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Old 01-02-2008, 10:03 PM   #1
InsatiableAmos
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Default '04 STI-swapped GC steering rack problem

Hey guys - i recently got my STI-swapped GC up and running, but i'm having trouble getting the steering to work smoothly. The steering setup I've currently got in the car is:

-2004 USDM STI Steering rack installed in
-JDM GC8 STI Front Crossmember coupled to the
-2004 USDM Steering column using a
-Shortened (chopped and re-welded) 2004 USDM STI U-Joint Linkage

The problem is that the steering is "lumpy." The amount of effort to turn the wheel from lock to lock pulses about every 1/4 turn because:

The stem on the STI steering rack where the U-Joint connects is significantly (about 1.5 inches) longer than the old GC steering rack. This means that the U-Joint between the steering rack and the steering column makes almost a 90 degree bend when fully connected.

Any ideas how to:

-Shorten the STI Steering rack stem and extend the splines further down the shaft so that the bend angle of the U-Joint decreases? or
-Lengthen the steering column shaft (including splines) so that the bend angle of the U-Joint is decreased? or
-Knows of an U-Joint that has wider coupling pieces so it can smoothly handle tigher bends and still have the same spline size/pattern? (i'm thinking maybe the Legacies?) or
-Knows of a STI-Quality Steering rack with 2004 USDM-STI-compatible splines and a shorter stem?


Any and all help is hugely appreciated! At the very least, posting pictures of steering racks and U-Joints i don't have would help! If you do, please be sure to post what model and year of the car it's from as well...

Thanks.
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Old 01-03-2008, 12:56 AM   #2
ghostdriver
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are you sure all the air is out of the power steering system and that the belt is properly tensioned?

not sure why you used the jdm crossmember... you might just wanna pick up a USDM one and put an unmodified u-joint on.
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Old 01-03-2008, 01:38 AM   #3
scobaru
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he needs the modifyed U joint on and the crossmemeber isn't the problem. I'm running a jdm crossmemeber with a rev-labs wrx rack and modifyed U joint. I'm still using the RS steering column. A few thoughts come to mind

1. what pump are you using? the Sti/wrx pump I believe is bigger can flow more for a shorter rack.
2. the U joint might not be on correctly. the U joint has to slide on pretty far down and pretty far up the splines on the column. it matters where the bolt threads though and that its in the correct position. I had a huge issue like this for a few weeks and I took my modified joint out and threw it in the correct way where the flat spot on the spline meets with the bolt on the joint. once I did that it was a lot smoother.

if u have a pump that can't keep up it could cause similar problems. I'm sure theres others that could chime in who's done the same swap since my story is a tad different than urs.
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Old 01-03-2008, 02:30 AM   #4
InsatiableAmos
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I need the JDM crossmember to fit the turbo exhaust plumbing and not shim my control arms...the position of the steering rack shouldn't change from crossmember to crossmember.

I'm also pretty sure that's it's NOTHING to do with the pump or hydraulics of the PS system. I'm using the USDM STI pump and lines, and the car has been driven for almost 250 miles (so it's had plenty of time to work the PS fluid through the system).

When i disconnect the U-Joint entirely, the wheels turn back and forth smoothly when i push them. The steering column also goes through it's full rotation without incident. When i hook the U-Joint up, i can feel the lumpyness both when pushing the wheels left and right by hand (with the car jacked up and turned off) as well as when turning the wheel. It is just pronounced further once there's resistance on the tires.

Scobaru: Just out of curiosity...how is your U-Joint modified? I actually had to shorten the GD U-Joint to fit the bolts through where the flat spots are on the splines, so i'm pretty sure the U-Joint's on far enough at both ends. Can you take pics of the rack stem and your modified U-Joint, or at least describe them? I may have to go aftermarket with this.
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Old 01-03-2008, 02:35 PM   #5
ghostdriver
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you do not need the jdm one. i have the usdm 04 sti crossmember and all of the steering stuff and the sti steering column and the unmodified u-joint in my 1998 L. i put the sti control arms in too and everything fits just fine and once i got the right belt and tensioned it enough i no longer had any bumpy steering issues.
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Old 01-03-2008, 04:02 PM   #6
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*sigh*

Ghostdriver: You had to use the STI control arms with your STI crossmember, didn't you? Then you had to roll your fenders to prevent rub probably because the STI control arms are significantly wider-track than the stock GC running gear, huh? The crossmember and control arms on my donor STI were thrashed from the accident it was in, so i'd have to find and pay for new ones if that was the route i wanted to take...in addition, i didn't want to deal with wheel/tire/rubbing issues because of the wider track.

As far as i know, the position of the steering rack in the crossmember doesn't change from JDM STI to USDM '04 STI...the only difference is the space between the column and the rack stem because of GD versus GC chassis size differences. In otherwards, i'd have the same problems if i used the GD front crossmember in my setup, but i'll drag it out of the closet just to make sure.

I can also pretty much guarantee that it's not an issue with the power steering pump, pulley, belt, or pressure. The lumpiness is even present WHEN THE CAR IS NOT RUNNING. The column and rack move freely on their own when the U-Joint is removed, but as soon as it's added back into the mix, the resistance returns.
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Old 01-04-2008, 04:54 AM   #7
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no fender rolling and even though it was a tight fit all the steering stuff still fit right. sorry i didnt realize the stuff was destroyed in the accident. i keep trying to remember how we made it all fit together right but i just cant seem to do it. good luck.
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Old 01-04-2008, 08:14 AM   #8
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Quote:
Originally Posted by InsatiableAmos View Post
The steering setup I've currently got in the car is:

-2004 USDM STI Steering rack installed in
-JDM GC8 STI Front Crossmember coupled to the
-2004 USDM Steering column using a
-Shortened (chopped and re-welded) 2004 USDM STI U-Joint Linkage
.
Put a stock STi U-Joint in, and try it.
I've done and seen this exact setup, and don't remember any issue just dropping in the respective pieces unmodified.
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Old 01-04-2008, 08:26 AM   #9
garface
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Wouldn't an STi or GD steering column fix this? I think I have one laying around somewhere that I can sell you. PM me if you decide you want it.
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Old 01-04-2008, 08:24 PM   #10
InsatiableAmos
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Quote:
Originally Posted by kaos200 View Post
Put a stock STi U-Joint in, and try it.
I've done and seen this exact setup, and don't remember any issue just dropping in the respective pieces unmodified.
The STI U-Joint was stock when i first put everything together... It didn't work right, so i modified it in such a way that i thought it would help - it didn't.



Quote:
Originally Posted by garface View Post
Wouldn't an STi or GD steering column fix this? I think I have one laying around somewhere that I can sell you. PM me if you decide you want it.

As stated in the first post, and the post directly above yours, i already have and am using the stock steering column from the 2004 STI. It's easy to see why NOT using this would cause problems, as the stem on the GD column is shorter, and the spline size/pattern is different.
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Old 01-05-2008, 12:29 AM   #11
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my modifyed joint's length is inbetween both sizes since I know what ur talking about in difference in size. I modded mine since I'm using a GC column with a GD rack. your joint must be binding I'm not really sure what u could do...
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Old 01-25-2008, 06:15 PM   #12
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I have a wrx crossmember, wrx control arms and gc8 pinks, prodrives, and group N's. Here is what I did to deal with the rack column compatibilityissue: http://forums.nasioc.com/forums/show....php?t=1335063
Now since I got the car aligned the steering appears to have memory, as in if I make a hard right the car pulls to the right when I return the wheel to straight. I also had similar issue in roughness in the feel before the alignment which I guessed was the pump or air in the system. I was told by a knowledgeable friend it may be alignment, probably castor issue. Maybe its the control arms changing the suspension geometry?
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Old 01-25-2008, 08:16 PM   #13
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if you dont have the pump that was made for the rack then it wont work.
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Old 01-25-2008, 08:17 PM   #14
NICO TURBINE
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if you dont have the stock pump that was made for the stock rack then it wont work.
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Old 01-26-2008, 02:47 AM   #15
InsatiableAmos
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MMastro: Thanks for a totally new perspective on this whole shebang Hadn't really thought about pulling the rack apart really.

Your steering memory issue could be from the increased camber up front (because your track widened without the strut top mounting points widening). Increased castor always helps the steering re-center itself, there was an article about the team orange drift guys adding castor because RWD cars don't re-center their steering as well as AWD stuff. An anti-lift kit from the likes of Perrin or Whiteline can help this, as well as camber/castor plates for the strut tops.

Nico: I appreciate the attempt at helping, but i ruled out the pump from the very beginning of this whole thread because i have stock 2004 STI everything; pump, rack, column, you name it. I also noted this after several OTHER people mentioned the pump as a possible issue:

Quote:
Originally Posted by InsatiableAmos View Post
I can also pretty much guarantee that it's not an issue with the power steering pump, pulley, belt, or pressure. The lumpiness is even present WHEN THE CAR IS NOT RUNNING. The column and rack move freely on their own when the U-Joint is removed, but as soon as it's added back into the mix, the resistance returns.
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Old 01-27-2008, 12:02 PM   #16
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I forgot to mention I do have a ALK kit. Also like I said I don't remember it having the memory before the alignment which put me all within specs they had for the 2.5 RS. My feel before the alignment is more along the lines of what you originally described as an uneveness in the feel throughout the range of turning. Are you aligned yet?

I'm considering adjustable top hats now to try and solve this, problem is the only ones I can find that have castor and camber are Noltecs maybe the Whitelines. The Noltecs are sold out at Oakos the only place I new that carried them and from talking with them previously they may not get more because they greatly increased pricing or something. I'll post my alignment specs once I have them in front of me again.
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Old 01-28-2008, 08:20 PM   #17
InsatiableAmos
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MMastro: I am aligned (although badly). The car doesn't have "memory" really though, and it definitely tracks WAY better than it did before i got it aligned

As far as finding Caster/Camber plates...i've heard that if you pick up Castor plates for '02-'03 WRX and reverse the sides (left plate on right side, right plate on left side) on a GC chassis, you'll get ONLY castor plates! I've never seen it first hand, but i've heard it from a few sources i trust, and if you're not looking for huge camber it should work just fine for you.
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Old 01-29-2008, 10:17 AM   #18
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I would describe my the feel of mine quite similar to your post #4 before my alignment. Are you sure your steering column is in the socket in the fire wall? Maybe that could cause some roughness... mine had popped out at some point during the swap, but I realised before I put the dash back in.

Update:
Figured out what my problem was... when I got my used struts, springs, tophats there no conical washers so I didn't have them in... the front top hats got smoked because of it or were so already. This thread describes the issue more:
http://forums.nasioc.com/forums/show...ghlight=memory

Last edited by MMastro; 02-06-2008 at 04:57 PM.
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Old 02-08-2008, 03:40 AM   #19
InsatiableAmos
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Glad you found the source of your issue, Mastro

I also at least improved on mine...played with the geometry and positioning of the steering column in the firewall hole and in relation to the steering rack. Ended up elongating the flat spot on the column shaft so i could slide the knuckle a little further up the shaft, and i made sure the column was ALL THE WAY down into the bushing.

Verdict: It's WAY better! If you're thinking hard about it when turning, you can still feel a little roughness...but i can once again take corners in both directions with only one hand! A little anti-lift-kit action, and it'll center itself even better than stock! Phew...that's pretty sweet.
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Old 11-17-2009, 04:27 PM   #20
InsatiableAmos
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Update: schwag wagon asked if i had ever resolved the issue...and i have!

I asked GST Motorsports (http://www.gstmotorsports.com) to custom fab a steering rack knuckle that mimics the stock GC knuckle perfectly, including joint angles and length. The steering-rack U-Joint is from the 2004 STi so it fits the rack, while the column-side U-Joint is from the original GC-Chassis setup, so i can use the longer GC-specific steering column. GST charged me ~$70 to create the new U-Joint (i supplied the parts), and i picked it up the same day.

In the end, my steering feel is still not perfect (though my only REAL basis for comparison is a track-prepped '95 M3), but that's probably more from my crappy suspension geometry. The steering action is about as smooth as it gets on a subaru
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Old 01-25-2011, 09:33 AM   #21
RALLY200SX
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Is there any difference between a 2002 WRX crossmember and a 2004 WRX crossmember?
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Old 01-25-2011, 03:15 PM   #22
AKGC8
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Just FYI, I had the same issue and my fix has cleared it up. A post from a week ago:

http://forums.nasioc.com/forums/show...44&postcount=3
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