012 Share Posted September 16, 2012 I'm satisfied with how it feels right now with the GS MCB, can't justify spending more to firm up the pedal anymore, hehe. Link to comment Share on other sites More sharing options...
fahr_side Posted September 16, 2012 Share Posted September 16, 2012 Think yourself lucky you don't have the stupid auto-panic-brake-for-skinny-schoolgirls that I have to put up with. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
iNVAR Posted September 16, 2012 Share Posted September 16, 2012 lol the what?? Link to comment Share on other sites More sharing options...
fahr_side Posted September 16, 2012 Share Posted September 16, 2012 lol the what?? '08 WRX has this. Subaru calls it Brake Assist. I have a reward ready for whoever can disable this 'feature'. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkiboym Posted September 17, 2012 Share Posted September 17, 2012 '08 WRX has this. Subaru calls it Brake Assist. I have a reward ready for whoever can disable this 'feature'. you didn't mention caring about any other "features" (ABS, cruise control, etc), so your solution is to remove the fuse. voila, no more hill-assist. now, where do i collect my reward? Link to comment Share on other sites More sharing options...
fahr_side Posted September 17, 2012 Share Posted September 17, 2012 I'm okay with cruise control and ABS thanks. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
iNVAR Posted September 17, 2012 Share Posted September 17, 2012 (edited) '08 WRX has this. Subaru calls it Brake Assist. I have a reward ready for whoever can disable this 'feature'.Ohh, interesting, just looked it up... Hmm, not sure how I feel about it. I guess in theory it's a good idea but in practice it probably sucks hehe. you didn't mention caring about any other "features" (ABS, cruise control, etc), so your solution is to remove the fuse. voila, no more hill-assist. now, where do i collect my reward? You're confusing hill-assist with brake assist. Different things. Psst, fahr, just stumbled across your 2 year old post on clubwrx, trying to figure out how to disable it haha. Edited September 17, 2012 by iNVAR Link to comment Share on other sites More sharing options...
fahr_side Posted September 17, 2012 Share Posted September 17, 2012 Ohh, interesting, just looked it up... Hmm, not sure how I feel about it. I guess in theory it's a good idea but in practice it probably sucks hehe. That quick tap on the brakes to transfer weight forward in fast transitions gets very difficult to get right with the ABS pump kicking in. Psst, fahr, just stumbled across your 2 year old post on clubwrx, trying to figure out how to disable it haha. LOL. Yeah. That worked out well eh? Remember the good old days when you were the only one controlling your brakes? Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
monkiboym Posted September 18, 2012 Share Posted September 18, 2012 You're confusing hill-assist with brake assist. Different things. you're right. i need more sleep and pay closer attention. sorry, guys! Link to comment Share on other sites More sharing options...
PearlBlueGT Posted November 4, 2012 Share Posted November 4, 2012 what about using this check valve http://www.oreillyauto.com/site/c/detail/DOR3/80189/N0284.oap?ck=Search_check+valve_1430731_2924&keyword=check+valve http://images.oreillyauto.com/parts/img/medium/dor/80189-001.jpg http://www.oreillyauto.com/site/c/detail/DOR3/80189/N0284.oap?ck=Search_check+valve_1430731_2924&keyword=check+valve# Link to comment Share on other sites More sharing options...
integroid Posted November 4, 2012 Share Posted November 4, 2012 Dont think the inlet/outlet size is correct. Essentially any check valve will work if you can find on that will fit inline. I looked everywhere and just gave up and got the right part. Link to comment Share on other sites More sharing options...
kleinerbastler Posted November 4, 2012 Share Posted November 4, 2012 Very interesting thread, got anyone news for the vdc guys? Has the new sti with vdc a mbc/booster that will fit to the vdc legacy with 12mm fittings? Link to comment Share on other sites More sharing options...
Power6 Posted November 5, 2012 Share Posted November 5, 2012 The 08+ STI does have a compatible MC, but it is essentially the same as the Legacy MC, 15/16" bore. This is the only size bore available thus far for the VDC cars, so there is nothing available to swap. That is last I checked circa 2011 but I sold my WRX...one might want to look at the BRZ it has VDC and likely has a compatible brake system from what I have seen... Link to comment Share on other sites More sharing options...
ibr_adam09 Posted November 21, 2012 Share Posted November 21, 2012 My engine is out, so I'll be doing this. Just bought this http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251174870721 it's the right one, correct ? "says it was pulled from a 05 sti" other than the sti check valve being shoved into the lgt line, it's all a direct plug and play, correct ? Link to comment Share on other sites More sharing options...
integroid Posted November 21, 2012 Share Posted November 21, 2012 Yes and yes. Looks like it will work fine. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted November 21, 2012 Share Posted November 21, 2012 My engine is out, so I'll be doing this. Just bought this http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251174870721 it's the right one, correct ? "says it was pulled from a 05 sti" other than the sti check valve being shoved into the lgt line, it's all a direct plug and play, correct ? See my previous post I think in this thread. Make sure it has if I remember correctly SJ and the certain number on it and also many had a Bosch sticker Otherwise it may not be an STI one and the WRX one is not the same. Also when you get yours compare it against the pictures on your eBay listing as I got sent a different one that the one pictured when I purchased off eBay and had to get a refund Link to comment Share on other sites More sharing options...
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