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danmartinic wrote: Mon Apr 27, 2026 10:20 am
After changing a loose tie rod and ripped boot this weekend, I need to get the toe set. Bummer as I just had an alignment done not too long ago.
At this last alignment, they allowed me to come and install the bolt that locks the steering rack (I prefer this over centering the steering wheel).
After adjusting the toe, I noticed that when I loosened the bolt, the toe went "red" (out of spec). I snugged it back, and it went green.
We are talking uber-slight movement of the rack
After this, I can't imagine how all those times I used strings and rulers could have been accurate
A couple things to consider with your symptom. First is the idea that the rack (the long gear and shaft inside the tube) doesn't change length, so the centering bolt is pushing the rack to one side, but the wheels where you are measuring don't actually change unless there's play in the tie rods.
-- In my own experience, changing one of four tie rod sections is a partial fix at best. Unless they are all relatively new when you discover a torn boot, I'll make the argument for changing all four.
-- Wear in the end bushings might allow the axial position of the rack in the tube to change when centering bolt pressure changes. With the geometry of the tie rods sensitive to that, especially as most cars are sagged (or adjusted) lower, the effect is multiplied.
I've participated in some string-square emergency track alignment adjustments, and they are totally subject to how level the car is sitting and specifically the ride height and load on the wheels you are adjusting. My alignment floor is hardly level side to side, and the floor slopes to the door for drainage. Both need to be compensated before you can accurately measure alignment settings. Vinyl stick-down floor tiles are the weapon of choice for correcting small differences. They go on plywood pads for the rear (downhill) end of the car before fine-tuning with the tiles. A 72" box level from Harbor Freight is sufficient for the side to side level check. Same level on a stick of box tubing enables the front to rear checks. The front to rear is critical for caster adjustments more than the other measurements, at least for most road cars. It's a good habit to follow regardless.
For "squaring the string", a common methos is to measure forward and back from known points on the chassis at both ends. Then the same side to side, usually from some center point you've identified. Measuring from the wheel center caps works only after you've adjusted camber and caster on my car, and I need to adjust rear toe before using the wheel caps to find the strings side to side.
As interesting as that string method might be, thin-walled electrical conduit (EMT) is available in 10' lengths from a big box store, and cuts with a pipe cutter or even a hacksaw for the front and rear. Clamp or tape two together, and drill holes through both at a spacing of six inches greater than your outer rim edges are apart side to side. That puts the string 3" away from the rim edges for measuring with a pocket scale. That way at least the two sides are parallel even if the square ends up being a trapezoid. Use fine wire, like stainless safety wire, instead of string between them, two pieces cut and wrapped to the same length.
I've used more than a few different DIY measurement methods, and still consider the laser fixtures I described above as the most accurate and repeatable I've found. No cussing when I kick a jack-stand or bump a string. The quality of cheap lasers has improved dramatically in the 25 years since I assembled mine, and some more consideration of my configuration suggests that I could use a decent laser pen-pointer, so long as the bloom is small. The longest "shot" is the wheelbase distance, and so long as you read the same point in the bloom you'll be fine. I still need to get a set of higher-resolution angle gauges for measuring/calculating caster. The ones I have offer 0.1º displayed resolution, but repeatability is less than stellar. Newer versions offer 0.01º display resolution, but the fine print says it's not really that accurate. At least on camber, getting the two sides the same is perhaps more critical than the absolute numbers at least for road cars.
dr bob wrote: Mon Apr 27, 2026 5:37 pm
A couple things to consider with your symptom. First is the idea that the rack (the long gear and shaft inside the tube) doesn't change length, so the centering bolt is pushing the rack to one side, but the wheels where you are measuring don't actually change unless there's play in the tie rods.
I'm confused: if the bolt, centering itself inside the dimple on the rack, pushes the rack to one side, I would assume if there was zero play in the tie rods that the wheels would then move, no? Would any play not take up that movement instead?
The measuring device is attached to the wheels and snugging that bolt up makes a difference in toe.. enough to take it out of spec (this is on the laser rack at the alignment shop)
dr bob wrote: Mon Apr 27, 2026 5:37 pm
-- In my own experience, changing one of four tie rod sections is a partial fix at best. Unless they are all relatively new when you discover a torn boot, I'll make the argument for changing all four.
After six years of daily driving since installing the manual rack setup I got from a well known shop, everything seems pretty tight other than the one side's tie rod I discovered was loose when I switched out my winter wheels & tires. I don't see any other play. The other side's boot was torn so I had to remove the tie rod there too; I put it back as it has zero play and feels solid.
dr bob wrote: Mon Apr 27, 2026 5:37 pm
-- Wear in the end bushings might allow the axial position of the rack in the tube to change when centering bolt pressure changes. With the geometry of the tie rods sensitive to that, especially as most cars are sagged (or adjusted) lower, the effect is multiplied.
Bushings? I'm afraid I'm not sure what you're referring to. I would imagine that any wear means the wheels would not move?
As for your effort over the years on this... wow! This is very commendable... but I get quite lost reading about it all. Clearly a passion!
I have tried with some string and jack stands before but frankly, it makes more and more sense to me to just pay for the darn service.. even if it's a couple times a year due to maintenance or whatnot
Tomorrow I am taking it in to the alignment shop.. but I have to say that with my toe clearly out--the steering wheel is at aprox 45 degrees from before--the car has never tracked so solid & straight; the road crown doesn't even knock it off its path. Much better than the factory setting LOL!
The centering bolt pushes the rack to the rear of the car, inside the tube. The bushings I refer to are the ones in the ends of the tube on either side of the car. They normally hold the rack relatively concentric in the tube, but they do wear. Over time and that wear, you may eventually see leakage at the ends into the boots when the hydraulic seals no longer maintain firm contact with the rack. Note that many cheaper "rebuilds" get new end seals to attack leakage, while the worn end bushings are left in place. Easy enough to check with a dial indicator, something you might try as you see the toe readings change with the centering bolt.
Toe can change when the rack moves radially inside the worn tube end bushings, and is significantly more noticeable if the car has sagged or is lowered. The angles from the end of the rack to the tie rods are smaller. That also promotes extra radial wear at the inner tie rod and those bushings. It's tempting to replace just the outer tie rods, since that's where any play appears most obviously. But the inners wear just as fast or faster.
In the end, you want to adjust so toe is correct at driving speed. Available movements that affect toe include ball joint wear, inner control arm bushing wear, on top of the tie rod and rack wear. Your symptom points to rack wear, since the only thing you are changing with the centering bolt is the radial position of the rack within the tube. For grins, after you remove the centering bolt, brace the steering wheel, then see if you can gently push/pull at 3 and 9 o'clock positions on front wheels to bring the toe reading back to what it was with the bolt in place.
FWIW, I use the centering bolt to make sure the rack is centered, then use an old school steering wheel brace to keep it straight. Then the bolt comes out before any other adjusting is done. The rack then sits pretty much where it "normally" does in the tube. This shows up with noticeably better repeatability in toe settings.
----
The 928 is particularly sensitive to correct front alignment, and demands maybe 100 miles of driving to get the suspension settled. Alignment sessions start with ride height and corner balancing. 3/4 Tank of fuel, and a couple bags of sand or similar in the driver's seat to mimic my fat butt. Make any ride height and balancing adjustments, drive the car, measure again. Then start on the actual alignment settings. Toe, camber, caster, in that order. Cycle through camber and caster until both are perfect as they share adjustment cams, then toe again. All must be done without raising the car on the suspension, one of the things that helps with the "centering bolt out" decision. The front trays have to be out for reasonable access to the bolt. I don't have an alignment rack, so any adjusting is done laying on the floor reaching in from behind each front wheel.
I started doing my own alignments after a well-regarded shop in Los Angeles managed to screw it up. The car ate a set of new Pilot Sport tires in a few hundred miles. Took it back for another check. Both times I sat under the car with the tech, and both times the machine said it was correct. Turned out that one of their wheel fixtures had been dropped. By the time I/we found out and I was back for a third visit, I was well on my way to gathering the tools and time to just do it myself. About six months after, a local 928 owner in my garage for a clinic day, had just been aligned a week before, so we (five or six cars/owners that day) had a chance to compare his serious pro alignment with my DIY. Results identical. I've been refining and simplifying some parts of the system, and so far only one detail in the toe measurement method has been changed to simplify the process.
Should folks do their own? Um, sure, if you have a few hours and have purchased or fabricated the tools. Otherwise, go with the recommendations of friends or your local PCA chapter for best local alignment place. The machines have gotten a lot better in the last 25+ years since I started DIY'ing mine. For the 928 anyway, the biggest surprise for the shops is the requirement to not raise the car up before measuring. That means that I get to do all the wear checking, I get to do the ride-height and corner balancing, tire pressure adjustments, etc., all before I show up to wherever the caster-camber-toe measurements and adjustments will be done.
Tomorrow I am taking it in to the alignment shop.. but I have to say that with my toe clearly out--the steering wheel is at aprox 45 degrees from before--the car has never tracked so solid & straight; the road crown doesn't even knock it off its path. Much better than the factory setting LOL!
Your experience makes me think of the "quick and dirty" alignment I did just to get my car back on the road last winter. The car was tracking and steering so much better than it ever had after bringing it to shops in the past! It made me wonder what those "pros" were really doing...
dr bob wrote: Tue Apr 28, 2026 10:53 am
The centering bolt pushes the rack to the rear of the car, inside the tube
Actually, my manual rack has the bolt on the bottom so I suppose it pushes 'upwards'.. but regardless, I understand a lot more now
dr bob wrote: Tue Apr 28, 2026 10:53 am
FWIW, I use the centering bolt to make sure the rack is centered, then use an old school steering wheel brace to keep it straight. Then the bolt comes out before any other adjusting is done. The rack then sits pretty much where it "normally" does in the tube. This shows up with noticeably better repeatability in toe settings
Thank you Dr Bob for your timely post. Just got back from the alignment shop. They let me install the bolt and this time, I tightened it by hand with a teeny bit more with the wrench, ensuring the wheels wouldn't move on the turntable.
I watched the tech set the toe then I removed the bolt. On the screen, the toe didn't budge.
Though I knew enough not to bottom it out, clearly I was over-tightening that bolt in the past. Lesson learned.
The tech agreed that all appears tight and proper... charged me very reasonably for the 30mins time of setting the car up and the minor adjustment... and off I went with the car driving great
Except I swear my severe off-toe (-1.5 on right side, -0.5 on left) definitely tracks a more solid straight ahead than the proper setting go figure lol
The rest of my alignment is all within spec ("green" on the hunter machine). A very boring stock setup but for a daily driver, works just fine. My summer tires are simply all seasons after all
dr bob wrote: Tue Apr 28, 2026 10:53 am
Should folks do their own?
This lesson has me re-thinking my position and I can totally see how someone can do a good job--and have a fun time at it--with a proper setup.
Unfortunately, that means a lot of things many don't have.. such as a clean, flat floor.. all the cool custom tools.. and quite a bit of time to tinker with it all.
Oringojin wrote: Tue Apr 28, 2026 11:27 am
Your experience makes me think of the "quick and dirty" alignment I did just to get my car back on the road last winter. The car was tracking and steering so much better than it ever had after bringing it to shops in the past! It made me wonder what those "pros" were really doing...
I suspect that the factory alignment specifications are a trade-off of sorts and that in some cases (such as I experienced with off-spec toe) you can actually get the car to feel more locked in with off-spec settings
But probably wear your tires faster and who knows what other issues
Over the years I have also noticed big differences with tires. Had a set of Daytons on a MKIII Golf once and wow those felt so tight. Never had another pair of tires feel like that. They were very soft though and wore out quick
Getting into the tedious weeds here a bit. Read at your own peril...
Know that there are a few differences to consider when you do a technically perfect alignment vs. a 'perfect for road driving here' alignment. To avoid comebacks for 'pulling', many shops will purposefully add some compensation for road crown; absent that, the car will tend to fall off the edge of the road if you let go of the wheel. They may also be offset if the rear toe is offset, as you might find in a live-axle car or one that's had frame damage. Or just wear. Alignment techs call this 'thrust angle', something that needs correction at the front to avoid 'pulling' under drive load, then opposite pulling under braking. Otherwise, toe settings specifically compensate for predicted wear and deflection in the suspension, with a driving down the road target of 0º particularly under braking.
Folks who track their cars will add camber to keep the tire contact even while at speed in corners. They will also push toe settings out some to improve initial turn-in 'feel'. In a road car, this combination will pretty quickly wipe the inner tread ribs. The camber alone isn't as tough as the toe-out; a car that offers that combo of sharp immediate turn-in stability will scrub the inner couple inches to cords in a few thousand miles.
More:
The steering rack and tie rods are intended to be at the same height as the outer tie rod centers at running ride height. Stray far from that height, and see more dramatic toe changes with suspension travel. Cars that have sagged or been purposefully lowered see the more extreme effects, especially if the inside suspension extends past that tie-rods-level height while the outside compresses even more. Think "bump steer", but exacerbated by the opposite travel on the non-bumped side. A bit of anti-dive designed in to the lower control arm pickup points reduces the toe change under braking, but that benefit diminishes quickly if you add steering lock under that same braking. Brake -before- the corner, then let the suspension do its job keeping both front wheels pointed where they need to go as you steer around the corner.
In our little volcanic neighborhood in central Oregon, roadbeds tend to include a lot of cinders. Over time, load, and traffic, asphalt sags as the cinders underneath are slowly crushed. Not a serious problem if your car's 'track' width matches the trucks that have caused the crushing. Else, my 928 will sort-of follow the grooves, but will 'pull' slightly depending on which tire is sitting slightly out. There's no setting or adjustment that will compensate for this effect, unfortunately. I have caster set to minimum, which incidentally is close to factory spec, but it still follows the guidance of the wheel that isn't riding in the middle of the wear groove. The state DOT here does "partial" paving every couple years to fill them in, an interesting short-term fix. We are still pushing the cinders closer to the magma pockets from which they were originally spewed...
dr bob wrote: Wed Apr 29, 2026 11:15 am
In our little volcanic neighborhood in central Oregon, roadbeds tend to include a lot of cinders.
Up here in Ontario, our roads are so full of potholes they appear as swiss cheese. This year is the worst I've seen. Despite all my attempts at dodging, I land in quite a few daily.
The rim repair shop nearby is perhaps the busiest business around and I am hardly kidding. I have been their customer twice.
Perhaps yet one more reason for me to take my near-forty year old car with me overseas next year: a simple pleasure of driving it on fair roads & freeways
Sometimes I notice differences in alignment specs for non-North American versions of cars and I think ours have those as well (have to check). Wonder if this is due to differences in road construction or something else
