Numbchux Posted March 25, 2016 Author Share Posted March 25, 2016 When you say as the pedal travels further but takes less force to provide the same clamping force to the wheel, are you talking about the actual force to press the brake pedal? If so you are wrong it will take more force with a stock brake system to push the pedal to bring a car to a stop. I believe it will travel less overall but take more force. A lot of people have that backwards. +1 with the hill holder or abs pumps being Ts in the brake system, 1 line will go into them and two will go out. He's got it right. The way I did the math, the higher the ratio between master cylinder area to caliper piston area, the more leverage. More leverage means more pedal travel, and less force. I said it wrong when I said this: And the 1 1/16 Master is 572 square mm, that makes a ratio of 14:1. Which actually means I still have less leverage than a stock car. My point was that this Master Cylinder change was not even making up for the larger Calipers I have. But I said it backwards, I actually have more leverage, which means more pedal travel. Quote Link to comment Share on other sites More sharing options...
D3F0 Posted March 28, 2016 Share Posted March 28, 2016 (edited) I am actually going to drive my car soon for the first time in over 14 months I will post up here how it all feels. I will try with and without the upgraded bigger brake booster also. Edited March 28, 2016 by D3F0 Quote Link to comment Share on other sites More sharing options...
turbosubarubrat Posted March 28, 2016 Share Posted March 28, 2016 Just curious, could I get a legacy MC on an ea81 without changing the booster? I just put on a legacy non abs 1" master cylinder on my hatchback with the factory booster. I capped off 2 ports since it had four and i wanted to keep the hill holder. If you haven't added a proportioning valve yet i would do that too. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted January 24, 2017 Share Posted January 24, 2017 Any updates on this? Has anyone swapped a non-ABS booster/MC combo? Quote Link to comment Share on other sites More sharing options...
Numbchux Posted March 22, 2017 Author Share Posted March 22, 2017 I just stumbled on a brake bias calculator, and wanted to run the numbers on my XT6 through it, and I thought I'd post it up... Keep in mind, this does not account for brake booster or proportioning valve, so the raw numbers aren't completely accurate, but since I didn't change those parts, it makes for an interesting comparison. I'm using the default 60 lbs of pedal force, and 0.4 coefficient of friction on the pads. Stock XT6 (7/8 master, 54mm front calipers, 262 mm front rotors, 30mm rear calipers and 256 mm rear rotors): 579 psi of line pressure 176 ft/lbs of front braking torque 91 ft/lbs of rear braking torque for a 65% front bias (again, without the proportioning valve) Now I have... SVX Master 1 1/6th, 43mmx2 front calipers, 276 mm front rotors, 38mm rear calipers and 256 mm rear rotors. 451 psi of line pressure 287 ft/lbs of braking torque on the front 114 lb/lbs on the rear leaving 71.4% front bias. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted March 22, 2017 Share Posted March 22, 2017 I'd be willing to bet the stock brake bias for most Subarus of any generation is closer to 80% front /20% rear. Quote Link to comment Share on other sites More sharing options...
damnsubaru Posted June 13, 2017 Share Posted June 13, 2017 all i know is stock subaru brakes suck, in a emergency the pedal goes almost to the floor before they lock up and this is with all new brake parts, it is a design flaw , maybe it is the brake hoses that expand during panic stops like idiots stopping on the freeway because they missed their turn. 1 Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted June 13, 2017 Share Posted June 13, 2017 Damnsubaru, you need to bleed your brakes. Quote Link to comment Share on other sites More sharing options...
naru Posted June 14, 2017 Share Posted June 14, 2017 or adjust the rears or replace the master cylinder or proportioning valve (if so equipped). Definetly something wrong w/yours. Quote Link to comment Share on other sites More sharing options...
turbosubarubrat Posted June 16, 2017 Share Posted June 16, 2017 Any updates on this? Has anyone swapped a non-ABS booster/MC combo? I tried to make it work but ended up making the booster leak since i hit it one to many times to make it fit. You will have to cut a section out of your strut tower and reshape that area. Dent some of the over hanging fire wall for the spare tire or cut a piece off. The clearance to the steering shaft was in feeler gauge territory. You also have to make a bracket section from the booster to the pedal. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted June 20, 2017 Share Posted June 20, 2017 I finished swapping to the SVX master cylinder on my RX last weekend and WOW, what a difference! This car is stupid fast with the JDM WRX engine and when I got the car the brakes were terrifying. I would not let other people drive the car because you had to be looking/thinking so far down the road to have enough stopping distance. If you're converting an EA82 to an EJ or even XT6 brake system, you NEED to upgrade the master cylinder. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted March 1, 2019 Share Posted March 1, 2019 On 1/9/2016 at 6:43 PM, Numbchux said: As far as I can find, only Cardone makes a remanufactured masters for a FWD SVX. Part # 11-3849. It's either that or used (OE rebuild kits are discontinued...). Luckily those Cardone units are not terribly expensive. Just got a notification from Rock Auto that this part number has been discontinued and they do not anticipate any new stock in the future. Some quick Google-Fu shows there are still a few places around the web that list them, but who knows if they actually have anything in stock. I just bought two spares, I hope I don't get an "out of stock" bounce-back email... Quote Link to comment Share on other sites More sharing options...
Numbchux Posted March 1, 2019 Author Share Posted March 1, 2019 1 hour ago, carfreak85 said: Just got a notification from Rock Auto that this part number has been discontinued and they do not anticipate any new stock in the future. Some quick Google-Fu shows there are still a few places around the web that list them, but who knows if they actually have anything in stock. I just bought two spares, I hope I don't get an "out of stock" bounce-back email... Then you'll have to get a 2 port one and a pair of splitters. Same function, but much easier to find. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted March 1, 2019 Share Posted March 1, 2019 Meh, I've got a few of these MCs squirrelled away in the shop. Not a fan of adding two additional leak points to the brake system either, so the four-port SVX MC was the only option that works for my needs. Quote Link to comment Share on other sites More sharing options...
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