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00 BE, 92 BC, 77 celica GT
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Discussion Starter #1
Car: 99 obs, 5mt, abs

My question is.. just put 04 usdm wrx two pots up front, to replace my single pot l calipers. Try stop Fucking great when I step on the pedal, but I seem to have a soft pedal for the first half of travel, no fall off. System is bled correctly.

My question is, what direct bolt up master cylinder can I swap in to make up for extra oomph needed for the bigger brakes? and I do plan on converting the rears to disk, using the 04 usdm wrx single pots, so if we could keep in mind that I need to feed them too soon that would be great.

would the gc 2.5rs master be enough? Or the svx be ideal? I know the gc utilize a 2/1 configuration; but I can't seem to find the size difference between them and the 04's. Id like to not swap boosters, but if I have to I will.

Thankyou
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #3
Nope, not yet. Further down the line but I figured the majority of my "swell" was in the now underpowered mastered. I was going to do the bias valve when I did the rears as well, but are you now saying that only if I went with the rs master? Ill probably go with the svx master. Thanks for the link! Can cross the part number with carquest and probably get a reman on the cheap.
 

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2001 A.W. L
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13,249 Posts
yeah thats why I love that site!

I believe the L and RS master are the same diameter so I dont think an RS would be an upgrade. I believe the SVX has the largest bore, I have seen all the numbers posted somewhere but I can find the thread. I think its L/RS 15/16, wrx 1", SVX 1 1/16"

I havent upgraded the bias and as a DD it didnt bother me, as a track car now I am going to swap it out.
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #5 (Edited)
Ahhh ok, yeah with my beater down my car wont be seeing the track (parking lot) as I planned for it to; so I've got time to do so. I know what link your talking about but couldn't find the Fucking thing either lol what are your thoughts about my booster? Looks like the p/n is the same for the rs and l..
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #8
Will the sti master not work? Its 1 1/16 or 1/8 and I thought I saw that others were using it.
Probably wouldn't be a direct bolt in. Im also pretty sure the sti booster is a two stage booster as well
 

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1995 WRX 2015 F150
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1,873 Posts
The RS, WRX, STI, SVX and all the foresters and legacys with 2/1 pot are all 1 1/16". There are different 1 1/16" masters that fit different boosters and different line configurations.

There was a 1" master for a few years on the legacy with the smaller 1/1 pot discs.

All the non abs drums cars are 15/16"

I have a few RS masters with boosters in my FS threads for $20 each. If your car is abs and has a 2 port master this would work.

If you don't have abs, the 4 port non abs master is the upgrade.
 

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MAGA
'93 GF8 Track Car
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116 Posts
I'm using a '94 SVX MS on my '98L, straight bolt up affair. I suffered the same issue after upgrading to the '06 WRX calipers and this did the trick. The '94 is non abs as is my '98L.
 

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MY99 GF4 EJ227 JDM 6spd
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5,262 Posts
Impreza L non-ABS are 15/16
OBS/RS/WRX/Forester are 1"
Legacy Outback 96+ are 1 1/16"
WRX STi GDB are 1 1/16"
SVX AWD/FWD are 1 1/16" (diff parts for AWD and FWD)


The RS, WRX, STI, SVX and all the foresters and legacys with 2/1 pot are all 1 1/16". There are different 1 1/16" masters that fit different boosters and different line configurations.

There was a 1" master for a few years on the legacy with the smaller 1/1 pot discs.

All the non abs drums cars are 15/16"

I have a few RS masters with boosters in my FS threads for $20 each. If your car is abs and has a 2 port master this would work.

If you don't have abs, the 4 port non abs master is the upgrade.
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #12
I'm using a '94 SVX MS on my '98L, straight bolt up affair. I suffered the same issue after upgrading to the '06 WRX calipers and this did the trick. The '94 is non abs as is my '98L.
My 99 is abs, so a 92-97 svx with abs would be a direct bolt up correct? At least what I got from joshuas post
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #16
Got mine today new from carquest for 61$ win. Will be going on tomorrow after work.
 

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'95 Impreza 2.2L AWD/4EAT
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I did the same when I upgraded my '95 L from single-pot fronts/drum rear to 2-pot fronts and RS/WRX rear discs. Non-ABS 1-1/16" SVX MC bolted up to my stock single-stage booster, works great.
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #18
ok lets try this again. the SVX isnt even close to being right for a direct bolt up. resevoir points are different, no sleeve out to the booster, ports further apart (this part, nbd). i went with a 97 SVX master WITH ABS
 

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2001 2.5RS SRP sedan
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593 Posts
So, if you have an abs car, the svx abs master is what you need? Also, did you abs guys have any issues bleeding your system?

I'm thinking I also wanna do this swap after I get my b13 lgt brake swap completed. I'm still held up by powder coating and front pads.
 

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00 BE, 92 BC, 77 celica GT
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Discussion Starter #20
that's the impression but it is not so. Ill post a picture of the difference of the two when I get to my laptop.


Edit.. nevermind. Can upload from tapatalk now.

My 99 obs one is on the left. Svx is on the right. Sure it fits in the hole but resevoir is different, along with the cup for the booster plunged.. aagghhrrghhghhhhhh I hate my mooshy brakes.
 

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