2010 Legacy brakes upgrade

[chesnimnus]

I have a 2010 Legacy with the 2.5l NA engine and factory 17" alloy wheels.

The car has been great overall.

However, the brakes could be a little better.

On country drives or in the national forest when I get a little spirited, I get noticeable heat fade.

 

On any number of cars and trucks that I have owned over the years, I have improved the brakes by installing larger rotors and larger calipers from newer or sportier or heavier-duty models of similar vehicles.

I don't want to spend money on high-zoot aftermarket parts, but would like to install the largest stock rotors and calipers that will fit the car and the wheels.

Cursory online searches tell me that Subaru parts are pretty interchangeable, but most of what I find is geared toward the older and sportier cars.

I spent some time reviewing the online parts catalogs (Raybestos, NAPA), and below is what I see:

 

FRONT

I can replace the old 11.55" vented rotor with a 12.42" vented rotor using stock items from my local parts store.

Also, I can replace the old 1.6"-bore calipers with 1.68" bore calipers.

Both of these items are standard for the 2.5l turbo/3.6l NA vehicles.

 

 

REAR

I can replace the old 11.25" non-vented rotor with a 11.4" vented rotor for a 2.5l T/3.6l NA vehicle.

The catalogs are lacking in info on the calipers, but it appears to me that there is no difference in caliper sizes; is this true?

 

 

Do I need to replace the backing plates or caliper brackets if I change the calipers and rotors?

Are there some larger rotors and calipers from another Subaru model that I am not aware of?

Will they fit my wheels? (Visually, it appears they will with room to spare, but I would like to hear from someone else that has already done this.)

Do I need to get rotors with the ABS ring, or is that mounted on the spindle, or is that something that I will need to press out of the old rotor and into the new one?

Edited August 22, 2016 by chesnimnus

[idosubaru]

;ABS is a nonissue, it's part of the wheel bearing assembly. 

[1 Lucky Texan]

are you running good tires? what pads are you running? had the fluid flushed?

[chesnimnus]

I have to get new tires, as one went bad over the weekend.

Looking to get 235/50R17s for a slightly wider footprint and taller tire.

Apparently I need to keep the tire OD at or below 27" to maintain ABS function.

 

Pads need to be replaced, timeline of which is driving my effort to upsize.

If anyone has any recommendations on pads, I am open to suggestion.

 

Hadn't heard of flushing brake fluid in 40 years of working on cars.

Aside from removing fluid with dissolved water, what is the benefit?

Edited August 22, 2016 by chesnimnus

[1 Lucky Texan]

yeah, as it's hygroscopic, the fluid's boiling point becomes reduced.

 

there may be other additives that help keep seals happy.

 

OEM pads are great, akebono ceramic, but, many people save a little money and have no issues with name-brand aftermarket ceramic or maybe semi-metallic.

 

I like the Centric PosiQuiet Ceramic. long-lasting, noise free,similar dust and performance to stock pads, good value.

 

On my WRX that gets a little spirited driving, I run StopTech Street Performance. they are also good for the occasional track day. Good initial bite cold, modulate well, not crazy $$$ - but dusty!

Edited August 22, 2016 by 1 Lucky Texan

[idosubaru]

Okay, updated recomendations - but bear with me since this is a new topic for you and an odd situation for a Subaru - let's talk about brake fluid.   And specifically Subaru specific braking, I'm very familiar with Subaru's but nothing else. You are right to be skeptical as Subaru's generally can go 100,000+ miles without noticing any issues for most people/vehicles, so the same reason you're skeptical is the same reason we're hesitant - there's a lot of question marks here. 

 

Subarus rarely experience what you're experiencing, it's so rare I usually ignore people's self-diagnosis on Subaru brakes, though you obviously know what you're talking about.  So we have a big question mark.  bigger brakes are usually pointless (except they're fun) unless you're aggressively racing or towing high loads and grades.

 

I would check the slide pins - make sure they're properly moving and greased with high quality grease - the stuff they come with from Subaru is excellent and there should be no reason to need anything at this young of an age.  But again something doesn't seem to add up. 

 

I would also check the slide pin bushings - they can swell and cause the pads to make too much contact with the rotor - which would equal heat.  I actually throw the bushings away because they're unnecessary and were never used for decades by Subaru and they cause issues.  Usually this happens after a brake job - exposure or mixing of greases, or using cheap greases, etc swells the bushings.  Seen it multiple times and it can vary enough in symptoms that it's not really problematic or you don't even notice until you go to do a brake job. 

 

Usually braking improvement from larger brakes (particuarly with newer Subaru's) is actually zero improvement or negligible  It's a mistaken correlation.  The new calipers required new fluid and got new/cleaned pad clips and greased pins and the braking system is back to OEM new.  had they simple bought new pad clips, cleaned/greased pins with high quality grease, and flushed with new fluid they'd have the same "improvements".   modern cars only have to lock up the brakes - the weight, ABS, and tire compounds then determine braking distance/performance.  (again, outside of racing/towing)

 

 

Hadn't heard of flushing brake fluid in 40 years of working on cars.

Aside from removing fluid with dissolved water, what is the benefit?

 

 

you can even test for water in it, which might be worth it if you're noticing issues. 
http://pagid.com/news/why-test-brake-fluid/

 

I'm surprised you had brake issues but not pulsating while braking from highway speeds due to overheating compromising the rotors, a common symptom of compromised Subaru brakes.  

 

I would change your fluid first - 30k is much sooner than usually necessary but Subaru says every 30,000 miles and we dont' know any history or details about your vehicle:
 http://www.cars101.com/subaru/subaru_maintenance1.html

 

Generally speaking for average daily drivers - Subaru's make 100,000+ miles without issues on brake fluid.  So it wouldn't be normal to "need" the fluid changed but there's a lot of unknowns here: 

 

1. are you the original owner?
2.  what happened in it's first 6 years of life?
3.  miles?

4.  how "spirited" of driving are we talking?

5. how humid is the environment this car has been in?
6.  has the brake fluid cap ever been accidentally removed for an extended period of time during brake work/replacement?

7.  are the pin bushings swelling? 
8.  who changed the brakes last and what grease was used?

 

and on and on and on...

 

So it might be simple to start with two simple questions: 

 

a.  is it a good idea to just change the fluid to be sure?
b.  check the slide pin operation?