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An FYI for anyone wanting a master cylinder brace. While Perrin only shows that it is compatible with the 08-14 WRX/STi, I can confirm it does fit on my 2015 STi. All the holes line up and everything bolts in properly. However, you will need a longer bolt (M12x1.75) about 3" longer than the bolt that comes with the kit. Other than that everything fits perfect. I am not sure whether or not the master cylinder just sits farther back inside the car or is shorter in itself. i did not get that far.

Perrin Master Cylinder brace found here: Master Cylinder Brace for 2008-14 STI



 

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Any brace on the market will make a significant noticeable improvement. The pedal feel is more linear after I installed my cusco brace.
 

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Re: Re: Perrin Master Cylinder Brace

How was the install? Daily easy, or was it a bitch to do? Do you notice any difference?
Took me about an hour and a half by myself with going to the store in between. I wouldn't say a bitch, but definitely difficult. Just a lot of stuff in your way. Yes there is a big difference in braking. The pedal feels more firm and the braking comes on quicker. Overall I think it's well worth the money. I got mine from a buddy that parted out his 14, so I got it a little cheaper, but I would've bought one new.
 

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nope, just the bolt. i'd be wary about something in between them, might introduce flex. and the whole point of this brace is to eliminate flex :)

another point, is that the bolt is not perfectly lined up with the brace, so it hits it at an angle. putting something on the end of the bolt like the cusco brace would probably break off, due to the pre-load/you pressing on the brake pedal.
 

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nope, just the bolt. i'd be wary about something in between them, might introduce flex. and the whole point of this brace is to eliminate flex :)

another point, is that the bolt is not perfectly lined up with the brace, so it hits it at an angle. putting something on the end of the bolt like the cusco brace would probably break off, due to the pre-load/you pressing on the brake pedal.
the cusco brace (like what i have) includes an aluminum pivot disc. This distributes the force to the entire end of the cylinder, instead on concentrating it to one point. There is no additional induced flex with the pivot disc, as it is made of aluminum. The adjustment bolt is also much shorter with this unit. Id be more wary of the longer bolt of the perrin. With the length added to the small contact point, its more prone to "walk" and flex off its contact point.
 

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In theory, yes, it could walk, however, the pre-load applied to the bolt, along with my choice of a 316 SS bolt, should mitigate those issues.

In the end, if I didn't have a trackday fast approaching, I might have waited for a revised perrin design since i prefer their implementation that has triangulation of the brace itself. I personally am not confident in the Cusco design, as its just a right angle design, instead of a full triangulation. Depends on the strength of the wall of sheet metal of the strut mount. Which is an unknown since we don't have Subaru's CAD data.
 

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Just installed the Perrin triangular design. Install was definitely difficult. Instructions have you working from the top, save yourself plenty of cursing and use ramps. Much easier to do the whole install from the bottom of the engine bay.
 

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Just installed the Perrin triangular design. Install was definitely difficult. Instructions have you working from the top, save yourself plenty of cursing and use ramps. Much easier to do the whole install from the bottom of the engine bay.

thanks for the heads up. will be getting one done next spring
 

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Am I the only one who thinks the brakes are great. I dont feel any flex maybe I an not using my brakes properly. Here is my technique push far Right pedal as hard and far down as possible. On rare occasion when road is not straight lightly touch middle pedal like it's a bed of nails on your bare foot. Pray you make the corner so your right foot can get back to work. Please help.
 

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Am I the only one who thinks the brakes are great. I dont feel any flex maybe I an not using my brakes properly. Here is my technique push far Right pedal as hard and far down as possible. On rare occasion when road is not straight lightly touch middle pedal like it's a bed of nails on your bare foot. Pray you make the corner so your right foot can get back to work. Please help.

For daily driving they are great. It's when pushing hard on the track where the firewall flex will show up a bit.
 

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I didn't want to start a new thread for this, but mods please let me know if I should.

Is it a safety issue not having the master cylinder brace? With all this talk about firewall flex without the brace, I'm curious if a serious problem will show up on track.

Also, how does it work? Is the master cylinder moving around when I press the brakes hard and this brace is just securing it to somewhere else on the unibody?

Reading through these responses and many others in similar threads, I'm already convinced that this will instill more confidence in braking, but I'm just curious about the details of the issue. I like knowing the why haha
 

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I didn't want to start a new thread for this, but mods please let me know if I should.

Is it a safety issue not having the master cylinder brace? With all this talk about firewall flex without the brace, I'm curious if a serious problem will show up on track.

Also, how does it work? Is the master cylinder moving around when I press the brakes hard and this brace is just securing it to somewhere else on the unibody?

Reading through these responses and many others in similar threads, I'm already convinced that this will instill more confidence in braking, but I'm just curious about the details of the issue. I like knowing the why haha
When you push down hard on the pedal the firewall literally flexes outward and pushes the master cylinder forward. You'd get a much more solid feel if this didn't happen. The brace basically mounts to the strut tower or another place that won't move and puts a stopper (bolt, usually) to stop it from moving forward. Simple design and execution but effective.
 

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I didn't want to start a new thread for this, but mods please let me know if I should.

Is it a safety issue not having the master cylinder brace? With all this talk about firewall flex without the brace, I'm curious if a serious problem will show up on track.

Also, how does it work? Is the master cylinder moving around when I press the brakes hard and this brace is just securing it to somewhere else on the unibody?

Reading through these responses and many others in similar threads, I'm already convinced that this will instill more confidence in braking, but I'm just curious about the details of the issue. I like knowing the why haha


You will be fine at the track without it. It won't break. There is just a little flex there under hard braking and the brace firms it up. That along wth stainless steel brake lines. Both help with pedal feel


Sent from my iPad using Tapatalk
 

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When you push down hard on the pedal the firewall literally flexes outward and pushes the master cylinder forward. You'd get a much more solid feel if this didn't happen. The brace basically mounts to the strut tower or another place that won't move and puts a stopper (bolt, usually) to stop it from moving forward. Simple design and execution but effective.
You will be fine at the track without it. It won't break. There is just a little flex there under hard braking and the brace firms it up. That along wth stainless steel brake lines. Both help with pedal feel


Sent from my iPad using Tapatalk
Thanks to both of you for the info.

With regard to stainless lines, is there a shorter service interval with those? Having trouble separating forum fear from facts about stainless lines being more prone to failure than OEM.
 
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