|
driveway alignment write-up
DRIVEWAY ALIGNMENT PROCEDURE
http://photos-b.ak.fbcdn.net/photos-...11705_5533.jpg After installing BJ spacers and relaxing the T bars, I was in dire need of and alignment. Here's what I did. Disclaimer: While it drives well, and the measurements I took suggest the alignment is pretty good, chances are it won't be quite as good as a mechanic at a decent shop could do. One thing for certain, this alignment is going to get you to a shop without any noticeable tire wear. Tools
Caster, Camber and Toe Caster http://www.thepetricasa.com/home/IH_...ign_Caster.gif Caster helps the steering centre itself. Imagine a shopping cart, the wheels center themselves as the point at which the wheel contacts the ground is rearward of the the steering axis (imaginary line drawn between the upper and lower ball joints and continued into the ground). Too little caster and steering feels nervous; too much, and low-speed steering feels heavy. As my truck has power steering, and I spend lots of time on highways, I put as much caster in as possible. Spec says it should be 2* + 45', but there is no way to easily measure this with shade-tree mechanic tools. On Hi-Trac IFS (1986-1995), caster is adjusted by pushing the rearmost side of the lower control arm (LCA) out and bringing the frontmost side inwards (relative the rear) towards the truck centre line. It is important to ensure that the caster is the same on the driver's and passenger's side. Camber http://www.driftclub.gr/v3/images/st...mber_angle.jpg Tire side walls flex when cornering, in order to keep the tread parallel to the ground when cornering hard, the tops of the tires are tilted inwards on most cars. Too little camber and the tires don't stay in proper contact with the road; too much and the insides of the tires wear. To change the caster while maintaining camber, turn the cam bolts in opposite directions. Some have suggested that the caster should be a little negative on the front tires off top-heavy, rear solid axle vehicles as to induce understeer. Understeer would be safer than over as it keeps prevents sliding sideways which may lead to a roll-over. On our trucks, zero camber (tire vertical to road) is "in spec" (0*45' + 45')and is easy to aim for using a plumb line or a carpenter's square. Like caster, it is important to ensure that the camber is the same on the driver's and passenger's side. Camber is set by pushing LCU out further than the UCA (upper control arm). To change the camber settings without disturbing the caster angle, turn the cam bolts in the same direction. Caster adjustment [youtube]http://www.youtube.com/watch?v=GEjSYpMjrBg[/youtube] Cam bolts are used to adjust caster and camber. Instead of explaining them, here's a few videos I took during the alignment. [youtube]http://www.youtube.com/watch?v=zmgTCKbOXI8[/youtube] Toe http://driftjapan.com/blog/wp-conten...vs-toe-out.jpg The idea behind "toe-in" is to preload the steering a bit by making the wheels track towards the centre and add to straight-line stability at the cost of quick steering response. Too much toe in or out will wear the tires in a saw-tooth pattern. Toe is set by shortening or lengthening the length of the tie rods by turning the tie rod adjuster sleeves. Spec calls for 1mm + 2mm. I set mine at 1/16" as my rod ends are worn out, and I don't want the steering being able to go too far out of spec with the worn rod parts. Worn out rod ends will make getting a precise measurement impossible. http://photos-b.ak.fbcdn.net/photos-...11721_1732.jpg Basic Alignment Procedure after installing BJ spacers i) max out the rear cam bolt ii) turn the front cam bolt until the wheel is vertical (0 caster) as checked with a plumb line iii) replicate the settings on the opposite side of the suspension that you just worked on, iv) set toe with a string so that the the tires are pointed dead ahead with the string method described later. Toe must be the same on both sides or the steering wheel will be crooked. v test drive, change caster and camber according to feel. Now, in detail it should be noted that the suspension must bear the weight of the truck during the alignment procedure or else the alignment will be "out". The caster, camber and toe all change depending on how much weigh is on the suspension- as you'll obviously be driving it with the full weight of the truck on your suspension, the alignment is set up for that particular suspension height. The driver doesn't weigh enough to bother taking into account. Keeping the weight on the tires makes it impossible to measure the changes to the alignment settings unless you employ one of several tricks. The easiest is to place a jack under the lower ball joint and raise the tire a hair above the ground- just enough so that you could slide a paper under the tire is fine. Make sure your tires are pumped harder than usual so that the weight of the truck doesn't compress the tires (rim to ground distance). This allows only the tire being lifted to have the toe adjusted.
Test drive problem solving If the steering feels too heavy, there it too much caster angle, bring the rear cam bolt in a couple notches and reset camber, then toe. if the steering pulls to one side, lets say the right, check your cam bolts are adjusted the same from side to side. If your steering wheel is not straight, then bring one tie rod in and the other out. Driving impressions The weather has been terrible here, so test driving the truck and paying attention to the steering was though as there was tonnes of slush patches on the highway. That said, the truck seems to track straight (steering wheel is dead-on, none of the cars we've ever owned have had the steering wheel set set straight after an alignment). Steering is quite heavy, I thought I'd like it like that, but now I'm not so certain, its not a problem, its just not to my taste. I think I may reduce caster a bit when I replace my tie-rod ends in a couple months. The truck seems to act a little more top heavy, this could be that the camber isn't quite on or this may be due to the ball joint spacers allowing the front suspension to flex a little easier. I'm pretty sure the toe is set as well as two worn-out outer rod ends will allow. Overall, I am very happy with the results and I doubt I will be bringing my truck to an alignment shop any time soon. Pointers that are worth mentioning twice:
Other resources: SDORI alignment after BJ spacers http://www.sdori.com/SDORI_4WD_Align...ions_Main.html Really good string alignment page, oddly for Hummers (who aligns their own Hummer?!) http://www.hummerknowledgebase.com/susp/string.html From some Subaru site, not as useful as the two previous, but worth a look: http://forums.nasioc.com/forums/show....php?t=1093484 |
subscribed...
I've been looking for a write up on this, specifically which bolts to turn to effect which of the 3 aspects of the alignment. So far so good, keep it coming! -thanks |
Adjusting Caster also changes camber. Changing Camber also adjusts caster. It's a finicky thing to mess with in your driveway.
Balljoint spacers also throw a headache into the mix. It complicated Caster/Camber 10x fold IMO, even my alignment shop had a headache. As where your torsion bars are set directly effects camber, which when you adjust it, effects Caster. In theory you think, I'll just adjust both cam nuts EQUALLY. Well much easier said than done. All 4 of my cam bolts are different, literally. Some turn easier than others while my right rear one the tabs that hold it in are from the factory, to close to together so the damn cam bolt wont even deflect all the way one way or the other, maybe a 3rd of what it should. Not to mention, getting leverage on the inside and outside (nut and bolt head) can be tricky. The cam bolt likes to turn with you turning the bolt. ... and not in the way you want it to. I reccomend taking pictures of all 4 cam bolts before starting this. Then referring back to them to keep them as equal as possible when you adjust each.. dont rely on memory! Also, with BJ spacers because camber is no longer equal as the wheel travels up and down, when you adjust these bolts (easiest when the truck is jacked up) .. you'll find this to be even more difficult. because, ok, you make your adjustments, you lower the truck.. well until you work that suspension, you won't know where exactly your camber is going to sit finally. So.. its a ..adjust... drive, adjust drive... adjust.. drive. ... you're gonna end up doing this anyway. You think ok i got this thing perfect, go to test drive it.. come back and go.. WTF my camber is all whack, what happened? I've been doing home alignments for a long time now. I had a shop do it once but as long as the truck drives fine (ie no left/right pull) camber is up n down and tires wear fine I'm golden. |
nice job, very helpful
|
...THIS is why I have been dragging my feet on installing the BJ spacers that I've had sitting in the garage since August. It just seems confusing and gives me a headache just looking at it. Nothing against SDORI's homebrew alignment writeup, but Matt's is a little better as it includes pictures of which bolts are which.
This is definitely at the top of my list of chores 2009. |
Originally Posted by highonpottery
(Post 51019739)
...THIS is why I have been dragging my feet on installing the BJ spacers that I've had sitting in the garage since August. It just seems confusing and gives me a headache just looking at it. Nothing against SDORI's homebrew alignment writeup, but Matt's is a little better as it includes pictures of which bolts are which.
This is definitely at the top of my list of chores 2009. If Matt had gotten this done sooner I'd have done it myself, he is so lazy sometimes.... :jk: |
|
Originally Posted by drguitarum2005
(Post 51019884)
why do you have a spacer (looks like some sort of chisel or tool for spackle) between the string and rear tire? unless your track widths are different that would unevenly affect your toe, unless you used that spacer to get the amount of "toe-in" that you wanted
|
Alright. The write-up is pretty much done. I may add photos or explanations if there are points the people don't understand.
|
Updated again. I drove it to class today and I think I actually like the steering heavy in actual driving conditions. I do worry a little bit about wearing out the weaker steering components faster due to lots of caster and BJ spacers (i.e.: idler arm bushings, rod ends). If the steering feels heavy at the wheel, I cannot imagine the forces to the actual components "downstream" of the power steering pump. That said, the tire seems to track better when one tire goes through a major puddle- that I like.
I am comfortable setting the caster by trial and error, I am confident in the technique for toe (it measures more precisely than I thought it would- 1/16 easily, maybe even 1/32"), but the camber adjustments I am not so happy with. I know its decent, but unless you were to rid the tire of the bulge where the tire contacts the ground by pumping it up beyond 75 psi, I don't see a way of accurately measuring the caster. I don't like the idea of using a square against the ground as even concrete doesn't level that well. >>Can anyone think of a way to accurately measure camber angle with the tires on the ground?? I've thought of spraying a line of paint, then scribing a fine line through the paint and measuring camber off that. http://www.extremehowto.com/xh/hotpr...es/wheels5.jpg Here in BC, we get a tonne of rain, so roads are crowned heavily (centre of road is domed to drain water off the road). Right now, on crowned roads, the truck pulls a little towards the ditch. It tracks dead straight on flat roads. Add caster angle to the uphill (driver's side) to counteract the effect of road crown. This way, the driver's side wheel centers itself dead straight, and the passengers side toes in to counteract the effect of gravity on a crowned road. Basically all that means is that instead of pulling towards the ditch, you tract straight on a crown or away from the ditch on a flat (no crown) road. |
Could someone take pictures of their shop-aligned IFS cam bolts? Ideally i get some pics of professionally aligned stock and with BJ spacers. I'd like to see where they sit. I meant to do this before I started, but forgot.
|
Too much camber like this can result in the inside of the tire wearing faster than the outside.
http://failblog.files.wordpress.com/...-tire-fail.jpg |
Hey Matt, I can take some pictures of my cam adjuster bolts but my alignment is not %100. The guys at kal-tire (after going there 3 times) told me they could not get it any closer...
I think these guys are retarded. Im gonna attempt to re-align this summer with your write up |
Mostly, I want to see roughly the difference between frt. and rr. cam bolts on a level-ish truck to get an idea what "in spec" roughly looks like, i.e.: I know for instance that it would be unlikely to be in spec if one cam was all the way in, and the other, all the way out.
Below, the setting is "out" as well, the caster is much too + to be in spec and the steering is quite heavy. I wanted heavy steering, but maybe not this much. Next alignement, when I get my new rod ends, I will take the rear in a bit (turn cam bolt clockwise) and push the front out (turn cam bolt counter-clockwise) to reduce caster and bring maintain camber. Rear http://photos-a.ak.fbcdn.net/photos-...11712_8213.jpg Front http://photos-c.ak.fbcdn.net/photos-...11714_8956.jpg |
good trick however u will never get it as accurate with this setup as with an alignment machine ive realigned quite a few cars that the owner did him self and u would b suprised how much a difference there is i mean u can get it close but your not going to b dead on
|
Originally Posted by Matt16
(Post 51020876)
>>Can anyone think of a way to accurately measure camber angle with the tires on the ground?? I've thought of spraying a line of paint, then scribing a fine line through the paint and measuring camber off that. Camber... Whats wrong with how you were doing it? You can hang a plumb bob from a string (get it as close to the wheel/tire as possible) and then just measure from the string to the top of the lip of the wheel, and then from the string to the bottom lip of the wheel. then you can use some trigonometry to figure out what the angle is. Assuming that there is some negative camber (top measurement will be larger... farther from the string). top measurement: 1.24" bottom measurement: 1.20" So basically you will picture a triangle, and figure out the angle. The triangle starting from the bottom lip, going straight up, and then straight in to the upper lip. So the one side will be the diameter of the wheel from lip to lip, the next side will be the difference in measurements (1.24-1.20=0.04). Then you can use Tangent with the values you have to figure the angle (angle of camber). Hopefully that makes sense. I dont have time right now to make a diagram, but I have one somewhere online. |
Originally Posted by darksoldier313
(Post 51026322)
good trick however u will never get it as accurate with this setup as with an alignment machine ive realigned quite a few cars that the owner did him self and u would b suprised how much a difference there is i mean u can get it close but your not going to b dead on
Perhaps you could explain how caster, camber and toe are measured on the machine. That would be really valuable. If the camber is too dar out, is the machine just going to go on the fritz and show "error"? I saw a parked Ford with a Twin Traction Beam front axle the other day that had a good -20* camber on each wheel. I asked the owner what was with, and he said that two alignment tech couldn't figure it out and that the camber changed between going backwards and forwards. Granted Ford TTB was one of the weirdest suspension designs seen in modern-era trucks, I think an alignment shop should be able to figure it out. That, and the fact that the steering wheel always comes back crooked, makes me think that you should get it as close as possible to spec before bringing it to the alignment machine operator.
Originally Posted by aero
(Post 51026514)
Camber...
Whats wrong with how you were doing it? You can hang a plumb bob from a string (get it as close to the wheel/tire as possible) and then just measure from the string to the top of the lip of the wheel, and then from the string to the bottom lip of the wheel. then you can use some trigonometry to figure out what the angle is. Assuming that there is some negative camber (top measurement will be larger... farther from the string). top measurement: 1.24" bottom measurement: 1.20" So basically you will picture a triangle, and figure out the angle. The triangle starting from the bottom lip, going straight up, and then straight in to the upper lip. So the one side will be the diameter of the wheel from lip to lip, the next side will be the difference in measurements (1.24-1.20=0.04). Then you can use Tangent with the values you have to figure the angle (angle of camber). Hopefully that makes sense. I dont have time right now to make a diagram, but I have one somewhere online. |
no offense to the people at the shop u take your cars to but i never let a car leave with a crooked steering wheel thats why we test drive. and u camber being off isnt going to bug it out as much its usually toe which can be a result of camber however sometimes i have had to adjust close to before i could align and -20 degrees is horrible sounds like something is broke or bent if im not mistaken i think the twin i beams use a cam slug and i suppose if u install the wrong one it would do that but theres a fancy little tool on most newer align machines called acc (automatic cam calculator) tells u what size and position to put it in and pretty much the machine does exactly what your doing with the strings its all calculations basically it calculates the middle between the sensors creates a center point of reference and calculates based of the anlges of the sensors but it does it in degrees instead of inches and millemeters tho u can convert it does down to like .00 degrees not to mention it shows all 4 wheel alignments instead of just the front tell em to come by my work ill fix em up
|
Originally Posted by darksoldier313
(Post 51026684)
no offense to the people at the shop u take your cars to but i never let a car leave with a crooked steering wheel thats why we test drive. and u camber being off isnt going to bug it out as much its usually toe which can be a result of camber however sometimes i have had to adjust close to before i could align and -20 degrees is horrible sounds like something is broke or bent if im not mistaken i think the twin i beams use a cam slug and i suppose if u install the wrong one it would do that but theres a fancy little tool on most newer align machines called acc (automatic cam calculator) tells u what size and position to put it in and pretty much the machine does exactly what your doing with the strings its all calculations basically it calculates the middle between the sensors creates a center point of reference and calculates based of the anlges of the sensors but it does it in degrees instead of inches and millemeters tho u can convert it does down to like .00 degrees not to mention it shows all 4 wheel alignments instead of just the front tell em to come by my work ill fix em up
|
Alright, I figured out how to set camber to my satisfaction. Once again, I used a plumb line, but this time, I measured off the rim with the tire on the ground. I parked in a leveled concrete garage, the set up the plumb line using some wood chips to shim the plumb line so that it did not deflect off the lower sidewall bulge. This time, in order to stop the plumb line for acting like a pendulum, I immersed the weight in a container of water (syrupy gear oil would have worked even better).
As camber changes as the suspension cycles, if you set the camber with the weight off the tires, the bottom of the rim will be cambered in a little over 1/4"- far too much positive camber. The problem with setting camber on the ground I had before was that I didn't have room to roll the truck back and forth after each adjustment, so inevitably, the it was too difficult to dial in the camber. I thought about different low-friction surfaces I could use so the tire could slip from side to side, but couldn't convince the local hockey rink to let me borrow the ice for a bit. I settled on two 16 gauge (I think, its about 1/16" thick) 12"x12" squares of sheet metal laid on top of each other with grease in between. Placed under the tire, the tire can slip from side to side riding on the top plate. Cheap, simple and it works. I can easily adjust the cam bolts as the tire slip in and outwards. I was able to get the passenger side rim cambered in 1/32" (translates into -0.12* caster on a 381mm [15"] rim). Spec is 0*45'+ 45* if I recall, so this puts me well within spec. On the drivers side, I maxed out the camber at +1/32", which puts me at +0.12*. While this isn't perfect, I'm going to try it. I really doubt I'll notice, and it isn't going to eat tires like that either. I also dialed back the caster, as I felt the steering was too heavy. It was nice on the highway, but around town, it felt a bit like a cement truck. I have no way to measure caster, so as long as it tracks nicely, doesn't pull or eat steering parts, I'll be happy. Replacing the tie rod outers tmr with 555 brand tie rod ends sold by Beck Arnley. They're grease-able which is nice. Update: Re-adjusted D-side camber so that the wheel is now cambered in 1/32"- so both tires are now cambered in at -0.12* (as calculated to my measurement which I feel are accurate to better than 1/32" or 0.12*). With the help of a pitman arm puller and a pickle fork, I was able to separate the rod end for the knuckle. Back in a bit... |
| All times are GMT -8. The time now is 02:23 AM. |
© 2026 MH Sub I, LLC dba Internet Brands