[williaty]

NOTES:
1) All sockets and wrenches used must be 6-point due to the high torque on the suspension bolts. Using 12 point wrenches makes it very likely that you will round over the head of a bolt or a nut.

2) To loosen the long bolt through the knuckle, you'll need a 6 point, 1/2" drive socket, 1/2" drive long breaker bar, and 4 to 6 feet of pipe for leverage (the handle of a floor jack will work well if it will slip over the breaker bar).

3) It is a VERY GOOD IDEA to loosen and remove the nut on the long bolt through the knuckle and move the bolt an inch or two on both sides to verify that it has not seized into the knuckle on either side before disassembly of the car continues.

4) This tutorial was shot on a USDM STi. I have also preformed the mod on 2 USDM RSes. There are some slight differences between the models. I will try to note in the tutorial where the differences are, but here's a short summation:

a) Due to the thicker exhaust piping, the driver's side rear inner lateral link bolt will be trapped by the exhaust on the STi. SHOVE HARD up and in on the exhaust and you'll be able to get the bolt out. On the RS, the bolt comes out without any drama.
b) The STi uses different rear lateral links. They're solid aluminum on the STi and steel on the RS/WRX. The STi aluminum links are sharp and will require some dressing as detailed in the tutorial. The steel links on the RS/WRX are very well machined and don't require any dressing.
c) The endlink attachment points are also different. If your car differs from the picture below and you can't figure out how to detach the endlinks from the lateral links, stop now and sell the car.

5) The STi and late model WRXes have tubular aluminum front lateral links that will require a little dressing before the bushing install. Older WRXes and RSes have a stamped steel link nicknamed the "Taco Link" because of it's shape and propensity for folding. If your front lateral link looks like this picture, order the newer-style aluminum front lateral link when you order your bushings:


6) After you have removed the bushings and dressed the aluminum links (if you have them) I STRONGLY ENCOURAGE you to practice pressing a stock bushing in several times. You will almost certainly destroy the first bushing or two you press. It's much cheaper and quicker to kill a stocker and then move on to doing all the Group N's right than to kill a Group N and have to order a new one. The reason that almost everyone kills at least one bushing is that no one believes how careful you have to be about getting it lined up until they prove to themselves that you'll kill the bushing if you're not careful. If you're incredibly pedantic and truly listen when I say things like EXACTLY coaxial, you'll probably get away with never damaging a bushing.

7) All of the pictures are links to versions twice as large. Print this view as an instruction set, then click though and print any details you feel you'll need.




List of Tools and Materials:

1) Jack
2) Jackstands
3) 2lb or heavier rubber dead blow hammer
4) 2 17mm 6-point combo wrenches
5) 19mm 6-point combo wrench
6) 19mm deep 1/2" drive impact socket
7) 1/2" drive breaker bar
8) 4-6' of pipe that will fit over the handle of the breaker bar for extra leverage
9) 12mm generic socket w/ generic ratchet handle
10) 22mm 1/2" drive socket
11) C-Clamp style Ball Joint Press (hereafter referred to as BJP, available for "rental" at Advance Auto)
12) Tube of non-graphite anti-seize (hereafter referred to as AS). Graphite will eat aluminum. A lot of your car is aluminum. Make sure the AS you buy contains no graphite. Copper AS is the most common kind of non-graphite bearing AS
13) Tube of silicone based grease (easiest to find is NAPA SilGlyde)
14) One or more receivers correctly sized for your links and bushings.



OK, so you're ready to begin! The first thing you need to do is remove the endlinks from the lateral links. If you have spherical bearing endlinks, you can probably do this one the car is in the air, however, most endlinks have to be removed with the car at ride height. So either do it on the ground, or do it on ramps. The vertical links in this picture are the endlinks. If you have a WRX or RS, the endlinks will be black and attach differently since the rear lateral link will be black steel rather than bright aluminum. If you can't figure it out, go away.


Use a floor jack to lift the rear end of the car as high as possible and place securely on jack stands. Once it's in the air, remove the rear wheels (the other order works poorly). You might want to leave the rear wheels next to the car because you're going to be sitting there quite a bit. Now we get to the meat of the issue. The first thing you have to do is to remove ABS sensor wire and parking brake cable brackets from the trailing link. In the picture below, you can see a bolt head towards the right. That has to come out. Also, you can see a bracket towards, the left. The bolt attaching that bracket is on the other side of the trailing link and shown in the second picture. Take a 12mm socket and remove them both on both sides of the car.




Removing the long bolt through the knuckle is the most forceful part of the whole thing and the most likely to stop you dead in your tracks. If your car is new, or has never lived through a winter where the DOT salts the roads, this bolt will be incredibly easy to remove. If the car has been through more than one salty winter, this bolt will be nearly impossible to remove. The STi this tutorial features was 2 months old. The bolt in question came out by pulling on it with finger tips in about 5 seconds. On my car, which had seen 2 ODOT winters, this bolt came out over the course of 4 days (sadly, not a typo) with fire, acid, impact, and the use of a press. It's a VERY GOOD IDEA to verify that you can actually get this bolt out on both sides before you proceed any farther! To remove the nut, you will need a friend with a 19mm 6pt combo wrench to prevent the head of the bolt from spinning. You'll need to take the 19mm deep impact socket and place it on the nut, then attach the breaker bar, slide the 4-6' pipe on down, and really wail on it. MAKE SURE YOU'RE TURNING IT THE RIGHT WAY! I can't stress that enough. It's easy to get confused, and at the forces involved, it's just as easy to strip or snap the bolt as it is to loosen the nut. If you do damage the bolt, the part numbers are 20540AA000 for the bolt, 900335056 for the two washers, and 20550AA010 for the nut. On two of the three installs I've done so far, I've had to replace one bolt. Once you can get the nut off, make the bolt itself move back through the knuckle a little to make sure it's actually free. Do this on both sides. The first picture shows the knuckle from the inside. The bolt you're working on here is the long one that runs through both lateral links and the knuckle, holding the entire rear suspension together. The second picture shows the nut on the bolt peaking out from behind the rotor. Also note in the second picture how you have to flip the parking brake cable around out of the way to fit the wrench in.




The picture below shows the state you're now in. For reference, this shot is from the center of the car, facing the passenger side. At the top of the picture are the inboard ends of the lateral links. The front lateral link is on the left and the rear lateral link is on the right. The second picture is a close up of the inboard ends of the lateral links, this time the front is on the left. You can see that the front lateral link inner bolt is covered by a little rubber dome that prevents the bolt from puncturing the gas tank in a collision. You also can see how the axle is going to interfere with removing the front inner bolt, but we've got a fix for that.


It's time to free the lateral links from their inboard moorings. Start by removing the rear lateral link. The inner bolt on the rear lateral link controls toe for the rear end. Therefore the rear inner bolt is eccentric AND you need to put it right back where we found it. To do this, you need to make a witness mark on the bolt and subframe so you can align the bolt properly when you re-install it. To remove the bolt, use a 22mm socket on the graduated bolt head and a 6 point 17mm combo wrench on the nut side. To remove the nut, hit the end of the combo wrench HARD with a heavy deadblow hammer. The nut is torqued too high to come of by just pulling on the wrench and the deadblow hammer method is the easiest on you and the car. When you remove the bolt, note that there's some strange hardware there. Make sure you remove the nut, thick donut washer, and thick oval washer from the front side. The thick oval washer may be hiding in the recess on the subframe that it keys into. Put these pieces back on the bolt in the correct order right now so you don't screw it up with you re-install it. The first picture shows the rear inner bolt. The second picture shows the witness mark I made so you're sure to now what I'm talking about.




To remove the front inner bolt, the first think you have to do is to remove the little rubber dome. Twist the dome 90* counter-clockwise and the dome should basically fall off. After you have the dome off, place a 17mm 6 point combo wrench on both sides. Again, you're going to need to beat on the nut-side wrench with a deadblow hammer to get it loose. Once it's loose, remove the nut and the funky flanged washer. The first picture shows the bolt with the dome on, the second picture shows it with the dome off.




The front inner bolt is currently being held captive by the axle. In fact, the factory service manual suggests removing the knuckle and axle to remove the lateral link! We're smarter than that, so do this instead. Take you're floor jack and place the pad of the jack on the bottle of the knuckle, making sure the jack isn't touching anything else (such as the rotor dust shield or trailing link). Raise the knuckle with the jack until the car just barely starts to lift off the near-side jackstand. Slide under the car and slip the bolt out (you may have to force the rubber boot to crumple a bit). As soon as you get the bolt out, drop the knuckle back to full droop. The first picture shows what I'm talking about with the jack and knuckle, and the second picture shows how you slip the bolt out past the rubber boot.




The front lateral link is almost, but not quite, symmetric. This makes it very easy to confuse which end is inboard and outboard. You need to mark the link in some manner. I prefer to mark the link with a spring loaded center punch with 3 divots in a line (for O-U-T) on the outer end. Every time I've marked it with a marker or paint, I've managed to rub the mark off during dressing.

Once you have all 4 lateral links off the car, it's time to remove the stock bushings from the links. To do this, you'll need several things. First of all, you'll need a C-Clamp style Ball Joint Press (BJP) from Advance Auto or a similar store. You'll also need one or more receivers. Receivers are basically hollow cylinders that fit between the anvil of the BJP and the lateral link to give the bushing somewhere to go to. The ID of the receiver needs to be just barely large enough to allow the bushing to pass through it while the OD needs to be large enough to support the lateral link itself. It's possible, though not likely, that one of the receivers included in the BJP kit will be right. The easiest way to find your own receiver is to go to a large home improvement store and walk around the plumbing section. Pipe fittings come in a large variety of forms and sizes. Take a new bushing with you (so you don't have to disassemble the car first) and find 2-3 fittings that the bushing will just fit into. That way you have some options once you get to the install. If you have an STi, you'll be able to use the same receiver for both the front and rear link. The rest of us will end up needing two receivers because the front and rear links are a slightly differently design and will need slightly different receivers. I ended up with a double-male fitting for the front link (this is also what I used on both links for the STi) and a double-female fitting for the rear link (the way it flared inward "cupped" the lateral link just right) of the same size. Your mileage may vary.

The first order of business for the actual bushing swap is to clamp the BJP frame into a vise. You can do it by just holding the BJP frame as well. I've done both. Trust me, you want to clamp it in the vise. Thread the plunger into the BJP frame and find a socket to fit the end of the plunger. Place the receiver against the anvil of the BJP frame and place the lateral link against the receiver so that the bushing will pass into the receiver. Tighten the plunger until it just contacts the bushing and everything will stay put without you holding onto it. Here is where you need to start believing me when I say things like EXACTLY. You need to make sure the anvil, receiver, bushing, and plunger are EXACTLY square to each other. You need to make sure that they're all EXACTLY coaxial (meaning all lined up in all planes). You need to make sure the plunger is hitting the bushing EXACTLY in the center. Once you've lined everything up PERFECTLY, go ahead and tighten the plunger until you hear the bushing "crack" out the other side of the link and drop into the receiver. The lateral link should fall over at this point. Congratulations, you've just removed a bushing. Go ahead an pop all 8 bushings out at this time. As you remove each bushing, place it in a baggie or box clearly labeled with the location the bushing came from, for instance "front inner". You need to save these bushings and be able to identify them in case you have a disaster later.

Picture 1 shows the BJP clamped into the vise, I strongly encourage you to do this. Picture 2 shows the BJP, receiver, link, and plunger all aligned correctly. Picture 3 shows a close of up of the plunger hitting the metal sleeve in the bushing dead center. A lot of people let the plunger strike the bushing off center or let it "walk" across the face of the bushing as they turn the plunger. Doing so will result in dead bushings.






Once you have 4 empty links, you need to dress any aluminum links you might have. Dressing simply means finishing the fine machining process that Subaru never got around to. Basically, you're going to use wet-dry sandpaper to remove any burrs, edges, grooves, etc and to make the hole fractionally larger. Also, some of the aluminum factory links I've worked with had a bevel leading down into the hole. Once set didn't. If you're don't have the bevel, put it there. A sharp/square edge will rip bushings apart. You should spend 10-15 minutes per hole wet sanding. While this does take a lot of time, it drastically increases the likelihood of successful pressings. Just keep going until you can run your finger all around the hole and the rim on both sides without feeling anything. Once you've got all 8 holes slicked up, drop all the links in a tub of hot water like this (keep adding hot water as necessary,the idea is to get the links as hot as you can stand to hold so the holes will expand):


OK, now it's time to put a bushing into a link. I STRONGLY ENCOURAGE you to press a stock bushing into a link and then back out again several times for practice. No one ever seems to believe how well aligned everything needs to be before they find out themselves the hard way. I destroyed the first and third bushings I pressed, and have now had 24 flawless pressings since. EXPERIMENT ON A STOCK BUSHING!

Take your first bushing, I recommend a outer because you have twice as many of them (more mistakes before you can't walk it back). While the links are in hot water, grease up the bushing. You should wear gloves for this as you're going to get messy. Lay a bead of grease down one index finger and roll the bushing against it to heavily grease the bushing. When done, the bushing should be covered with grease all around the outside and on both faces (helps the plunger function).




Once you're done greasing the bushing, have your helper (and you will need one for this), grab the link from the hot water, verify that the end you're about to work with is as hot as possible, and then dry the link off and bring it to you. You then should verify that your assistant has brought you the link and handed you the end that actually corresponds to the bushing you've greased up. Having to remove and reinstall a bushing in the correct place is a waste of time and increases the likelihood of damaging a bushing. Use the remaining mess of grease on your finger to grease the inside of the link. Place the link against the anvil of the BJP, place the bushing against the link, then tighten the plunger to the point that everything will hold itself in place. At this point STOP. Is everything PERFECTLY lined up? Is everything PERFECTLY square? Is everything PERFECTLY coaxial? Is the plunger PERFECTLY centered on the face of the bushing? If ANYTHING is even SLIGHTLY off, loosen the press and try again. Once you're confident everything is right, tighten the BJP until the dust boot ("ears") of the bushing being to fold back from the pressure. STOP. Again verify that EVERYTHING is PERFECT. The dust boot should be evenly folded back all the way around. The bushing should be perfectly square to the link on all axes. If the bushing is even slightly crooked, the link will rip the bushing apart as you try to press it in. If everything is perfectly aligned, continue pressing the bushing approximately 1/2 way into the link. If at any point you see the bushing begin to get crooked STOP. Use the press to completely remove the bushing from the link and start over. The most common reason a bushing that was initially properly aligned will become crooked is that the plunger has "walked" across the face of the bushing and is no longer centered. The first picture shows everything lined up in the BJP with minimal pressure on it, this is the first time you verify perfect alignment. The second picture shows the bushing centered in the link and the plunger hitting the bushing dead center. The third picture shows the dust boot on the bushing beginning to fold back; this is your last chance to make the alignment perfect without having to press the bushing back out of the link.






Once the bushing is about half way into the link, you will need to add the receiver to the back side of the link to give the bushing some breathing room. You can actually put the receiver in there to begin with, but I find that that makes one too many pieces to get lined up right at the beginning before the bushing is stuck in the link. So, once the bushing is half way in, back off the pressure on the BJP and spin the plunger open. Place the receiver against the anvil of the BJP. Place the link against the receiver, making sure that it's centered so that the bushing can pass into the receiver. Tighten the plunger down against the face of the bushing, make sure everything is perfectly aligned, and continue to press in the bushing. The following picutre shows how the setup should look once you've added the receiver at the half way point.


Once everything is aligned, you'll need to press the bushing slightly past center and out the other side (hence the need for the receiver). By over-centering the bushing, you're giving the dust boot that you folded back against the bushing initially a chance to pop out the other side and become free. When the dust boot pops free, you'll hear the bushing "crack" out the other side of the link. It won't be a single crack, so don't stop at the first sound. Once you've started cracking, then gone about 1/2 turn without any more noise, you can be pretty confident that the dust boot is free. Once the boot is free, loosen the BJP and flip the link over and press the bushing back towards center. The first picture shows how the trailing face of the bushing will be dimpled into the link because you pressed past center to pop the boot free. Picture 2 shows about how far you'll need to over center. Picture 3 shows the link flipped around so you can press the bushing back towards center.






You'll need to drive the center of the bushing SLIGHTLY past center again because the bushing will "bounce" back once you release the pressure on it. The first couple of times, you almost certainly won't get it just right and your bushing will still be off center. Don't worry about it, just flip the link over and press back towards center as many times as it takes to get it lined up dead in the center. When done, your bushing and link should look roughly like this:


Congratulations! You've installed a bushing. If you're smart and listening to me, pop it right back out and put it right back in. Practicing with a stock bushing will make it much less likely that you'll destroy an expensive Group N bushing. Once you're confident in your pressing-fu, install all 8 Group N bushings, making sure you're putting the right ones in the right places! After they're all in, proceed to the re-assembly instructions.

Phew. After typing all this, it's tempting to pull a Subaru and say "install in reverse order of disassembly". Because you did just recently take all this apart, I'm not going to be as thorough in the reassembly instructions, but I am going to hit the high points and some of the gotchas.

To reinstall, start with the inboard end of the rear lateral link. This is the eccentric bolt used to control toe. On the majority of the cars I've done this to, the suspension pick up point has been VERY tight on the lateral link. It has required some... persuasion... to get it to fit again. Anyway, force the link up into the pick up point and work the bolt through the link. At this point, make sure you can swing the link over into it's final position. I once didn't have the car high enough and found that I had trapped the link on the the wrong side of the floor. Doh. Place the eccentric washer on to the bolt and make sure it seats properly into the recess on the subframe. Then place the thick circular washer and nut onto the bolt and hand tighten. Don't use tools yet. Use your fingers (or a socket if you have to) to spin the bolt around until your witness marks line up. DON'T FORGET TO DO THIS!

Reinstalling the front link is a little trickier. PLACE THE OUTBOARD END OF THE LINK ON TOP OF THE TRAILING LINK. If you have the outboard end of the lateral link below the trailing link and bolt the inboard end of the lateral link to the chassis, you will NOT be able to swing the lateral link up into position because it will hit the trailing link. Force the link up into the pick up point just like you did the rear one. Now, get your floor jack and lift the knuckle so that you can get the bolt into the inboard end of the front lateral link. Install the funky washer and the nut, hand tighten, and drop the knuckle back to full droop.

Before re-installing the big long bolt through the knuckle, coat it HEAVILY in AS. Also coat the insides of the bushings and knuckle itself as well as possible with AS. A small disposable shop paint brush can be a help here. Once covered in AS, slide the big long bolt into the rear lateral link, then knuckle, the front lateral link, then place the washer and nut onto it. Hand tighten the nut, no tools yet.

Rubber has a property called hysteresis, which basically means if you deform it, it likes to bounce back to where it was. The importance of this in suspension is that you always need to tighten the bolts for bushings AT RIDE HEIGHT! Use a floor jack to raise the knuckle up to ride height, then begin torquing down the bolts. Both of the inner bolts are torqued to 74lb-ft. You'll need a crow's foot to do this and you'll have to torque the front one from the head side of the bolt (which is less than ideal). Make sure your witness marks are lined up! Torque the big long bolt to 103lb-ft. Once everything is torqued, drop the knuckle back to full droop and re-install the ABS sensor wire and parking brake cable brackets. Both of those little bolts get torqued to 24lb-ft. Reinstall the wheels, torquing the lug nuts to between 68 and 74 lb-ft ( I use 70, making all 5 nuts exactly even is WAY WAY more important than the exact value). Lower the car back onto the ground. Re-attach the endlinks to the rear lateral links, torquing the bolts to 33.2lb-ft (if you've aftermarket links, follow the manufacturer's guidelines).

Go for a gentle drive, feeling and listening for anything amiss. Enjoy!

[snorky]

Excellent write up, sir! My hat is off to you and I will surely use this write up for my Group N bushing install in the near near future.

[stretch]

I just realized only one person had thanked you for this write-up. Let me be the second! The taco link picture is hysterical, too.

I'll reiterate that those lateral link bushings are very, very soft. Lots of people have called the car's bushings- generally speaking- overly soft, and often I disagree. Some bushings are nice to have soft for NVH purposes. However, these lateral link bushings really are much too soft, especially the rear one which must translate forces to the sway bar. I suspect 50% of the gain in feel for the rear could be from replacing just the outside bushings on the rear link simply so the sway bar works better.

Since I didn't see them posted, here's what I have as the required parts (quantities are total for both sides):

ST2022044020: outer bushings for front and rear links (qty: 4)
ST2022044030: inner bushing for FRONT link (qty: 2)
ST2022044040: inner bushing for REAR link (qty: 2)

[williaty]

Originally Posted by stretch

You need 4 of theseST2022044020 rear lateral link bushings (outer link, front and rear)
You need 2 of theseST2022044040 rear lateral link bushings (rear link inner bushing)
You need 2 of theseST2022044030 rear lateral link bushings (front link inner bushing)

Just added quantities.

[Mustangkilla]

Out of curiosity.. Can those peertty 05+ lateral links be swapped into an 04 with little or no modifications?

[williaty]

Originally Posted by Mustangkilla

Out of curiosity.. Can those peertty 05+ lateral links be swapped into an 04 with little no no modifications?

So long as they're from the same chassis (STi, sedan, wagon), they're a direct bolt on, no modification necessary.

[stretch]

What is the correct size for the receiver for the bushing? It looks like you had to scrounge for a part, but once I have my links off the car, I won't exactly be able to drive to the store and do that.

For others, this is the cheapest BJP I found:
Harbor Freight Tools - Quality Tools at the Lowest Prices

[williaty]

The Harbor Freight BJP occasionally goes on sale for $40. However, the cost effective way to do it is to just borrow it from an autoparts store.

Stretch, as far as the receiver ID, I think it was in the 2.25 neighborhood. I've passed those bits on to someone else doing the swap. However, when you get your Group Ns, just take a bushing over to Lowes and go to the plumbing section. You want to get a threaded coupler like that that the bushing will JUST fit into without having to fold over the dust boots.

You know, I didn't realise it when I wrote this up, but these instructions leave out a detail if you're not doing it on a STi. The cheaper cars have different rear trailing links that require a slightly different receiver.