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Brake swap, 99 impreza OB front disk 1 piston to 2 piston

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The dual piston does use a larger brake rotor, so you will have to swap the caliper bracket with the rotor to clear. You will require 15" wheels to clear.


Although it may be possible to just swap on the caliper itself onto the existing bracket. I guess that is the answer you are looking for, but i am only speculating.

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It is not possible to do it without brackets, rotors, calipers and pads. Having done six or seven of these swaps in the last couple years I can verify it first hand.

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I did this to my 94 legacy wagon. They came form an 00 legacy outback. From what i understand, 90-94 turbo legacy, and impreza rs are the sme as well as 2.5 equipped soobs

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I did this to my 94 legacy wagon. They came form an 00 legacy outback. From what i understand, 90-94 turbo legacy, and impreza rs are the sme as well as 2.5 equipped soobs


They are equivalent. The turbo legacy caliper brackets are slightly different, and require different pads (which are unique to the t-leg, drastically limiting your pad options).




I love the 276mm 2-piston setup. I've used it on several cars, and with good pads, it's as much brake as you'd ever want for street use.


Although, the 292mm 2-piston is pretty sweet. We've got an 03 Outback with those (stock) and they're pretty nice. And with a little work with a grinder on the calipers, I was able to get 15" wheels to fit.

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I put the duel piston calipers and rotors from 98 outback on my 97 impreza worked great no problems and stops way faster and added a 2nd E brake lever for better offroad turns Liken the rear drums with twin ebrakes

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The other day i tried to fit 03 outback rotors to a 98 forester. although they both appear to use the same caliper, the forester rotor was smaller. I would imagine the forester, 98's and older, have similar dimension to the turbo legacy of first gen, and the 00 and up has the larger rotors with rs, wrx, and 2.5 subarus

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The other day i tried to fit 03 outback rotors to a 98 forester. although they both appear to use the same caliper, the forester rotor was smaller. I would imagine the forester, 98's and older, have similar dimension to the turbo legacy of first gen, and the 00 and up has the larger rotors with rs, wrx, and 2.5 subarus


There are a couple different sizes. 276mm and 294mm. The 276s are crazy common, T-legs, anything 2.5 non-turbo until 2002, and more. 294s are WRXs, 03+ Outbacks, and others. (There's an old post in the USRM with the exact model list). These do, in fact, use the identical calipers, but different brackets to accomodate the different rotor sizes.

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Wall of text incomming:

To start, you can put almost any set of Subaru brakes on any other Subaru. If you want WRX brakes on your L or something you pretty much just have to buy some and bolt them on. There are some exceptions, however, mostly relating to the rear, which are explained later on. And also in this thread

Additionally, the 05+ sti has a different bolt pattern (5x114.3 vs 5x100) so those rotors are not compatible with other models.

If your car has rear drum brakes, a disc swap is fairly more involved. I'm not entirely sure on the process but there are more details farther down.

I would also be wary about trying to exchange stuff with the 08s. The rear backing plate is completely different so to the best of my knowledge nothing is interchangeable.

So, if you're wondering what brakes you have and what other brakes are out there, I've made this big list of most of the different brakes found on modern Subarus. The information came from a lot of places like the DBA catalog (click the rotor size for spec sheets provided by DBAsteve), cars101, and various threads/FAQs here and on scoobymods. This is mostly just about US model cars. Generally brakes were the same around the world but there are a few little special exceptions that are linked to later on.

Disclaimer: While I have tried to make this post as accurate as possible, there are some mid year revisions. I also can't be positive all the year ranges listed are correct, especially for pad shapes. In some cases, it is necessary to call a dealership with your VIN number or physically compare parts.

Front Brakes

Smallest Subaru front brakes, found on FWD non-abs Imprezas (93-96). The caliper and bracket are similar to those for early 260mm brakes with a shorter bracket and they use the same pads. These things fit under 13" wheels.
93-96 Impreza 2WD.

This is the most common front rotor size before 2000. It was found on many Imprezas and Legacies and uses a single piston caliper and bracket. Somewhere around 96/97 the caliper/bracket/pad design changed. These fit under 14" wheels.
90-99 Legacy non-turbo/-GT/-Outback
1995 Outback
93-01 Impreza AWD (non RS)

This uses a two piston sliding front caliper and there are three caliper/bracket designs. One for the 91-94 Legacy SS/TW, an early Legacy 2.5GT/Impreza RS bracket (~96-99), and a Later RS/GT bracket (03+). It's possible to exchange some of these calipers onto taller WRX brackets as long as the pad shapes match.
91-94 Legacy turbo
96-01 Legacy GT
96-01 Outback
00-04 Legacy non-GT
98+ Impreza RS/TS/2.5i
98+ Forester
Some non-us BRZ/FRS/86 models.

This is the WRX front rotor. It uses a two piston sliding front caliper or the Subaru fixed 4-pot. The sliding caliper, bracket, and pad were changed in 03 and that's something you need to be aware of when upgrading from RS brakes or purchasing pads. The 4-pots are only on the 06-07 WRX in the US, though they were on many older non-US STis and WRXes (the black calipers with Subaru across them). Generally 16" wheels are required with these brakes but there are some 15" wheels out there that work. Also 16x6.5 Subaru wheels do not clear 4-pots.
01 Legacy GT LTD?
02-04 Legacy GT
05-09 Legacy non-gt *
01-09 Outback
02+ Impreza WRX (including 08, which uses 2-pots)
03+ Forester

Here is the description on the different DBA rotors in this size:

Originally Posted by WRXBrakes viewpost.gif

DBA 1 piece:

Standard series - p/n 650 - fits 2 or 4 piston WRX w/294mm rotor

4000 series - p/n 4650 - Again fits all 2 or 4 piston 'WRX' applications. However - some street pads w/ shims on them may not fit w/ the shim as the rotor is intentionally a bit thicker to add heat mass. Take shims off - run a few weeks - if it gets noisy wait till they can fit.

p/n 4000 - Original 4000 series rotor w/ tapered HAT section to clear OUTBOARD ABS tone ring. This ABS system is all pre-2000 MY afaik.

5000 series:

p/n 5000 -the OG - fits 4 pot WRX (pre-USDM 2 pot)

p/n 5010 - fits 2 pot OR 4 pot front WRX calipers. This rotor was made when it was realized that the caliper bracket from the USDM WRX hit the rotor hardware on p/n 5000. Thus 5010 has a different design- the hardware is recessed for clearance.

Added bonus points: This rotor is also available in 5x114.3 to make it possible to swap an 05-07 STi to the subaru 4-pots for rally. Not sure where to find that rotor but I would start with rally shops. A standard WRX rotor cannot be re-drilled to 5x114 as it won't fit over the larger hub.

*The non-turbo Legacy actually has a slightly different rotor that is technically 292mm in diameter. It is also slightly heavier than the WRX rotor. They can be interchanged without issue.

This uses a two piston sliding caliper similar to the other 2-pots, although brackets and calipers aren't compatible between other 2-pots. 17s are required with them.
05-09 Legacy GT
Tribeca (5x114.3 bolt pattern)

326x30mm (5x100)
326x30mm (5x114.3)
STi rotor that goes with the 4-piston Brembo calipers. There are two rotors, the 04 has a 5x100mm hub bolt pattern, 05+ uses 5x114.3. The calipers all mount the same way so you can attach front Brembos to other Subarus without trouble. There were some changes to the caliper over the years that involved some sort of stiffening, so from what I can tell an 07 caliper would be slightly better than an 04.
04+ STi

A note about the SVX:
The SVX has brakes that are about the same size as WRX brakes and the SVX has 5x114.3 hubs. However, up front, the rotor hat offset (how close or far the rotor surface is from the hub) is different from that on other Subarus. The knuckle also locates the caliper bracket in a different position. That unfortunately means that you can't just buy some 05-07 STi brembos or Tribeca brakes or something to upgrade your SVX. I'm pretty sure that in the rear things are compatible with other Subarus.

Rear Brakes

The most common Subaru rear rotor. It uses a single piston sliding caliper, of which there are a few variations. Early Legacy sedans (non-turbo) and Imprezas have a smaller piston than Legacy wagons and turbos, and there are a few bracket/caliper revisions.
90-99 Legacies/Outbacks with rear discs non-turbo
93-07 Imprezas with rear discs (except sti, 06-07 wrx)
98-08 Foresters with rear discs

This rotor is on most 05-09 Legacy/Outbacks. The exception is the LGT and probably the 3.0R. Parking brake is 170mm. Seems to be only be on these models.

2008+ impreza/wrx
2009+ forester (with rear discs)
2010+ Legacy 2.5i
Some non-US BRZ/FRS/GT86 models
uses a 190mm parking brake and 1-pot sliding calipers.

This is well known as the H6 rear rotor. The Legacy caliper is the same as most other 99-07 1-pot Subaru calipers so you can upsize to this rotor simply by purchasing the brackets and correct pads.
The "H6" bracket is part number 26625AE000. It uses pad shape D770
00-04 Legacy/Outback non-brighton
SVX (5x114.3, 190mm parking brake)
Ver5 STI type-RA (5x100, 190mm parking brake)

This is the Legacy turbo rear rotor. The caliper is similar to the other calipers but is wider to accomodate the vented rotors. I hear it was also found on the v1 WRX (93-94).
91-94 Legacy turbo

290x18mm (170mm parking brake)
290x18mm (190mm parking brake)
290x18mm (2010+ Legacy GT, BRZ)
There are actually three different rotors in this size. The first is the standard 06-07 WRX and 05-09 LGT rotor. It uses either a 2-piston opposed caliper or a 1-pot slider. The 2-pot will not bolt up to other Subarus without something like the Kartboy brackets or having a new backing plate pressed onto the spindle. The next version is for the STi 190mm parking brake so that 2-pots can be used on rally cars. The third version is for the newer cars. It can be found on the 2010+ LGT and the BRZ/FT86/FRS. This third version could also be used as an upgrade for the 08+ Impreza if you wanted to go to slightly larger vented rotor. It does not interchange with the group n rotor.
05-09 Legacy GT (1-pot, 170mm park brake)
06-07 WRX (2-pot)
04-07 STi with FHI 2-pot conversion
2010+ Legacy GT

Some older non-us spec-b Legacys and wrx/sti models (see rear brake redux)

Note: The LGT uses a different brake line than older Legacies and Imprezas. So I think you need to grind down part of the caliper where the line mounts to get it to work on an Impreza. The LGT lines are a different shape and mount and a different angle and you can't use them.

316x20mm (5x100)
316x20mm (5x100, 170mm parking brake)
316x20mm (5x114)
STi brembos. There are multiple versions of this disc. One for the 04 STi, one for 05-07, one for 08+ and one with a 170mm parking brake drum. There's an explanation how to install rear brembos on other cars a little farther down. 08+ sti rear rotors have a different backspacing.
04+ STi

Hey that's an odd size now isn't it. I was previously wrong with my thinking the Tribeca uses the same rotor as an STi. It does have the same bolt pattern (5x114.3) though. AFAIK, it uses a 170mm parking brake but don't quote me on that.

So, what does that mean? The calipers and brackets should work on an SVX. Unfortunately no front brakes are interchangeable onto an SVX because of the rotor hat back-spacing.

Some cars have rear drums that are like 9." I don't really know anything about Subaru drum brakes so it would help if someone filled that stuff in.
Some of them are: Legacy and Impreza Brighton models, Some 95-99 Legacy L models, some foresters and I think 02+ Impreza TS and OBS. (I'm not sure exactly)

To swap out drums, at the least you will need new parking brakes, backing plates, discs, calipers, and brake lines. It is usually best to get a whole knuckle/hub/parking brake assembly out of a car with rear discs. If you want to put rear discs on your front wheel drive Subaru, you might have to parts from a 90-94 Legacy, since they might be the only FWD Subarus with rear discs and the FWD rear hubs/spindles/struts/etc are different.

Installing rear Subaru 2-pots or Brembos on a non 2-pot car:

The Subaru and Brembos have the same backing plate, which is different from all the other Subaru rear disc backing plates. So calipers don't swap between the two. Additionally, the STi uses a 190mm parking brake drum. Pretty much everything else uses a smaller 170mm drum. That means if you take a set of rear brembos and put them on your WRX, the parking brake will not work.

However, there are Subaru 2-pot rotors (290x18mm) with a 190mm parking brake hat and Brembo rotors (316x20) w/ a 170mm e-brake so you can put either setup on either car. There are also Kartboy brackets that will adapt the 2-pot calipers to any other Subaru, and since both rotors are available in 170mm parking brake variety, you can swap either one onto any other Subaru. Here's a thread about fitting the brembos to other cars with the new Kartboy brackets and DBA rotors.

Here is the rear brake redux, which has more information about the older rear brakes that came on STis and fancy Legacys in Japan.

Some D-plate numbers
Originally Posted by stoptech
The Friction Materials Standards Institute (FMSI) is an association that assigns numbers to different pad shapes that are used as a guideline for pad manufacturers to refer to, and bring a common numbering system to the brake pad aftermarket. Virtually every pad manufacturer will either use the FMSI number in their numbering system or have a readily available interchange to cross-reference their part number to the FMSI number.
I should note that the caliper bracket, and not the caliper, is what determines pad shape. So while there are a few different pads, in some cases the calipers are the same.

Front 1-pots

1990-1995 Legacy
1993-1996 Impreza

1996-1999 Legacy
1997-2001 Impreza

Front 2-pots

1991-1994 Legacy Turbo
1996 Outback
1996 Legacy GT

1997-2002 Legacy
1998-2001 Impreza RS
2002 Impreza and WRX
1998-2002 Forester

2002-2009 Legacy/Outback (non-gt)
2003+ Impreza/Forester
8/2002-2005 WRX
2008+ WRX

I added a new shape, 1539. It is listed specifically for the 11+ but the basic shape is still the same. Difference is that the new pad has more friction material on it and slightly different wear indicators.

See this article for clarification on 02-03 shapes

2005-2009 Legacy GT

Rear 1-pots

1990-1999 Legacy
1993-1998 Impreza
1993-1997 SVX

2000-2004 Legacy
2005-2009 Legacy GT
1999-2002 Impreza

11/2002-2005 WRX
2003-2007 Impreza

2005+ Legacy 2.5i/Outback (incl 2010+)
2008-2011 Impreza
2008-2012 WRX
2009+ Forester
non-vented FRS/BRZ/86 rear brakes

2010+ Legacy GT

FHI 4/2-pots
Front: D647 (or D1170, D460, D1182)
Rear: D461

STi Brembos
Front: D1001
Rear: D961

Missing information:
- non-us market vehicles
- 2012 Impreza
- BRZ (but I'm pretty sure the rear brakes are the same as the 08+ WRX)




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