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2018 - Brakes - part numbers?

1278 Views 24 Replies 9 Participants Last post by  TTiimm
Hi guys, does anyone know the part number for brake rotors and brake pads for 2018 Forester XT with 18" wheel? I checked around, they are mostly for 16" and 17" wheels. And does anyone have experience with aftermarket brands for Forester's brakes? Which one is good and doesn't need modification (perfectly fit)?
My car is just 55K kms and I measured with the coloured gauge, the rears are less than the thinnest red, and the fronts are exactly the thinnest red.
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The size of the brake pads and rotors are determined by the engineers to provide optimum balanced braking. You don't need bigger rotors, pads, and calipers for 18'' wheels.
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The size of the brake pads and rotors are determined by the engineers to provide optimum balanced braking. You don't need bigger rotors, pads, and calipers for 18'' wheels.
… thats why he’s looking for the parts that match his car. Good lord.

Its been a long minute since I did a brake job. But got some Bosch quietstop? Something like that. Did real well. Had all the nice replacement guides and grease. Was a great kit.
Iirc the part number for the XT uses Akebono which are excellent. Just enter your vin number in the parts search for any dealership.
These are the parts I used for my most recent brake job.

DBA 4000 T3 Front Rotors: Part Number DBA42650S-10​
StopTech Sport Slotted Rear Rotors: Part Number 126.47035SL (left), 126.47035SR (right)​
EBC Red Stuff Brake Pads: Part Number DP31583C (front), DP31758C (rear)​
Napa Hardware Kit: UP 83806A (front), UP 83562A (rear)​
Goodridge Stainless Steel Brake Line Kit: Part Number 24230​
Motul RBF600 Brake Fluid: Part Number 100949​

The job was characterized (by me) as an "Upgrade" because these are premium parts, better than stock. In particular, the rotors are high-carbon steel to help with heat management.

A writeup of the brake job with photos is at ('14-'18) - TTiimm's 2015 Forester XT Touring

Really, any auto parts store, supplier website or repair shop should be able to recommend parts that fit.
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… thats why he’s looking for the parts that match his car. Good lord.
I will assume you just don't understand what I wrote. He can easily look up the parts online. The XT brakes are different but there is no special setup for 18'' wheels.
I see the 18" wheels but I only see the 16" & 17" brakes. Are you sure the 18" wheels don't use the 17" brakes?
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Thanks for the replies, guys. So the standard wheel is 18", and I'm not sure if the rotors for 17" wheels are the same size (emailed the store in US, but no reply). I asked the dealer in Vancouver, quoted $900+ for the parts, and $350 for the job, before taxes. Bleeding is another $150. So decided to diy (OEM parts from US are C$500+ after taxes, but 17" wheel, and ATE blue brake fluid is C$35).
I'm also ok with non-subaru parts, just want to make sure the parts fit perfectly, because my diy skill is kindergarten, so don't expect any hiccup in the middle.
Wheel size does not determine which rotors go on the car.

There are two types of rotors for 2018 Foresters. There are rotors for an XT and rotors for non-XT cars.

Front rotors for an XT are 316 mm diameter x 30 mm thick. Rear rotors are 278 mm diameter x 18 mm thick. Both front and rear rotors are vented.

Rotors for a non-XT are smaller and I believe the rear rotor is solid, not vented.

You need rotors for a Forester XT.
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Hi guys, anybody had experience with Powerstop? Thanks to TTiimm for providing the specs, it looks like Powerstop K6931 will fit my car perfectly. How is Powerstop compared to Subaru OEM brakes?
I believe Powerstop is a respected brand but have no experience directly. Others can chime in.

Is K6931 the kit with slotted/drilled rotors and carbon/ceramic pads?

I'll express my opinion about drilled rotors.

IMO, Drilled rotors are one of the last things to consider, after everything else has been done including fully flushing the system with high-boiling point fluid, use of high carbon steel rotors and the best pads you can find, braided stainless hoses, replace all hardware kits and hyper-anal meticulous cleaning and assembly of all parts.

Rotors are drilled to increase surface area and thereby increase cooling. The downside is that it also reduces mass and therefor, the amount of heat a rotor is able to absorb. More mass = ability to stop harder and stop more often before the brakes fade. Keep in mind that race cars have massive rotors to begin with and so drilling still leaves a lot of mass. Race cars also have cooling ducts which direct fresh air to the brakes. I think for most street cars with small-ish rotors and no cooling ducts, drilling probably reduces performance. I've no numbers to prove this but that is what I suspect.

Drilled rotors sometimes experience cracking around the holes. I don't know if manufacturers have fixed this since I first read about it but it is a concern of mine. As an example, Porsche doesn't drill their rotors but casts their blanks with holes. The holes are then finished with the rotor surface. This is done to prevent cracking but it raises cost. Porsche rotors can be $1500 each.

Everyone is free to do what they want and drilled rotors look killer. I however, would focus on
1) flush with good quality, high-boiling point fluid such as Motul RBF 600 or ATE 200
2) Use high-carbon steel rotors. "High Carbon" is a grade of steel. Call or email the manufacturer and ask what their rotors are made of. If they say "Gray iron" or some other grade then it isn't high carbon.
3) New hardware kits and meticulous assembly. Don't forget to scrub the rust off the hub to rotor mating surface with a wire brush.

Consider using a slotted rotor if you are using an aggressive pad. I don't consider ceramic to be aggressive. Slotting helps to move dust and gasses away from the friction surface and removes negligible mass. I'd rather have a high-carbon steel rotor with no slots than grey iron rotor with slots.

The DBA rotors on my car have heat paint which turns white when a predetermined temperature is reached. The heat paint is visible on the edge of the rotor in the photo below. Green is the coolest at 458°C/856°F. Normal street driving in my car has not even triggered this to turn white. They've never reached a temperature which triggers any of the heat paint. The point here is that the rotors aren't getting hot enough where drilling will be a benefit. They are cooling perfectly on their own without holes.

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Here is a discussion about drilled and slotted:


Personally, I am interested in checking out coated rotors (not a performance consideration) when I get around to changing the rotors on my car. Coated rotors should have less corrosion (on the parts not contacted by the pad) which, like drilling, may essentially be cosmetic.
I believe Powerstop is a respected brand but have no experience directly. Others can chime in.

Is K6931 the kit with slotted/drilled rotors and carbon/ceramic pads?

I'll express my opinion about drilled rotors.

IMO, Drilled rotors are one of the last things to consider, after everything else has been done including fully flushing the system with high-boiling point fluid, use of high carbon steel rotors and the best pads you can find, braided stainless hoses, replace all hardware kits and hyper-anal meticulous cleaning and assembly of all parts.

Rotors are drilled to increase surface area and thereby increase cooling. The downside is that it also reduces mass and therefor, the amount of heat a rotor is able to absorb. More mass = ability to stop harder and stop more often before the brakes fade. Keep in mind that race cars have massive rotors to begin with and so drilling still leaves a lot of mass. Race cars also have cooling ducts which direct fresh air to the brakes. I think for most street cars with small-ish rotors and no cooling ducts, drilling probably reduces performance. I've no numbers to prove this but that is what I suspect.

Drilled rotors sometimes experience cracking around the holes. I don't know if manufacturers have fixed this since I first read about it but it is a concern of mine. As an example, Porsche doesn't drill their rotors but casts their blanks with holes. The holes are then finished with the rotor surface. This is done to prevent cracking but it raises cost. Porsche rotors can be $1500 each.

Everyone is free to do what they want and drilled rotors look killer. I however, would focus on
1) flush with good quality, high-boiling point fluid such as Motul RBF 600 or ATE 200
2) Use high-carbon steel rotors. "High Carbon" is a grade of steel. Call or email the manufacturer and ask what their rotors are made of. If they say "Gray iron" or some other grade then it isn't high carbon.
3) New hardware kits and meticulous assembly. Don't forget to scrub the rust off the hub to rotor mating surface with a wire brush.

Consider using a slotted rotor if you are using an aggressive pad. I don't consider ceramic to be aggressive. Slotting helps to move dust and gasses away from the friction surface and removes negligible mass. I'd rather have a high-carbon steel rotor with no slots than grey iron rotor with slots.

The DBA rotors on my car have heat paint which turns white when a predetermined temperature is reached. The heat paint is visible on the edge of the rotor in the photo below. Green is the coolest at 458°C/856°F. Normal street driving in my car has not even triggered this to turn white. They've never reached a temperature which triggers any of the heat paint. The point here is that the rotors aren't getting hot enough where drilling will be a benefit. They are cooling perfectly on their own without holes.

View attachment 580455


Yes, I read that the drilled rotors would crack overtime. And worse, I read some reviews said that Powerstop brakes were good only when under 10K miles, after that they started to lose power or warped. I think better go for OEM.
But I called Subaru parts online in US today, they could not help me with the rotor diameter, because the VIN that I gave them did not show up (Canadian car). Do you know the part number of the rotors with front rotors' diameter 316mm (XT), or they are just similar with the 17" wheel XT? I'm trying to avoid buying locally because the price is about double. I can just drive to the border and pick up. Thanks.
@mikforxt18

OE parts can be looked up at parts.subaru.com.

I just tried to look up the rotor part numbers and now I'm very confused.

They list some rotors under 16" and 17" sizes. There are no such thing.

Others are listed as fitting both the XT and non-XT vehicles. That doesn't make sense. There are definitely two different size rotors for XT vs non-XT.

I don't know what to say other than try Rock Auto or Buy Brakes.
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Everyone is free to do what they want and drilled rotors look killer. I however, would focus on
2) Use high-carbon steel rotors. "High Carbon" is a grade of steel. Call or email the manufacturer and ask what their rotors are made of. If they say "Gray iron" or some other grade then it isn't high carbon.

Consider using a slotted rotor if you are using an aggressive pad. I don't consider ceramic to be aggressive. Slotting helps to move dust and gasses away from the friction surface and removes negligible mass. I'd rather have a high-carbon steel rotor with no slots than grey iron rotor with slots.
+1. If you were to look for high carbon brake discs/rotors, Brembo Sport and DBA 4000 and 5000 series are top tier. Anything beyond that and you're getting into race type stuff

I have Brembo Sport slotted front brake discs on mine and have been thoroughly happy with them. I would have no issue going with the DBA 4000 T3 slotted or HD non-slotted series of discs either.
Brembo Sport pads and DBA pads would be highly recommended too - Depending on which compound you went with from DBA for your application OP. Performance Friction and Pagid Fast Road and Track compound pads are also extremely well respected globally and would make great options far and above the performance of OE spec discs and pad friction material..
@mikforxt18

OE parts can be looked up at parts.subaru.com.

I just tried to look up the rotor part numbers and now I'm very confused.

They list some rotors under 16" and 17" sizes. There are no such thing.

Others are listed as fitting both the XT and non-XT vehicles. That doesn't make sense. There are definitely two different size rotors for XT vs non-XT.

I don't know what to say other than try Rock Auto or Buy Brakes.
How about Centric brakes, there is one fit perfectly to Forester? Centric 906.47033. I read some good reviews about Centrics.
+1. If you were to look for high carbon brake discs/rotors, Brembo Sport and DBA 4000 and 5000 series are top tier. Anything beyond that and you're getting into race type stuff

I have Brembo Sport slotted front brake discs on mine and have been thoroughly happy with them. I would have no issue going with the DBA 4000 T3 slotted or HD non-slotted series of discs either.
Brembo Sport pads and DBA pads would be highly recommended too - Depending on which compound you went with from DBA for your application OP. Performance Friction and Pagid Fast Road and Track compound pads are also extremely well respected globally and would make great options far and above the performance of OE spec discs and pad friction material..
Thanks for the info. I'm more looking to change the brakes, not upgrade them. Actually the OEM is enough for me, but local dealer is selling almost double the price of US dealer, so I'm still looking around. When I was very young, I had Subaru impreza WRX, and now I could tell that the Forester's brake is nothing special at all, nowhere near the impreza's brake. So aftermarket brands won't be worse than the already-bad Forester OEM brake. LOL. Looking for something that will fit perfectly and last at least the same with OEM (35K miles/50K kms). I read Powerstop is only good in the first 10K miles.
Guys, regarding bleeding the brake and changing rotors and pads, do I :
1. Change rotors and pads on a wheel, then bleed that wheel, and move on to another wheel and do the same, or
2. Change rotors and pads on all wheels first, then bleed all wheels, or
3. Bleed a wheel, then change rotors and pads on that wheel, and move on to another wheel and do the same, or
4. Bleed all wheels first, then change rotors and pads?
I like to flush my system when I do the brakes.
Change rotors and pads on all four wheels first.

Bleed/flush all four wheels last.
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