RexSeven HalfDork
July 28, 2009 8:44 p.m.

The brakes on my 1998 Impreza L coupe need replacing soon. Someone else here had a green GC-chassis Impreza L he upgraded with 2.5RS front brakes. Are 2.5RS front rotors and calipers bolt-in affairs, or do they require any modification?

griffin729 Reader
July 28, 2009 8:57 p.m.

I don't know for certain but there may be some wheel clearance issues. Like you may need to go up to a 16" wheel. I'm fairly certain that for an RS, WRX brakes are a direct bolt in. And with Subarus being legos other than the clearance...

jwx New Reader
July 28, 2009 9:44 p.m.

Subarus are legos, so those, the WRX, or even the Mighty STi brakes are all bolt on. Just make sure that you have wheels that fit the brakes, WRX ones need at least 16s, and STis need at least 17.

RexSeven HalfDork
July 28, 2009 9:53 p.m.

Good to know about the WRX and STi brakes, but they won't fit. I have 16" rims for the summer, but 15" steelies for the winter. Does anyone know if the GC-chassis 2.5RS brakes will fit behind 15" wheels?

ddavidv SuperDork
July 29, 2009 5:57 a.m.

Clicky linky to my web site. Rex, I think you're talking about my wife's old car. I actually used Legacy brakes, which are a very simple bolt-on. Just change the calipers, brackets and rotors (and pads, obviously). The 15" wheels fit them no problem. 15's will not clear WRX brakes. Found this on NASIOC:

Some Subaru geek said: You'll have to dig around on NASIOC maybe to find out the answer to your question. The simple thing to do may be to simply search and see if 15" wheels will fit on the RS. I waded through several pages of brake posts and all I could find was what I posted above. In brief: 1998-2005 2.5RS uses 10.7" rotors up front, with two-piston calipers 2002-2005 WRX uses 11.4" rotors up front, with two-piston calipers Brackets are larger on the WRX, to accomodate the larger rotors. Pad dimensions and calipers changed slightly in mid-year 2003, so some '03s have the old style caliper/pad, some have the newer ones. I personally wonder if the change has anything at all to do with the ABS issues people were talking about in the early WRX cars....?.... All you need are the brackets and rotors. The rears: 1998-2005 2.5RS and 2002-2005 WRX uses 10.3" rear rotors, with one-piston calipers 2000-2004 Legacy used 11.3" rear rotors, with one-piston calipers These are the "H6" rears that people get. The H6 model had them, but other Legacies did too. (Which is why some people call the upgrade naming a misnomer.) For this upgrade, you also need brackets and rotor. However you'll also have to remove or bend/modify the dust/protector shield behind the rotor, or else the new, larger ones won't push on all the way. Most people just pop them off, I think. I've upgraded my fronts, but not my rears yet. Legacy777, you stated that the RS fronts are 10.9" however the brochure for my '00 RS states 10.7"
RexSeven HalfDork
July 29, 2009 5:18 p.m.

Looking at rebuilt calipers on RockAuto, I noticed the 1998 Legacy front brake calipers are the same as the 2.5RS calipers, based on the item numbers. Works for me.

Thanks for the link ddavidv, your wife's "2.2RS" was the car I was thinking of.

ddavidv SuperDork
July 30, 2009 5:05 a.m.

I may be wrong on this, but I think early 2.5RS calipers may have been different than later ones. At some point didn't the RS go to twin pistons?

sachilles Reader
July 30, 2009 7:54 a.m.

In reply to ddavidv:

They actually use the same caliper as the early wrx. The only difference is the pad carrier. Yes the rs brakes will fit under 15 inch steelies. They both have two pistons. Later wrx's went to the 4 pot setup.

<-----has a 2000 2.5 rs and 02 wrx.

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