Welcome to the North American Subaru Impreza Owners Club Friday July 11, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Click here to visit TireRack
Brakes & Suspension Forum sponsored by The Tire Rack

Losing traction? Need new tires?
Click here to visit the NASIOC Upgrade Garage...
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Brakes, Steering & Suspension

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 12-08-2006, 05:37 PM   #1
stoney98
Scooby Specialist
 
Member#: 65888
Join Date: Jul 2004
Chapter/Region: RMIC
Location: Denver, CO
Vehicle:
2010 FXT

Default Upgrading Rear Brankes '03 TS - Drum to Disc

I searched but couldn't find anything related to upgrading the stock rear drum brakes on the 2003 TS to disc, even in the stickies. I have read all the braking stickies thoruoughly, but I still have noob questions so forgive my ignorance. I do understand most wrench talk, but I apologize if I ask for more info on commonly known iinfo.

I am looking at upgrading my rear drums to a set of stock WRX 2-piston discs. When I do make the change, I will be doing the fronts, upgrading to SS braided lines f/r, and most likely running Stoptech high friction street pads f/r. This car is my daily driver, but I am slowly working my way into AutoX, so I have a longterm goal of improved handling and braking. Additional power is on the list, but only after I have the car setup handling and brake-wise and my skill levels are at a level to be able to appropriately drive with additional power.

I am currently running 16" Stock WRX wheels, and I have already upgraded my rubber to ContiExtreme Contact, so I will not be doing any changes to the wheels. The conti's, new rotors [same as stock] and stoptech pads for my 2-pots were just installed with dramatic effect, but I am now starting to notice a more 'mushy' feeling from the brakes that I want to correct. I'm assuming the switch to rear disc will improve both feel and performance notably.

I have lots of questions so please be nice, I assume answers to these questions will lead to more questions. Thank you in advance.

1. Will my current 2-pot fronts fit on the rear with adapters, or are fronts and rear incompatible?
2. Since I am most likely going to upgrade to stock WRX 2-pots in the rear with slotted rotors. What am I going to need?
So far I note: WRX caliper, Slotted rotor, SS brakelines, new fluid (any particular reccomendations?), and new pads.
3. I have access to a power bleeder, as well as most of the necessary tools, those I do not have I will acquire. Any notes to what tools will make it easier to do the job properly would be greatly appreciated as well. I do have and use a torque wrench.
4. I saw the notes on diagonal vs f-r bleeding and will bleed the brakes accoringly (diagonal).

As mentioned, I will also be doing my fronts, but I am still deciding which way to go, as I currently have the stock 2-pots. I am looking for both better feel and performance, so I need to research more as to what brakes provide both without breaking the bank. Any suggestions are welcome.
One question I have regarding the WRX front 4-pots, is do they have a greater braking contact than the TS 2 pots? I saw in one of the stickies that some subie 2-pots have the same braking power and some subie 4-pots.

Thanks in advance!
-Mark
* Registered users of the site do not see these ads.
stoney98 is offline   Reply With Quote
Old 12-09-2006, 02:58 AM   #2
ten80
Scooby Specialist
 
Member#: 53625
Join Date: Jan 2004
Location: WA
Vehicle:
00 EJ205 LGT LTD

Default

I have the exact same car and did the conversion two years ago. To answer your questions:

1. no, front rotors will not fit in the rear because the rear rotors have a deeper hat to accomodate the parking brake. nor will front calipers fit on the rear because the brake caliper bracket mounting holes are way closer together in the rear.

2. You need disc rear hubs! Converting drum hubs to disc requires 80% of the parts off a disc hub, plus pressing out the wheel bearings. bad idea. Make sure you find hubs with parking brake cables installed, since its a PITA to swap them from the drum to disc hubs. To recap, you need: calipers, pads, caliper brackets, rotors, hubs, e-brake cables, wrx brake lines.

3. powerbleeder is not necessary. You can bleed by pumping the brake pedal since you are only introducing air into the very end of the system (brake caliper and line) and not the master cylinder. 2-3 brake beeds will flush all the air out.

4. yes, the diagonal method is preferred

lastly, if you want a cheap and effective front brake upgrade, get some 03+ wrx caliper brackets and 11.4" rotors. These will give you a nice power boost from the stock 10.7" rotors and the cost will be very reasonable. Subaru 4-pots do have a larger pad contact surface, however, it is debatable whether or not they have more power since they are driven by the same master cylinder. It is certain that they have less fade since there is more piston surface area to absorb and dissipate heat.

oh, I should mention that you can search for "disc conversion" and you'll find some threads of interest. the drum to disc conversion is the same for all years of imprezas.
ten80 is offline   Reply With Quote
Old 12-09-2006, 10:00 PM   #3
stoney98
Scooby Specialist
 
Member#: 65888
Join Date: Jul 2004
Chapter/Region: RMIC
Location: Denver, CO
Vehicle:
2010 FXT

Default

thank you VERY much!
stoney98 is offline   Reply With Quote
Old 01-26-2008, 09:24 PM   #4
mattbesquare
Scooby Newbie
 
Member#: 169360
Join Date: Jan 2008
Thumbs up Thank you..I am starting to get an idea of what I am in for

But I have an 08, so I am going to have to wait for a few wrecks on ebay to get the rear hubs.

ALL 2008+'s! Get the premium upgrade! it will be cheaper in the long run!
mattbesquare is offline   Reply With Quote
Old 06-11-2009, 09:20 PM   #5
skiley22
Scooby Newbie
 
Member#: 188750
Join Date: Sep 2008
Chapter/Region: NESIC
Location: Bethel, CT
Vehicle:
2008 Impreza 2.5i
Lightning Red

Default

https://www.trademotion.com/partloca...28&catalogID=2

Your welcome haha

I'll be doing this upgrade...soon enough.

I also agree with getting the premium upgrade..it is worth it.
skiley22 is offline   Reply With Quote
Old 06-11-2009, 09:47 PM   #6
bcware
Scooby Newbie
 
Member#: 190724
Join Date: Oct 2008
Chapter/Region: NESIC
Location: NH
Vehicle:
2008 2.5i Sedan
Lightning Red

Default

increasing gain will improve pedal feel. increasing/decreasing brake system gain can be achieved several ways:

for more gain...

increase brake pedal ratio
increase brake booster gain
decrease master cylinder piston diameter
increase caliper piston diameter
increase brake pad coefficient of friction
increase rotor effective radius
decrease tire rolling radius

reducing compliance can also improve pedal feel. stainless steel hoses reduce compliance and improve pedal feel.

motul rbf 600 brake fluid, or any other major brand name you trust that has a high dry/wet boiling point fluid. look for a dry boiling point of around 600 and a wet boiling point of around 500 degrees F. do NOT use a DOT 5 brake fluid which contains silicone... never use old or opened brake fluid. always use a new, sealed container as the fluid rapidly becomes "wet" over time once opened.

size and shape of brake pad do not contribute to gain because a brake pad material's coefficient of friction is independent of the size of the brake pad itself. however, a larger pad will have a longer life span and provide more thermal mass to absorb heat.

switching from drum to disc will improve pedal feel, dramatically increase thermal mass, and increase cooling (drums are closed and don't cool well via convection).

um, that's all i can think of off hand.
bcware is offline   Reply With Quote
Old 10-29-2010, 05:53 PM   #7
04wrexsti
Scooby Specialist
 
Member#: 225937
Join Date: Oct 2009
Chapter/Region: Tri-State
Location: North Jersey
Vehicle:
'10 SE STI '04 FXT
'00 RS race car

Default

im planning on building a 02 2.5ts wagon rally car, it would be nice to get rid of the rear drums and swap for disks because well brakes are very important in rallying

so basically you need the rear hubs and everything of a car with disks in the rear? does it matter if they are from a sedan, wagon, bugeye, hawkeye, etc ?you get what im talking about.
04wrexsti is offline   Reply With Quote
Old 10-29-2010, 07:24 PM   #8
feint05
Scooby Specialist
 
Member#: 152984
Join Date: Jul 2007
Chapter/Region: SCIC
Location: san diego
Vehicle:
2004 jewbaru
jewbuilt, polish tuned

Default

Quote:
Originally Posted by ten80 View Post
I have the exact same car and did the conversion two years ago. To answer your questions:

1. no, front rotors will not fit in the rear because the rear rotors have a deeper hat to accomodate the parking brake. nor will front calipers fit on the rear because the brake caliper bracket mounting holes are way closer together in the rear.

2. You need disc rear hubs! Converting drum hubs to disc requires 80% of the parts off a disc hub, plus pressing out the wheel bearings. bad idea. Make sure you find hubs with parking brake cables installed, since its a PITA to swap them from the drum to disc hubs. To recap, you need: calipers, pads, caliper brackets, rotors, hubs, e-brake cables, wrx brake lines.

3. powerbleeder is not necessary. You can bleed by pumping the brake pedal since you are only introducing air into the very end of the system (brake caliper and line) and not the master cylinder. 2-3 brake beeds will flush all the air out.

4. yes, the diagonal method is preferred

lastly, if you want a cheap and effective front brake upgrade, get some 03+ wrx caliper brackets and 11.4" rotors. These will give you a nice power boost from the stock 10.7" rotors and the cost will be very reasonable. Subaru 4-pots do have a larger pad contact surface, however, it is debatable whether or not they have more power since they are driven by the same master cylinder. It is certain that they have less fade since there is more piston surface area to absorb and dissipate heat.

oh, I should mention that you can search for "disc conversion" and you'll find some threads of interest. the drum to disc conversion is the same for all years of imprezas.
high five good stuff
feint05 is offline   Reply With Quote
Old 12-01-2010, 11:53 AM   #9
tethy
Scooby Newbie
 
Member#: 262794
Join Date: Nov 2010
Default

Would the same apply to a drum to disc conversion on a 98 L sedan?? The new hubs and cables are my main concern. I so want to ditch the drums.....
tethy is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone doing rear drum to disc upgrade soon? p2adan North West Impreza Club Forum -- NWIC 15 06-17-2009 03:20 AM
Drums to Discs in an 02 TS Falkonite Interior & Exterior Modification 1 10-06-2008 11:28 PM
$325; Rear drum to Disc JDM VENTED 10.5" disc brake for WRX or GC8 complete KIT supermoose Private 'For Sale' Classifieds 10 02-25-2006 01:50 PM
2002 OS rear drum to disc upgrade IAmNoChode2 Brakes, Steering & Suspension 0 05-13-2002 04:49 PM
Upgrade 02 outback brakes from drum to disc? Marty S Brakes, Steering & Suspension 2 10-21-2001 04:26 PM


All times are GMT -4. The time now is 07:28 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.