Arcteryx Posted November 6, 2015 Share Posted November 6, 2015 Sooo.. Wouldn't the 17/16" master cylinder bolt on to our stock booster? Have we determined which part actually makes the biggest difference? I just asked this on the previous page - apparently the bolt holes are different. Link to comment Share on other sites More sharing options...
TiagoSantos Posted November 6, 2015 Share Posted November 6, 2015 I just asked this on the previous page - apparently the bolt holes are different. duh! I swear I went through most pages looking for something like that I'm gonna look for pics of how the MC attaches to the booster.. Maybe an adapter of sorts would work? I really don't want to do all that work.. :| Link to comment Share on other sites More sharing options...
taka Posted November 7, 2015 Share Posted November 7, 2015 Rex MBCs won't bolt up to the LGT booster. Don't bother trying. Do it right, get the Rex booster with the 1" Rex MBC (and the check valve hose), swap the parts, bleed the brakes, love the car Link to comment Share on other sites More sharing options...
Arcteryx Posted November 7, 2015 Share Posted November 7, 2015 1"? Don't you mean 1 1/16"? Link to comment Share on other sites More sharing options...
TiagoSantos Posted November 7, 2015 Share Posted November 7, 2015 Taka used a 1" MC from a WRX instead of the 1-1/16" from an STi He says the sizing of the 1" MC and our brakes (well.. LGT brakes) should be a closer match to the 1-1/16" MC and STi brakes. You're right, it would probably be simpler. I looked at both master cylinders and an adapter to fit the WRX/STi MC to the LGT booster wouldn't be terribly complicated to machine. But yeah, I'll just wait for a bit of time to do the entire swap. Link to comment Share on other sites More sharing options...
taka Posted November 8, 2015 Share Posted November 8, 2015 I started out with the 1 1/16 from the STI. I bought a booster, MBC, check valve hose combo off ebay. Check earlier posts for my mini walk through and list of challenges I faced. I tried some basic math on the two component options (the 1" and the 1 1/16"), and just based on MBC/caliper ratios the 1 1/16 came out to be a closer match to what the STI would have - so that is what I went with. I tried it and thought "holy @#$% that is insanely sensitive". Seriously, its like 100% on or 100% off in like an inch of pedal travel. That's what prompted me to try out the WRX 1", which IMO is definitely the one to go with. It gives a far more normal feeling pedal when compared with most everything else out there - not quite, but the best option here. The math and crap does not take into account differences within the boosters, the pedal arm length/pedal fulcrum position, or other mystery differences. That is why it probably ended up being better with the 1". If anyone is interested, I can try and dig up the post I found where I got my raw data from. It was basically an excel chart showing all of the brake components and their details for Subarus from the late 90s+ Again, warning to anyone doing this: You may have to bend some hard lines back a few degrees on the firewall to fit the new booster, and the clevis pin needs to be rotated a few turns from stock or else your brakes will lock up. Again, see previous posts. I did some tests on this but can't remember off the top of my head what the results were. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 15, 2016 Share Posted August 15, 2016 Man I still have not done this. Need to get that booster off my shelf and do it, especially now that I have stop tech ST40 up front with still a mushy pedal Link to comment Share on other sites More sharing options...
SBT Posted August 15, 2016 Share Posted August 15, 2016 Mushy sounds more like air in the system. Are you pressure bleeding? - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 16, 2016 Share Posted August 16, 2016 Nah SBT, its just a crappy outback MC and booster I think..... Link to comment Share on other sites More sharing options...
SBT Posted August 16, 2016 Share Posted August 16, 2016 Roger all. And thanks for the PM. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 18, 2016 Share Posted August 18, 2016 (edited) I will say SBT, that a friend of mine has a LGT and his pedel feels real firm like the STI booster does (I have driven an outback with STI booster) Mine on the other hand feels super power assist for first 1/3 to 1/2 and then more firm. By the time you get to the more firm pedel it's way too much push and you are stopping to quick. I want the firm pedel from the start like Shawn LGT, and a friend outback with the STI booster. On all our cars we bled them by pumping and someone else opening the bleeder in the correct order Edited August 18, 2016 by Scooby2.5 Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 20, 2016 Share Posted August 20, 2016 (edited) 3) Bench bleed the MC before install or use a power bleeder. 4) Make sure the rod length on the new STI booster is the same as the LGT booster. (It will cause brake lockup problems if it's not the same) From the service Manual on Rod Length 1) Check and adjust the operating rod of brake booster. Standard L: 136.3 mm (5.38 in) If it is not within the specified value, adjust it by adjusting the brake booster operating rod. Edited August 20, 2016 by Scooby2.5 Link to comment Share on other sites More sharing options...
SBT Posted August 20, 2016 Share Posted August 20, 2016 I will say SBT, that a friend of mine has a LGT and his pedel feels real firm like the STI booster does (I have driven an outback with STI booster) Mine on the other hand feels super power assist for first 1/3 to 1/2 and then more firm. By the time you get to the more firm pedel it's way too much push and you are stopping to quick. I want the firm pedel from the start like Shawn LGT, and a friend outback with the STI booster. On all our cars we bled them by pumping and someone else opening the bleeder in the correct order I use a Motive power bleeder on mine and follow the manual for the sequencing. Pedal is always firm with nearly no (<3/8") of yield before it gets very firm and stays that way through the stroke. Modulation is linear and braking is very right now. Not E26 M5 right now, but close IME. Centric Premium rotors, with bedded-in Hawk HPS performance pads, on stock calipers with Stop Tech SS Lines are at all four corners. The GS MC brace is installed and I've never felt the need to upgrade to anything beyond this stage. I've not driven an OB or OBXT so can't comment on the pedal feel, nor the grip of the brakes, but it does sound like the OEM bits leave the driver wanting more of both. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
Scooby2.5 Posted August 21, 2016 Share Posted August 21, 2016 Yea the outback XT had the small 2.5i brakes. I first put LGT brakes on it and then the wildwood kit. I recently got a killer deal off the forum for a stop tech front BBK. In any case I have never had a firm pedal and the only thing I can attribute it to is the outback booster. Ive done a lot of research on the different boosters and what people have reported and honestly it makes no sense how some are firm and others are not. The OB booster is def a different part number than the rest. So I am going to try the STI booster. I found a good one that is a Bosch booster but been sitting on it for a few years just too lazy to make the switch I think its time I do it though..... It seems with the BBK and somewhat the wilwoods that because my booster doesn't allow for a firm pedal I get deposits on the rotor from the pads and it gets shudder. Seems to be worse if I have slotted rotors. The best most smooth use I had was the wildwood kit with Porterfield R4S pads and smooth Centric rotors. I have bedded each time per the manufacturer Anyway trying the booster soon to see how it does with the Stoptech ST40 kit. Link to comment Share on other sites More sharing options...
PearlBlueGT Posted August 27, 2016 Share Posted August 27, 2016 I use a Motive power bleeder on mine and follow the manual for the sequencing. Pedal is always firm with nearly no (<3/8") of yield before it gets very firm and stays that way through the stroke. Modulation is linear and braking is very right now. Not E26 M5 right now, but close IME. Centric Premium rotors, with bedded-in Hawk HPS performance pads, on stock calipers with Stop Tech SS Lines are at all four corners. The GS MC brace is installed and I've never felt the need to upgrade to anything beyond this stage. I've not driven an OB or OBXT so can't comment on the pedal feel, nor the grip of the brakes, but it does sound like the OEM bits leave the driver wanting more of both. You got brace for LGT? Link to comment Share on other sites More sharing options...
SBT Posted August 27, 2016 Share Posted August 27, 2016 Yes - it's the Brake Master Cylinder Brace made by Grimmspeed. This would be for the non-VDC 2005 to Mid-2007 Subaru Legacy GT. Find it here - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
l88m22vette Posted October 29, 2016 Share Posted October 29, 2016 Did you get it installed Scooby? Also, what do you guys think about an install of this on an otherwise stock XT 5EAT setup? I read through the thread but no mention of that being done. .. Link to comment Share on other sites More sharing options...
taka Posted October 30, 2016 Share Posted October 30, 2016 AFAIK, The XT already has a larger MBC. Can't remember if 1 or 1 1/16, but last I looked at my buddies OBXT it was larger (and also not necessary because the pedal felt fine) Link to comment Share on other sites More sharing options...
fenominal Posted October 31, 2016 Share Posted October 31, 2016 Did you get it installed Scooby? Also, what do you guys think about an install of this on an otherwise stock XT 5EAT setup? I read through the thread but no mention of that being done. .. I've used the STI MC and STI BB on my 5EAT OBXT. I also have a Grimmspeed brace, LGT slotted rotors, LGT calipers, and SS lines. If this is installed and not adjusted correctly, it will feel like crap. Overall, I DO think it's worth it, but it needs to be adjusted correctly. You don't want 3" travel and no feel and you don't want 8" travel and no feel. Keep in mind, this is a feel upgrade and not a performance upgrade. If you want performance, just get better pads. Link to comment Share on other sites More sharing options...
Scooby2.5 Posted October 31, 2016 Share Posted October 31, 2016 I've used the STI MC and STI BB on my 5EAT OBXT. I also have a Grimmspeed brace, LGT slotted rotors, LGT calipers, and SS lines. If this is installed and not adjusted correctly, it will feel like crap. Overall, I DO think it's worth it, but it needs to be adjusted correctly. You don't want 3" travel and no feel and you don't want 8" travel and no feel. Keep in mind, this is a feel upgrade and not a performance upgrade. If you want performance, just get better pads. He fenominal, which Grimmspeed brace did you get to use with STI booster in a LGT/Outback? Link to comment Share on other sites More sharing options...
Scooby2.5 Posted October 31, 2016 Share Posted October 31, 2016 Did you get it installed Scooby? Also, what do you guys think about an install of this on an otherwise stock XT 5EAT setup? I read through the thread but no mention of that being done. .. Not yet Link to comment Share on other sites More sharing options...
Th3Franz Posted February 11, 2017 Share Posted February 11, 2017 Attached for reference: STI brake booster rod spec -Franz The end of a Legacy http://www.youtube.com/th3franz Link to comment Share on other sites More sharing options...
Scooby2.5 Posted February 12, 2017 Share Posted February 12, 2017 (edited) Attached for reference: STI brake booster rod spec See post 212. That is the spec for legacy Pretty sure you have to match legacy spec or you have issues because of rod length and firewall width etc. Edited February 12, 2017 by Scooby2.5 Link to comment Share on other sites More sharing options...
Th3Franz Posted February 20, 2017 Share Posted February 20, 2017 Does anyone have the length of the rod from inside the car to the base of the U fitting? I think my weak brake performance is because it's too far out. I might just have to experiment with it. -Franz The end of a Legacy http://www.youtube.com/th3franz Link to comment Share on other sites More sharing options...
haxzor Posted February 21, 2017 Share Posted February 21, 2017 The rod is supposed to be 136.3mm from the back of the brake booster so if you account for the thickness of the firewall ~8-10mm would put you in the ballpark. ------------------------------ -Mike Link to comment Share on other sites More sharing options...
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