bwalton Posted December 2, 2006 Share Posted December 2, 2006 Last year I brought my 05 OBXT into the dealer with an alignment readout from Big O that said my right wheel caster was +5.0 and the left wheel was at +5.9. This 7/8 degree spread on the caster explained my right hand pull as well as out of tolerance. The dealers machine caster read before the touched my car was L=+5.6 and R=+5.1 a 0.5 spread. The dealer claimed that they shifted the front sub-frame, which yielded a 0.1 degree spread between the right and left caster. The alignment readout that they furnished me stated that all of the toe-ins were set to 0, the caster was set to +5.4 degrees on the left and +5.3 degrees on the right and the front camber was reading +0.7 degrees on the right and +0.6 degrees on the right. Both of the left and right rear wheels camber was reading 0. Well after about a week of driving I brought the car back into the dealer with the same complaint—the car still pulls hard to the right. They put it back on the alignment rack and said that all the reading were the same and claimed that they called Subaru who said that these cars pull and that there was nothing they could do about it. Last week (one year later) I brought my car into Les Schwab for an alignment because I had accelerated wear on my One year old Falken ZE-512 tires, which had full tread on the inside shoulder down to a small amount of tread on the outside shoulders on both front tires. The alignment tech hooked the wheels up the newer hunter machine with the following readings: Caster L=5.9, R=4.9, Front Camber L=0.6, R=0.2 and both of the rear toes pointing to the left. He loosened up the rear front control arm bolts and put a come-along on each control arm and tried to shift the caster without success. I told him that the dealer shifted the sub-frame last year and he said that none of the sub-frame or rear control arm bolts had any marks on them. He also showed me that bumping the wheel sensors can change the readings significantly. I brought the car back to the dealer and let them know that again the caster had a 1 degree spread, which is out of tolerance. They claimed that their machine gets calibrated monthly and tire shops are not required to calibrate their machines and hence the discrepancy between the readings. The dealer’s alignment machine read that both of my front wheels were toed out and both of rear wheels were toed-in. The left caster read +5.4 and the right equaled +5.2. The front camber readings were +0.6 on the left and +0.2 for the right. All of the toes were out of specification by as much as 0.12 degrees or 1/16”. All of the toes were reset to 0 and they explained that the smaller +0.2 degree camber on the right front wheel was set last year after I came in for my second visit to counter the uneven caster. Case and point of this story, the sub-frame and rear control arms can not be adjusted. The mounting holes for the sub-frame and the rear control arms may be oversized by 1/16”, which will yield a maximum of 1/8”or 0.1 degree adjustment if one side is pushed forward and the other side is shifted back. Also these alignment machines measure caster indirectly as well as estimate where the true center of the car is. This imaginary centerline drives the toe-in and thrust angle measurements, which as you see varies between each alignment rig. So my real caster reading is in the range of 0.2 to 1.0 degree of split, which is causing my right hand pull. Has anybody driven on the Fulcrum Superpro LCA bushings or adjustable strut hats for a year with out any problems? Link to comment Share on other sites More sharing options...
fweasel Posted December 2, 2006 Share Posted December 2, 2006 Has anybody driven on the Fulcrum Superpro LCA bushings or adjustable strut hats for a year with out any problems? I think they were only discovered as a Legacy application about 1.5 months ago. ignore him, he'll go away. Link to comment Share on other sites More sharing options...
NSFW Posted December 2, 2006 Share Posted December 2, 2006 I need a sanity check here... either I don't understand alignment or your dealer doesn't. Or maybe we're both on crack. Somebody please help. I don't see how caster would cause pull. Caster refers to the angle of the steering axis, it basically adds camber as you turn tighter. So, if you're going straight ahead, caster is adding zero camber, regardless of what your caster angle is. I also don't see how shifting the subframe would correct a caster difference. Wouldn't you have to twist the subframe to affect caster differently on each side? Did you notice a change in the pull after visiting Les Schwab? Or after visiting the dealership the second time and getting the toe-in adjusted? Link to comment Share on other sites More sharing options...
Deer Killer Posted December 2, 2006 Share Posted December 2, 2006 caster does cause pull.. If you can't fix it by shifting the subframe then that means something is out of spec, either the chassis or the subframe. The subframe can be replaced.. Maybe the car was in an accident.. Link to comment Share on other sites More sharing options...
bugblatterbeast Posted December 2, 2006 Share Posted December 2, 2006 I need a sanity check here... either I don't understand alignment or your dealer doesn't. Or maybe we're both on crack. Somebody please help. I don't see how caster would cause pull. Caster refers to the angle of the steering axis, it basically adds camber as you turn tighter. So, if you're going straight ahead, caster is adding zero camber, regardless of what your caster angle is. I also don't see how shifting the subframe would correct a caster difference. Wouldn't you have to twist the subframe to affect caster differently on each side? Did you notice a change in the pull after visiting Les Schwab? Or after visiting the dealership the second time and getting the toe-in adjusted? cross-caster causes a pull by making the centering forces on the front wheels uneven. when a wheel is turned, the car is lifted slightly because of the tilt in the steering axis. the car naturally wants to sit at the lowest position. if there is cross-caster, the lowest centering point is off center. when you shift the subframe you move the lower pivot points and shift the tilt of the steering axis. Link to comment Share on other sites More sharing options...
NSFW Posted December 2, 2006 Share Posted December 2, 2006 Interesting, thanks. Link to comment Share on other sites More sharing options...
captainmorgan Posted December 2, 2006 Share Posted December 2, 2006 bwalton, I read your first post on this way back when and used it as a start to get my cross caster fixed. I had my front caster corrected from 6.3/5.3 to 5.5/5.4 over the course of the year (had three alignments two on hunter equipment, one by hand). I can now safely say that the car tracks straight like it never has before. The superpro bushings will be going in later next year (sitting on the desk right now) and we'll see how that goes. Link to comment Share on other sites More sharing options...
bwalton Posted December 2, 2006 Author Share Posted December 2, 2006 capainmorgan, 1) What was your caster reading on your two subsequent alignments after your sub-frame was shifted? Shifting your sub-frame decreased your left caster by 0.8 degrees. When the dealer first shifted my sub-frame the amount of movement equaled 0.5 degrees (5.6/5.1 to 5.4/5.3). After one year the caster readings on the dealer's machine was still within 0.1 degree 5.4/5.2. 2) Did your toe-in measurements move from one alignment to the next like mine? I don't know which of the three hunter machines is accurate, two of the rigs from the tire stores say I have a 1 degree cross caster and the dealer's machine reads that my cross caster is within 0.2 degrees. My wife had her steering rack replaced last year in her 05 OB 2.5i and the initial reading on the dealers machine with the left and right toed outward was a cross caster of 0.6 degrees. With the toes set to zero her cross caster evened out to within 0.1 degree. 3) How did you perform your own alignment? Did you find the true centerline of the chassis and snap parallel string lines on each side of your car then set the toes from the 2-string/base lines? 4) What is your front camber reading? My wife's car is set to -0.2/-0.1 and her car does not have a pulling issue. My car's camber is set to +0.6/+0.2 and has a pulling issue. None of the alignment shops will adjust my camber down to zero or less, which is within Subaru's tolerance. Link to comment Share on other sites More sharing options...
Guest Posted December 2, 2006 Share Posted December 2, 2006 None of the alignment shops will adjust my camber down to zero or less, which is within Subaru's tolerance. Why not negative camber? Link to comment Share on other sites More sharing options...
rougeben83 Posted December 2, 2006 Share Posted December 2, 2006 A lot of shops these days rely too much on the machines and "within tolerance" excuses to get away with improper alignment. For the most part, they can get away with it since it won't give any obvious signs to the driver (like the unever wear and pull to one direction), but on a small group of cars even if the alignment is "within specs" it won't help. My suggestion is to go to a shop that does a lot of alignments for competition/race vehicles; ask any local serious auto-x'er in your area and they should be able to recommend a place. These places tend to be more anal about alignments and some even do it the old fashion way (by hand). It'll cost more but you'll be guaranteed that your alignment has been performed with a greater degree of accuracy, if not for the sole reason that they will also put any amount of camber that you want on your car. Link to comment Share on other sites More sharing options...
captainmorgan Posted December 2, 2006 Share Posted December 2, 2006 I think the most important thing is not the actual numbers but the delta. All the readings that I've had, have ben consistant on the difference in cross caster. I didn't do it be hand. There is an alignment shop run by a guy thats been doing alignments for a million years. Hes very good. Its funny, he doesnt have a computer anywhere in his shop, and all payments are check or cash. He comes highly recommended by every one I know in motorsports. The shop I go to (the one with Hunter equipment) is run by a group of guys that are very serious about being the best most reliable shop in the area. They are also heavily into racing (they sponsor all the SCCA and WIA autox events). Most of the techs that work there, come from a background where they learned what the numbers of the alignment mean, how to change them, and how to interpert what the computer reads back. I trust what they tell me. Just checking the FSA and it says that stock an OB should be +0.4. I dont htink that subarus are very good when setup with positive camber, they get all twitchy and wandery. Also, check the build date of your OBXT and make sure that your pull isnt being caused by a bad wheel bearing (I went through both rears). Link to comment Share on other sites More sharing options...
bwalton Posted December 3, 2006 Author Share Posted December 3, 2006 I asked the dearer to check for cracked buchings on front control arms and bad wheel bearings. What do bad wheel bearings feel like and or sound like? Link to comment Share on other sites More sharing options...
captainmorgan Posted December 4, 2006 Share Posted December 4, 2006 It sounds like a jet engine just outside your car. Its loud as hell. It changes with speed. Read this. Link to comment Share on other sites More sharing options...
robinasu Posted January 1, 2007 Share Posted January 1, 2007 My LGT came off the lot with a cross caster problem - pretty sure the dealer inflated the tires during the test drive or hit a curb from then to pickup. It's very irritating that my caster is off side to side by a solid 1.0 degree. I have the print outs. I just inflated the right tires 2 lbs more than the left. It works, but still not as good as having a clean car. Any ideas to correct? Dealers are no help. I'll take a measuring tape to the front suspension one of these days, or just trade it in when I start my new job. Good car.. wish I had waited for a '06. I most likely won't buy a subaru again due to this and the hesitation issue. The hesitation is a joke - no reason a 2005 car with electronic control should hesitate - turbo or not. Also, the auto climate control is bad. I would rather have manual controls. When the outside temp is approx equal to the interior temp the ACC over and undershoots the cabin setpoint - too much derivative and/or not enough integral in the control loop. I ramble.. take care. Link to comment Share on other sites More sharing options...
Th3Franz Posted January 1, 2007 Share Posted January 1, 2007 There's a difference in caster between left and right in the front on my car. My car drives perfectly straight since I have had it aligned a few times to try out different alignments for handling. I can't recall the exact difference in caster, but it was enough for me to notice it on the last printout. -Franz The end of a Legacy http://www.youtube.com/th3franz Link to comment Share on other sites More sharing options...
bugblatterbeast Posted January 1, 2007 Share Posted January 1, 2007 I've actually been thinking about this issue for a bit as I too have some cross caster. So far I've been toying with two ideas 1) Offset LCA bushings. I like this idea because it will give me a chance to increase the caster and get rid of the cross caster. What I don't like about this approach is the need to press the bushings out and in each time I want to make an adjustment. I have access to a press but it just seems like too much work. Maybe when I get more annoyed with the drift I'll deal with it. 2) Adjusting the rear thrust angle so the effective cross caster is less. I'm not sure if this will work yet but my gut feel is that it will. If the rear thrust line is shifted slightly in the direction of the pull, I'm hoping the projection of each steering axis tilt on the plane defined by the new thrust line (rather than the geometric centerline) will have equal for and aft tilt. The car will dog track by a small amount (less than a degree probably) but the pull should vanish. The advantage of this method is it allows lots of tweaking by just adjusting the rear toe eccentrics. I just need to prove to myself that this will work (atleast on paper) before I try it Link to comment Share on other sites More sharing options...
bugblatterbeast Posted January 1, 2007 Share Posted January 1, 2007 I'll take a measuring tape to the front suspension one of these days, or just trade it in when I start my new job. . try a level gauge + a magnetic hub clamp. you can make your own slip plates with a few sheets of metal and some grease. caster measurements are easier to make by observing camber change during steering than by measuring control arm lengths. Link to comment Share on other sites More sharing options...
robinasu Posted January 1, 2007 Share Posted January 1, 2007 I've actually been thinking about this issue for a bit as I too have some cross caster. So far I've been toying with two ideas 1) Offset LCA bushings. I like this idea because it will give me a chance to increase the caster and get rid of the cross caster. What I don't like about this approach is the need to press the bushings out and in each time I want to make an adjustment. I have access to a press but it just seems like too much work. Maybe when I get more annoyed with the drift I'll deal with it. 2) Adjusting the rear thrust angle so the effective cross caster is less. I'm not sure if this will work yet but my gut feel is that it will. If the rear thrust line is shifted slightly in the direction of the pull, I'm hoping the projection of each steering axis tilt on the plane defined by the new thrust line (rather than the geometric centerline) will have equal for and aft tilt. The car will dog track by a small amount (less than a degree probably) but the pull should vanish. The advantage of this method is it allows lots of tweaking by just adjusting the rear toe eccentrics. I just need to prove to myself that this will work (atleast on paper) before I try it Yes, the bushing option is a pain in the ass. I see what you bean about adjusting the rear. I think my dealer tried that with no solution since the car was on the rack three times. I can tell they removed a lot of bolts when the subaru engineer came to look at the car, to no avail. My car pulls decently to the right, enough to be constantly correcting the wheel. Overinflating the right tires helps. The dealer tried everything to get rid of me.. even saying it was a "tire pull". The bottom line is there is 1 degree of cross caster and they are not willing to be of anymore help. I saw some cool adjustable upper strut mounts a while back. You could adjust caster andcamber in pretty small increments pretty easily. The company made/makes billet pedals and honeycomb cat downpipes.. what was that name.. Link to comment Share on other sites More sharing options...
bugblatterbeast Posted January 2, 2007 Share Posted January 2, 2007 there is one more option, which I'm not partial to. you could have the frame pulled. to get rid of 1 degree of cross-caster I'd wager you'd need to move the LCA mounting point by ~0.1" on each side of the car. a competent body shop should be able to bend the rear LCA mounting pin for you. what type of alignment rack does your dealer use? I've run into at least one shop where the rack was the cause of my problems. I couldn't get the car to dial in correctly so I aligned it on the street instead. it turned out that the shop's slip plates were binding somewhat and causing weird readings. I've since stopped using alignment racks for all but the most troublesome problems. I think you might be thinking of ingalls. they don't make anything for us last I checked.... Link to comment Share on other sites More sharing options...
captainmorgan Posted January 2, 2007 Share Posted January 2, 2007 Go to a reputable alignment shop. The guys I went to have been doing this for a thousand years. Most likely wha tthey'll do is loosen the sub frame and some of the mounts on the control arms, then anchor a point on something rigid and use a come-along and pull it until it slides into position. it's not rocket scinece but if they dont measure well, and dont know what they are doing, it wont help any. I honestly dont think that the bushings are a good way to go. You aren't correcting the root problem, just correcting the symptoms. Get the cross caster issue fixed, then get the bushings installed. Link to comment Share on other sites More sharing options...
bwalton Posted January 2, 2007 Author Share Posted January 2, 2007 Happy New Years! Well after two years of frustration and out of pocket expenses for two new sets of tires and four alignments here is what I have learned: 1) Alignment machines are not very accurate or precise. Case and point, the accuracy between the toe-in, camber and caster readings between two different machines varies. For example, recently a tire shop put my car on their alignment rig and said that my cross caster had a 1.1 degree spread, the front wheel toes were approximately 0 while the rear toes were both pointing to the right to counter the bad caster. One week later the Subaru dealer said that the cross caster has a 0.2 or 0.3 degree spread, the front wheels were toed in towards each other (out of spec.) and the rear wheels were toed outward (out of spec.) and the FR camber was set to +0.2 and the FL camber was set to +0.6. 2) Precision-compare the Subaru Dealers most recent readings above with last years readings, which had all of the toes zeroed out, a cross caster spread of 0.1 and camber of 0.6 for the left and 0.5 for the right. Conclusion: My car seems to pull less than it has in two years because, in my opinion, the dealerfinally set the toe correctly on all four wheels.Now if I can find an alignment shop that will adjust my camber from positive values down to negative settings. Try to find a competent alignment shop and technician who will tweak your alignment settings without charging you each time they set your car on the machine. Link to comment Share on other sites More sharing options...
Guest Posted January 2, 2007 Share Posted January 2, 2007 Try Firestone. Liftime alignment for <$150 FTW> If you find decent place, they can actually do acceptable job, especially if you tip tech like $20, they will keep tweaking all you want :-) Link to comment Share on other sites More sharing options...
bugblatterbeast Posted January 2, 2007 Share Posted January 2, 2007 I got off my lazy ass and BFHed the subframe. The cross caster is gone After shifting things around I was somewhat surprised by how tweaky our cars are. On the Hondas and Acuras I've played with, the car won't pull as long as caster and camber are right. The Subaru wouldn't stop pulling till I had caster camber and toe on the money. The sweet spot was much smaller than I expected. It is weird, on SLA suspensions I can have toe out to lunch and the car won't pull (wheel is off center but the car still tracks). With the Subaru, the smallest bit of toe error sends the car all over the road. Tweaking is the key. The laser pointer + sheet of drywall method will get you close but the final adjustment is best left to the seat of the pants. Link to comment Share on other sites More sharing options...
red_suby Posted August 23, 2009 Share Posted August 23, 2009 Go to a reputable alignment shop. The guys I went to have been doing this for a thousand years. Most likely wha tthey'll do is loosen the sub frame and some of the mounts on the control arms, then anchor a point on something rigid and use a come-along and pull it until it slides into position. it's not rocket scinece but if they dont measure well, and dont know what they are doing, it wont help any. I honestly dont think that the bushings are a good way to go. You aren't correcting the root problem, just correcting the symptoms. Get the cross caster issue fixed, then get the bushings installed. Could you share that shop information? My car is pulling to the right because of around 1/2 degree Cross caster. My local tire shop can't fix this cross caster issue and they say it is not adjustable. Following are my alignment readings Front Camber (L,R) -0.5, -0.7 Caster (L,R) 5.2, 4.8 Toe (L,R) 0.01, 0.02 SAI (L,R) 14.3, 14.3 Cross camber 0.2 Cross Caster 0.4 Cross SAI 0.0 Total Toe 0.02 Rear Camber (L,R) -0.9, -0.9 Toe (L,R) 0.06, 0.06 Cross camber 0.0 Total Toe 0.12 Link to comment Share on other sites More sharing options...
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