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2006 Forester 2.5X 4EAT
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Discussion Starter · #1 ·
I know it has been asked many times, but I've yet to find a definitive write-up. So having just completed mine, here's the steps I used:

First off, here's a shot of my busted drum brake, notice the right piston stuck in the open position:


Here's a shot of the drum brakes that I started with


Here's a shot of my (near) stock suspension, since in changing from drum to disc I also changed out my end links and lateral links
 

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2006 Forester 2.5X 4EAT
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168 Posts
Discussion Starter · #2 · (Edited)
Drum-to-Disc Conversion + lateral links + endlinks - Part 1

On to the swap!

General Note: I'm having fitment issues on my tires post-swap. Specifically, I'm running '05 WRX wheels (16x6.5 w/ 55 offset) and I'm now getting rubbing on my strut from my Continental's (225/55/16). It appears, from a rough measurement, that from the back of the dust plate to the base of the studs is about 5-6mm different between drum and disc. This was enough to cause some rubbing, but can be cured by either a) thinner tires, b) shallower offset, c) wheel spacer, or d) any combination of the above.

Overall Process:
- Disconnect and remove e-brake cable from interior
- Disconnect connecting lines at drum hub (brake, ABS, e-brake)
- Remove drum hub assembly
- Install disc hub assembly
- Run e-brake lines
- Reinstall connecting lines at disc hub (brake, ABS, e-brake)

Overall Parts Needed:
- Disc e-brake cables
- Disc calipers
- Disc Rotors
- Disc hubs+knuckles
- Brake fluid
- Brake Bleeder kit
*- Axles
*- Trailing arms
**- E-brake hardware kit (springs, etc for e-brakes)
* Optional, makes things easier, especially the axles
** Optional, but highly recommended

Overall Tools Needed:
- Jack
- Jack Stands
- Brake Fluid
- Brake bleeder kit
- Copious amounts of PB Blaster
- Liquid catcher for brake fluid
- Philips screw driver
- Flat-head screw driver
- 8mm deep socket or wrench
- 10mm socket or wrench
- 12mm socket or wrench
- 14mm socket or wrench
- 2x17mm socket or wrench
- 2x19mm socket or wrench
- 15/16" Wrench (or near equivalent)
- 1/2" &/or 3/8" breaker bars depending on your socket sets
- Diverse swear word vocabulary
- Gloves
- Safety Goggles

Remove e-brake cable from interior: (Sorry no pics atm, I'll try to go back and get them)
Tools Needed:
- Philips screw driver
- Flat-head screw driver
- 8mm deep socket or wrench
- 12mm socket or wrench
- 14mm socket or wrench

Note: I did this step last. It worked, but it was also a pain because a) I was dirty and got gunk all over my interior and b) pushing the e-brake cables 'up' from under the car was a pain that I think is more easily achieved by pushing the cables down from the interior.
1: Open the tall portion of the center console, there are 3 screws at the bottom, remove them
2: There are two screws at the front of the tall part of the console that connects it to the cup-holder portion, remove them
3: Pry up the plastic facia in front of the shifter (portion with the 12V plug and ashtray), turn the key and place the car in neutral with your foot on the brake, then set the facia you just pulled off to the side. I didn't bother disconnecting the cable for the 12V plug. Put the car back in park and then turn off the key
4: Unbutton the e-brake boot and remove the screws in the plastic that were covered by the plastic facia
5: Pry the forward side panels off the cup holder section and remove the cupholder section by lifting straight up, set aside
6: Disconnect the 12V plug line running to the tall portion of the center console
7: Remove the bolts holding the tall portion of the center console, 2 in the front (under the head unit) and 1 towards the middle, around where the shifter is, remove the tall portion of the center console and set aside
8: Remove the back seat by removing the 2 bolts in the footwell of the rear of the car
9: Unhook the carpet by peeling up the plastic tab in the middle of the back seat (helps to use a flat-head screw driver to get the plastic tab up)
10: Pop the grey plastic retainer button seen on the back seat deck near the door and pull up the plastic cover (mount points: door metal edge, 2x'foot' of door frame) - Do this on each side
11: Begin peeling back carpet to reveal the center footwell area up to where the center console was, exposing the entry points for the e-brake cables and the retaining clips bolted into the floor that hold the cables
12: Loosen the 2 nuts on the e-brake tensioner, push the cable down to produce slack in the e-brake cables.
13: Follow that cable to the 2-to-1 clip that connects the two e-brake cables to the tensioner cable. Turn the clip to one side and free a cable, do the same for the other cable.
14: Unbolt the brackets hold the e-brake cables in place, push the e-brake cables through the floor.
15: Take the new e-brake cables and push them through the floor. Attach the new cables to the tensioner bracket and re-install the brackets holding the cables in place. Don't worry about tightening the tensioner cable at this point.

Onto the fun stuff:
*** = Only necessary if replacing the lateral links, as I did
**** = Only necessary if the donor disc wheels have trailing arms or axles

Tools Needed:
- Flat-head screw driver
- 12mm socket or wrench
- 2x17mm socket or wrench
- 2x19mm socket or wrench
- 15/16" Wrench (or near equivalent)
- 1/2" &/or 3/8" breaker bars depending on your socket sets

1: Jack up your car and set it on jack stands. I did one side at a time, especially after what happened earlier.
2: Remove the tire

Alternative Note: If you do not have an axle to swap in, now would be a good time to have a friend stand on the brakes and, using a 32mm socket, knock loose the hub nut holding the hub to the axle
3: Take a 10mm wrench and loosen the brake line Then take a flat head screw driver and pull out the tab holding the brake line in place. Once that is done, take your new caliper and zip-tie it to the spring. Connect the caliper to the hard line to help prevent air and moisture from entering the system. This will make bleeding easier later:

4: Use the same screw driver to pop the tab on the strut holding the brake line:

***5: Remove the end link, at the very least the lower portion connected to the lateral link, mine were 17mm bolts and nuts

6: Remove the bolt connecting the lateral links to the knuckle. This was a particularly tight bolt, requires 2x19mm. I used a 1/2" drive breaker bar and a 19mm wrench, and it was still hard. I actually put the bolt back in at least part way just to keep things stable as I removed the rest of the pieces.

7: Remove the bolts connecting the knuckle to the strut housing. Again, these are 19mm bolts and are a pain to get out if you haven't removed changed out your suspension recently. I left the top bolt in again for stability.


Alternative Note: If you are removing the trailing arm, there is also one last bolt in addition to the 2 below that secures the ABS and e-brake lines to the trailing arm, close to where the trailing arm attaches to the frame. I found it easier to remove this bolt after the trailing arm is off. If you are not removing the trailing arm, then you will need a 12mm wrench to remove the bolt as there is no clearance for a socket.
****8: Next I removed the bolts holding the ABS and e-brake lines from the trailing arm (12mm). Following that, I removed the ABS sensor from the drum brake assembly (12mm). Additionally, at this point you will want to crack open your drum brake and disconnect the e-brake line from the housing (not pictured):


Alternative Note: If you do not have a new trailing arm to swap in, remove the trailing arm from the knuckle using what I presume is a 19mm socket combo (not verified)
****9: Next, I removed the bolts holding the trailing arm to the frame:


Alternative Note: If you are not removing the axle from the diff, now is the time to go ahead and finish removing the axle from the hub. There are numerous guides on how to do this if you are unsure
****10: To remove the axle from the rear diff, insert a wrench (I used a 15/16", but it just needs to be narrow enough to fit in between the diff and the green part of the axle) into the space, brace it against the diff, and then smack it a few times. The axle should pop right out after a few tries.



11: Remove the strut bolt and lateral link bolt holding the knuckle assembly in place and remove whatever part of the assembly you have the parts to replace:

Alternative Note: If you are not replacing the lateral links, ignore this step.
Alternative Note: If you are replacing the lateral links, but are not swapping the axles, simply use 2 17mm wrenches and a cheater bar + some hefty swearing
****12: Use a 17mm socket and a breaker bar to remove the nuts and bolts connecting the lateral links to the frame. You'll need a 17mm wrench for the front-most nut on the front arm. A 17mm socket and a breaker bar work miracles for the two inside nuts/bolts.
 

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2006 Forester 2.5X 4EAT
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Discussion Starter · #3 · (Edited)
Drum-to-Disc Conversion + lateral links + endlinks - Part 2

***13: Attach the new lateral links. I hand-tightened these so that they would stay up but could still be moved when I needed to align them after I inserted the new axle/knuckle/hub/trailing arm assembly.

14: Put the new assembly in place, sliding at least a strut bolt to make sure you don't have to hold it up:

****15: If the axle doesn't get inserted properly, you will likely have to rotate it a little bit until it can slot into place. It should look like it did after you 'popped' it out during disassembly:


****16: To insert the axle, from the wheel well, put your thumbs on the base of the hard green part and simply push in, you'll feel a satisfying pop


17: Begin the process of removing the old e-brake cables and attaching the new ones. I found it easiest to remove a screw and then immediately mount the new one in its place.
18: Attach the new e-brake and ABS cables to the top of the trailing arm
***19: Reattach the new trailing arm to the frame
Alternative Note: Reattach the trailing arm to the new knuckle
20: Adjust the lateral links and insert the long bolt through the links and the knuckle
21: Reinsert and tighten the strut bolts and nuts
Note: My e-brake came completely disassembled, so I had to reconstruct the e-brake at this point. I used this and this to reassemble my parking/e-brake
***22: Tighten the lateral links using 2x17mm wrenches and all your might
23: Reattach your ABS using the 12mm bolt to the rear of the brake and trailing arm (if removed)
24: Put your disc rotor on over the e-brake assembly
25: Put the caliper on, attaching the brake line to the hardline and re-inserting the retainer tabs.
26: Put the wheel and tire back on, marvel at your accomplishment



Now repeat for the opposite side.

But wait! There's more!
1: Back in the interior (which is still ripped apart), begin tightening the e-brake tensioner. There is some discussion as to how many clicks is appropriate, but really I feel it is whatever you are comfortable with.
2: Once at the appropriate tightness, reassemble the interior by reversing the steps from above. Make sure you clean out the e-brake boot while you're at it, no one likes 6-year old french fry crumbs

Once fully assembled, bleed the brakes THOROUGHLY!!!
 

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2004 Forester XT Premium 4EAT
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Very nice write-up. I've added a link to this thread in our Knowledge Base.
 

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2006 Forester 2.5X 4EAT
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168 Posts
Discussion Starter · #7 ·
Proportioning valve is the only thing I see missing.
Without at all saying you're wrong, I hadn't seen this on any of the various parts lists or builds that I came across.

Is it a limited use part (ie: track) or something that is recommended regardless of the application?

I'd definitely like to know if it is a necessary component, as I clearly am not running one at present
 

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2008 Forester XT Sport 4EAT
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Your are running one, you're just running the drum one.

In your research did you find people saying that they didn't notice much of an improvement? That's because they didn't replace the proportioning valve.

It should be installed on the passenger strut tower. Trace your brake lines, this will have two hard lines going to it.

Sent from my phone, sorry for any typos or brevity
 

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Discussion Starter · #9 ·
And my ignorance shines bright :icon_eek:

I did see reports of people not noticing a difference. Do I need just an OEM disc valve? I know there are adjustable aftermarket valves, but those seem like overkill.

Is it a requirement to brake properly, or is it just something that is going to make me feel the difference from having "better" brakes in the rear?
 

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2014 Forester 2.5i 6 spd
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Drum brakes actually produce more stopping power per psi of brake pressure than disc brakes. So, if you have a disc front and drum rear setup, the proportioning valve limits the amount of pressure delivered to the rear brakes so that you don't lock the rears up before getting proper stopping pressure on the front discs.

Keeping the wrong proportioning valve in place causes the system to only deliver the correct brake pressure for drum brakes in the rear. It's not delivering the higher, necessary pressure for the rear discs to be fully effective. The OEM valve would be sufficient for most of us. The F1 cars have driver adjustable brake bias to suit the driver/course/conditions/fuel load-that's wee bit much.

BTW, the really big advantage to discs, is that water doesn't have much effect and they resist brake fade under severe braking much, much better than drums.
 

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Discussion Starter · #12 ·
The OEM valve would be sufficient for most of us.
That's what I was looking for. If I can find one eventually I'll probably swap it out, else I have other mods on the list to do.

Drum brakes actually produce more stopping power per psi of brake pressure than disc brakes.
For me it was less about what was better, it was that I broke my drum and needed to either fix the drum or use the disc swap parts that I already had. Plus I like the look of the disc/rotors better than drums.

Had nothing to do with performance for me and everything to do with preference and necessity.
 

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Discussion Starter · #13 · (Edited)
Something else that I've noticed that I wasn't aware of prior to the swap. It looks like my disc setup is narrower than my drum setup. I'm running '05 WRX wheels (16x6.5 w/ 55 offset) and I'm now getting rubbing on my strut from my Continental's (225/55/16).

I did a quick measurement as best I could and it looks like the drums, from back of rear plate to base of the studs, is about 5-6mm deeper than the same distance on the disc setup. I don't think it would have been a problem had I been on my stock 48et wheels, but with my 55et, and having a wider tire, I'm getting some rubbing.

Just letting everyone know that there is definitely a depth difference between the two setups. I've made a note of the difference in the how-to

Update: Fixed the rubbing with 3mm spacers
 

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Discussion Starter · #14 ·
Another suggestion that I received was to zip-tie the new calipers to the springs and connect them to the brake hard lines as soon as you remove the drum lines. This will help to keep air and moisture out of the system and make bleeding easier at the end.

This has been added to the how-to in step #3
 

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2005 Subaru Forester 2.5x
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Seems like a lot of work to switch to discs, my drums works fine as long as they're kept adjusted. I recently upgraded my front brakes with new Wagner rotors and AKEBONO HP pads. It like driving another car now, wow! Unless your going to be racing, I'd stick with drums and better front brakes. A huge improvement in performance and without the expense and time utilized in your conversion. Keeping your drums adjusted may have averted to piston overextending in the wheel cylinder.
 

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Discussion Starter · #16 ·
Seems like a lot of work to switch to discs, my drums works fine as long as they're kept adjusted. I recently upgraded my front brakes with new Wagner rotors and AKEBONO HP pads. It like driving another car now, wow! Unless your going to be racing, I'd stick with drums and better front brakes. A huge improvement in performance and without the expense and time utilized in your conversion. Keeping your drums adjusted may have averted to piston overextending in the wheel cylinder.
Whole heartedly agree. I originally bought the swap parts because I like the look of the discs over drums.

The reason that I did the swap when I did it was because I unsafely put the car on jack stands on an unlevel surface and had a mishap. When the car (with both rear tires off) slid off the jacks, the right rear hit the sidewalk hard enough to bust the piston and leave it in the open position. Try as I might, I couldn't get the piston back in and so I was forced to do the swap since I already had all the necessary parts.

I was never unhappy with my drums and they really did work just fine. For me it originally was about looks then became a necessity. I really am not an advocate for either setup, to each his own.
 

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Discs have their advantages being a firmer pedal, but warpage is much more common with them leading to more brake service. Drums actually offer more contact surface and maintained right (kept adjusted) will work great in-concert with quality front brake components. Drums also greatly out last rotors. For all these reasons, that's why big rigs use them, Semi tractor trailer and other large trucks. This is what you need: The ProAct set: Akebono: Aftermarket Products and Services Look up your application or find them on Rockauto.com. They're excellent, far better than OE.
 

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I did the same swap back in January, even have the same rims that you have (except mine are in there natural color), the only thing that I did different was to change out the valves on the calipers so that it made it easier to bleed. I do not have the problem that you mentioned with rubbing, but then of course did not change out the links. I left it stock otherwise and have had no problems with the tires rubbing (standard Michelins). I bought all 4 knuckles from a WRX for 200 and have the front calipers as spare (they are identical to those of my 07 Forester). It actually was not that hard to do, as all of the parts are identical, and besides it came with the e-cables attached, what took a while was to undo all the bolts from the old cables, and of course the interior work to swap out the cables.....
 

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Discussion Starter · #19 ·
I do not have the problem that you mentioned with rubbing, but then of course did not change out the links. I left it stock otherwise and have had no problems with the tires rubbing (standard Michelins).
I think that the issue was that my tires were just a little wider than stock. With a 3mm spacer, I have clearance. It could have been due to the lateral link swap, but from what I remember the STi and Forester lateral links were the same length. I know my track set on 48et offset clear with no problem and no spacers.

besides it came with the e-cables attached, what took a while was to undo all the bolts from the old cables, and of course the interior work to swap out the cables.....
Were the parts and cables you got from a WRX wagon? I found a set of cables off a Fozzy part out, as I was led to believe that the sedan cables would be too short. It would be good to note in the how-to specifically what would work for others.
 
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