00WRX(4-pot) Brake Upgrade;MY01-07 GX/RX/RV/RS;pre99WRX

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00WRX(4-pot) Brake Upgrade;MY01-07 GX/RX/RV/RS;pre99WRX

Postby 05-RSX » Mon Jul 09, 2007 1:41 am

DIY: 00WRX (4-pot) Brake Upgrade for MY01-07 GX/RX/RV/RS; pre-MY99 WRX; some Forester models (unsure which)
By Campbell Watson (05-rsx)

So you have these?

But you want these?

From Day-dot when I got my RS, I’ve always wanted what I knew as ‘those big WRX brakes’ and what I’ve come to know as ‘4-pots’. And now I finally have them. In two words – ‘LOVE THEM!’.
Originally I also wanted the 2-pot rears, but that required a lot more work (read: money) to achieve, and at the price I got them, they were too good to refuse (BIG thank you to Frankie!)
Note; I didn’t say the 2-pot upgrade was impossible, far from, just a lot more money, for not much more than aesthetics for the uses I had for them – like try interchanging rear hubs for a start, or getting Kartboy adapter brackets for ~250 US I think they are! Exactly, not an at home DIY job for me either.
And while I was at it, I (again) decided to take some pictures to form a DIY for those who may wish to do it in the future.

Important notes:
-This DIY may strike a remarkable resemblance to my Headlight Clearing/Amber removal DIY. I assure you it is pure coincidence and has a 0% chance me just being ‘lazy’ and copying the format and many sentences from the other. Because any person with common sense and/or sense of time managing would do that! Anyway, on with the actual important notes:
-Read the whole DIY first, before beginning it.
-Not all wheels clear these big 4-Pot calipers. Ensure yours do before embarking on this modification.
-Do one side at a time, that way if you bugger up and forget how it went back together, you can refer to the other one that's still good as you haven't touched it yet.
-IMO, its best to keep your work area as clean and tidy possible throughout. Don't adopt an OCD, but just be mindful.
-Brake fluid is corrosive. It is the ultimate paint stripper, and does wonders for exfoliating skin. Henceforth be very careful. Do not spill it on painted areas, and avoid contact with skin. Wash off ASAP.
-Be careful, take your time, and don’t rush. When you rush, is when mistakes happen (I know I'm sounding like your parents, but there's truth behind it)
-Standard disclaimer: If you bugger up because you blindly followed this DIY guide, it's not my fault. I did not cause you to make the mistake, nor even do the mod. Below is the way I did things, which turned out to be successful, either by method, or chance.
Also, if you violate any legals (road rules, automobile design rules, etc) by doing this modification to your automobile, I accept no responsibility - check the rules before you do anything.

Took me, as a 'first-timer', single handedly, around 3-4hrs. I cannot remember exactly. I was actually surprised how quickly I got it done - I was expecting a full day job.

-‘SUBARU’ 4-pot calipers with pads and discs to suit. 4-pots use a larger 295mm disc, as opposed to the 277mm disc you currently have, pads are not interchangeable between 2 and 4 Pot calipers.
-MY99-00WRX rear calipers with pads and discs to suit. You are upgrading from solid to vented discs, although both are 266mm, there’s your first difference; pads may be interchangeable between rear calipers, I don’t know, mine came with! The 99-00WRX caliper is physically wider, as you will see in later pictures.
-8x copper crush washers for brake line – caliper attachment (2xeach caliper). Optional according to some mechanics. Still, cost me $9.50 from RaceBrakes (*Cough*, free plug *cough*), didn’t even mention anything about any WRX club. Better safe than sorry - it’s only $9.50.
-Front heat shields, for larger rotors, again optional, but more so this time (if possible). Mine came with fortunately, so I figured why not chuck them on as well.
-Brake Fluid. I bought 2-bottles of Castrol SRF Dot4 envisaging the garage floor being coved with the stuff from me spilling it everywhere. Only ended up using about ½ of one. However, that said, I had already done a complete system flush with it 2 months prior. If you’re still running stock or old fluid, I strongly recommend a complete system flush, and you may as well get some decent fluid while you’re at it.
-12mm Socket
-14mm Socket
-17mm Socket
-17mm Ring spanner (if the socket doesn't fit between the caliper and the strut, its a bit tight in there)
-Tyre iron/suitable socket (¾”) to remove wheels.
-Suitable ratchet for 12mm socket
-Small breaker bar for 14mm & 17mm socket.
-Medium Flat-head screwdriver
-2x M6 or M8 bolts (Can’t remember which one, the smaller of the two)
-Rubber Mallet
-10mm spanner. I think its 10mm. To fit the bleeders on the back of the calipers. Check the 4-pots that you have in the box, because I can’t be bothered taking my wheels off at 12.30am during winter.
-Old bucket for catching and misguided brake fluid.
-Car jack. No, not that crappy excuse one Subaru gives you in the rear, a real one fool.
-At least 2 jack stands. I had 4, which saved time, as I could get the whole car in the air at once.
-One MY01-07 GX/RX/RV/RS; pre-MY99 WRX; or some Forester models (unsure which) with 277mm, 2-pot front brakes and 266mm solid, 1-pot rear brakes; along with the serious want to upgrade them. (this mod is not for the faint hearted. Having said that, if you take your time, and are careful; like all things, it should be fine)
For males: One set of large balls.
For Females: Knowing that you may possibly be wrong in the near future (shock); alternatively, a male who fits the above criteria.

Step 1:
Acquire car with a set of these (as with last DIY, may also have additional drag-creating bonnet scoop):

Step 2:
Crack wheel nuts, set handbrake, set in gear, jack car up at specified jack points, lower onto jack stands, remove wheels. Then, REMOVE HANDBRAKE (or the rear discs will never come off)

Step 3:
We’ll start with the front first, as lets face it, you can’t wait to get those 4-pots on, and so we’ll go with your excitement and start there.
-MY00 Impreza: Remove the clip holding the brake lines to the strut. I used a medium flat headed screwdriver and a little persuasion from a mallet (just a soft tap, its not that fixed).
-MY01+ Impreza: The Brake line is held on by a single 12mm bolt, simply undo this and the brake line with its fastener should come free of the strut.


Step 4:
Remove the front caliper from the hub. 2x 17mm bolts, pictured below. Then just let it hang gently.

Step 5:
Remove front disc. Mine where not very fixed, and with the amount of jiggling I had done trying to remove the caliper; it had also unbound the disc from the hub. It it’s still stuck, insert the 2 M6/8 bolts into the 2 small threaded holes in the disc, and alternate between tightening each after a few turns until the disc ‘pops’ off.

Step 6:
If you got your hands on the bigger heat shield, now is the time to swap them over. Pretty simple really – 3x 12mm bolts & Logic. There is a left & right though, make sure the ‘body’ of the shield is on the front side of the hub.


Chuck on the 295mm discs. You can do it after you bolt on the 4-pots, but then you have to leave the calipers hanging suspended from the lines whilst you do it, and they’re fairly heavy, so I would advise against.

Step 7:
Now it’s time to remove those pesky 2-pots! I cracked the brake line bolt by just loosely attaching the caliper back onto the hub to hold it, then removed the caliper again.
However, before you do this, here’s a nifty trick to stop/significantly reduce the amount of brake fluid you’ll spill everywhere:

2x scrap bits of 2x4, and the seat moved all the way forward, with the wood ‘jamming’ the pedal on. This way it closes the fluid reservoir from the rest of the system, so you may leak a little bit, but then it’ll stop. Be sure to remove your brake light fuse too, or you’ll flatten your battery and get your bulbs very hot. Mine fuse was labeled “STOP” in the ‘in-cab’ fuse box.
Depending on whether God is deciding to give you a tough day or not, you may have to disassemble and re-assemble this setup every time you want to remove another caliper, as otherwise the fluid is pushing on the piston, pushing on the disc, holding the caliper to the disc, preventing you from removing it. See how you go though.

Back on track, simply unscrew the brake line bolt, preferably over the bucket, and make sure you identify/separate the crush washers, either for reuse, or disposal (they can sometimes stick to bits and ‘hide’.
Take note the order of the washers: Banjo bolt, washer, brake line (terminal) washer, caliper.
And remember brake fluid is the devil.

Similar to the last DIY, this is the point where the parent(s) walk out to see how things are going, even if they have no idea how to assess the situation or offer any assistance. This time it was Dad, however, unlike Mum, he was intelligent enough not to ask any questions and just walked back inside.

Step 8:
Basically doing what you just did in reverse, bolt up your 4-pots to your brake lines. Don’t forget the crush washers, either reused or new. Torque specs at the end of this DIY.
*There IS a left/right caliper! Bleed valve should be on the UPPER half of the caliper when installed.

Then slide them over the disc and bolt then back up with the 17mm bolts.
Reattach the brake lines to the strut.

Step 9:
Repeat steps 1-8 on the other side.

Step 10:
Again, first start by removing the clippy thing. This time, all models have a spring clippy jigger holding the brake lines to the strut. (Refer to step 3 for method)

Step 11:
Unbolt the caliper. This time it’s 2x 14mm bolts just to be different.

Step 12:
Make sure the handbrake is OFF. Otherwise the drum component on the inside of the disc will be holding it firmly in place, rendering all your feeble attempts to remove it useless.
Swap the discs over, using the same method you used for the front.
Some more comparison pictures of the discs:

Step 13:
You’ve probably already got the hang of switching the calipers over now, so just do what you do best, again, there is a left/right for the rear, make sure the bleeder is up.
More Torque specs for the rear at the end of the DIY
Some caliper comparison pictures for good measure:

Step 14:
Double check EVERY bolt you touched, looked at, sneezed towards during the DIY. These are your brakes we are talking about. If something goes wrong because you were lazy and didn’t bother to check then you are without brakes. If you are without brakes, then put bluntly, your flucked.

Step 15:
Grab a mate/brother/parent and bleed your brakes to remove the air bubbles you’ve put in the system during installation. This is also where it’s handy to have 4-jack stands.
Consult the manual for bleeding order (I did mine one way, and it worked, either by chance, or method, I have heard many conflicting orders that are the ‘correct way’)
More or less:
-Attach a small length of thin tube to the bleeders.
-Pump up the pressure up in the system by pumping the brake pedal a few times.
-Hold the pressure on the pedal.
-Signal when ready
-Un nitch the bleeder a little bit to let brake fluid escape. You should get all types of wonderful colours and noises happening. Keep constant pressure on the pedal as it heads towards the floor; no not release it until signaled.
-Nitch the bleeders back up.
-Now you can release the pedal and pump it up again.
-Continue to fluid is either flushed and/or clear and/or has no air in it.
-Move to next wheel in the sequence.

Step 16:
Double check every bolt again. Make sure you’ve attached all the brake lines to the struts (I forgot, then found some springy things just after I’d put the wheels back on.

Step 17:
Re-install wheels, take car off jack, torque up wheel nuts.

Step 18:
Start the car. Pump the pedal a few times to make sure:
a)It goes hard after a few pumps (no air/leaks)
b)To push the pads back into position on/next to the discs

Step 19:
Take a slow, leisurely drive to make sure everything it working and not making any weird noises.

Step 20:
Marvel in your own glory.

Step 21:
Stare, obsessively at the 4-Pots.

Step 22:
Accept the fact that you managed to follow a DIY some 19y.o. kid made.

Step 23:
Grossly enjoy the new aesthetics and braking performance of your new setup.

Torque Specs:



Some after/during pictures:







Last edited by 05-RSX on Mon Jul 09, 2007 12:44 pm, edited 1 time in total.

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Postby cpitts » Mon Jul 09, 2007 12:34 pm

Superb write up Campbell!!

How much better is the braking now? (like I need to ask)

Can you give a % improvement over stock? (100%, 200%, etc)
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Postby 05-RSX » Mon Jul 09, 2007 12:52 pm

2 more pictures added - 1 ea. on 3 & 8 (yes, I had to go out and pull apart the car again, then custom MS paint it up)

Everyday braking 'feels' much the same through the pedal, the total piston area of the 2-pot is only slightly bligger than the 4-pot. However the car seems to wipe off speed much faster.
The response is a little crisper, but not quite as much initial bite as the 2-pots. I think this has a lot to do with the pad change too. And therefore can also be changed to my liking in the future.

I dare say fade resistace is also a whole lot better. I never really got a good chance to work my 2-pots that hard, except once on the GOR, where the pedal got a bit soft for my liking at some points; where as the reefton cruise on went on the other day with v1cwrx, i was working them pretty god damn hard (probably the hardest ive worked brakes) and didnt have a single issue, they were always there 100%! :D :)
So, street/DD: 50-70%
Evil Twisties: >100% unsure of how much as cant honestly compare apples to apples.

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Postby MnMredrex » Wed Jul 11, 2007 5:40 pm

Mate that is one great write up.

It would have taken you longer to do that than the actual job!
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Unless you are one on one.

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Postby 05-RSX » Wed Jul 11, 2007 5:49 pm

In fact, now I think of it, it did. :oops:
10am-1pm for the brakes
-a few weeks later :oops: -
9pm-1.30am for the DIY.

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Postby Dances with Fences » Wed Jul 11, 2007 7:24 pm

Good job mate! What rotors you running on the front there?

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Postby 05-RSX » Wed Jul 11, 2007 11:09 pm

Just some DBA650s all around at the moment mate. DBA4000s (only slotted) will be replacing them when they wear out.

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Postby MrEs » Fri Nov 09, 2007 1:22 pm

Promoted to FAQ section.. TOP STUFF!!! :cheer:
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