I did a writeup on Yotatech a while back when I aligned my IFS 4Runner. While caster and camber are fixed on a solid axle truck, the method of measuring the toe-in based on geometry is applicable and works well- I've put 20K on my truck since my driveway alignment and it drives beautifully and there's never little tire wear (it must be acknowledged that an alignment rack in a shop is going to be more slightly accurate, but in a pinch, this will do:
Steps 11 onwards are applicable to Cruiser and other solid axle trucks. I included the other part should anyone with an IFS truck read this thread.
DRIVEWAY ALIGNMENT PROCEDURE
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
- thin (1/16") fluorescent string (pink was very visible)
- ruler that measures to 1/32" or 1mm
- floor jack and stands
- 12, 22, 24mm sockets
- breaker bar
- torque wrench that does 150ft-lbs
- 2 cans strong penetrating oil (PB Blaster, Lloyds "Move it" etc)
- pipe wrench or visegrip pliars
- a handful of wooden shims (or any scrap material that you can make shims from)
- anti-seize
- hammer and chisel
Caster, Camber and Toe
Caster
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
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
Cam bolts are used to adjust caster and camber. Instead of explaining them, here's a few videos I took during the alignment.
Toe
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.
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.
- Park the truck on a flat, level surface with the steering pointing dead ahead. Concrete levels itself (asphalt doesn't seem to). I had to borrow a neighbour's concrete-floored garage.
- Set ride height so that the driver's side is the same as the passenger side. To do this precisely, measure vertically from the outside of the rim to a spot on set location on the fender (ie: 20.5" out from the door-fender panel gap. After the alignment, I bumped up the ride height 1/4" on the drivers side to counter act the effect of a 200lbs driver (I usually drive alone). This of course is not nessecary, but I was feeling a little obsessive-compulsive.
Measure a distance away from the panel gap and mark the fender with tape, crayon etc. This ensures you're measuring from the same on both sides.
- Break loose the cam nuts and the tie rod adjuster sleeves. My cam nuts cam easy after hitting them with penetrating oil, a couple swift kick with the sole of my boot to the breaker bar was sufficient to loosen the bolts enough to turn the breaker bar by hand. In contrast, my adjuster sleeves were a royal PITA. I need torch to heat them up, lots of penetrating oil, and a hammer & chisel to open up the split in the sleeve. I don't mean driving the chisel (or screwdriver at a 90* to the split, but instead at a 45* angle as to push the one half away from the thread on the tie rod, then do the same on the other side of the split. You should have flared/ spread the ends of the sleeve. Spray some penetrating oil into the newly-opened gap between the tie rod threads and the sleeve and wait a couple minutes. Finally, I used vise-grips to work the sleeve loose. Work it back and forth until eventually it breaks free.
Replacing the tie rod ends
I replaced my TREs about a week after the first alignment attempt, both had 1/16-1/8" of play- way too much. The studs were really stuck- and the pickle fork wasn't going to cut it. I ended up trying TRE/ ball joint pullers, but they wouldn't fit over the steering knuckle. A pitman arm puller proved to be the solution. It was simply a matter of tightening up the puller on the tie rods, then give the joint a hit with the pickle fork- should pop right out.
Pitman arm puller in action on another vehicle:
- Take two pieces of sheet metal, put oil in between and place under the front tires. These will allow the camber and caster to be set with the weight of the tires on the ground as the tires top plate (contacting the tire) can slide relative to the ground on the bottom plate.
- Drape a plumb line from the top of the tire down.
I placed a little container of fluid (oil, water...whatever) in which the weight was immersed to prevent the weight from acting like a pendulum.
- Measure off the top and the bottom of the rim to the string. The measurements should match at the top and bottom in order to have "0" camber. Each millimetre difference represents X degrees when measured off the top and bottom of the rim.
- Set the rear cam bolt out a couple index marks out from the front cam bolt, then move both bolts together until the camber is correct. The caster should be a little a little tiny bit more on the drivers side, try one index mark more on the drivers side compared to the passenger side. You're going to have to experiment with this one until the steering feels right to you.
- If it pulls to the oncoming lane, decrease the caster on the driver side, if it pulls to the passengers side, increase the drivers side caster.
- Tighten all 4 cam bolt nuts to 145ft-lbs.
Driver's side rear cam bolt
Passenger's side rear cam bolt
Driver's side front cam bolt
Passenger's side front cam bolt
- Take the truck down off the jack stands and roll the truck back and forth to releive the tires (the sidewalls will roll as the front track width changes as weight comes onto the suspension).
- A trick I thougth of for setting the toe without rolling the truck back and forth after each little adjustment was to put the jack under the LCA as close to the wheel as possible and lift the tire until it is just barely thouching the ground. This way the tire will be able to turn without turning the steering wheel. LIfting the tire slightly works better than the oiled plate method described earlier as the steering wheel will not turn with the tire being adjusted off the ground.
- Run string from the tread on the front to the tread on the rear tire
- The front track is wider than the rear, so place a roughly inch-thick block of wood between the tire. Then turn the adjuster sleeve until trailing sidewall of the front tire just touches the string without causing it to deflect.
It helps to look down the string from the front with a bright light shining at the trailing edge where the string crosses. Fluoresent string also comes in handy.
- Now measure the distance from the string- to-rim lip distance at the front and back of the rear tire. Adjust the toe until the difference between front and rear measurements is within 1/8" of 1/16" toe-in (rear measurement is 1/8" larger than the front measurement), in metric this is about 1mm+ 2mm. I set my toe at 1/16" as my tie rod ends are loose and the play will use up all the allowances in the specs. I feel this way of measuring toe is accurate to 1/16", maybe even 1/32", so it is definitely accurate enough.
Above, the string runs 1 3/16" away from the trailing edge of the rear tire rim, below, it runs 1 2/16" away from the leading edge of the rear rim. The 1/16" difference between the measurements indicates that I have 1/16" toe in on the front tire.
It may seem counter-intuitive that you are measuring toe off the rear tire, but that's how its done. The rear tire acts as a reference centre-line as it is perfectly aligned with 0 toe (by nature all non-steering straight axles are 0 camber, 0 toe). The front tire dictates the angle. Measuring off the rear tire gives toe measurement. Think back to high-school geometry.
Note that the toe-in measurements should be the same, the passenger side rim-string measurement on passenger side will likely be different DS rim-string measurement. This is because you rear axle isn't likely perfectly centered, especially on coil-sprung 4Runners. Unless adjusted, the panhard bar (coil springs only) will push the axle to the DS (if suspension is sagged) or the the PS if the suspension is lifted.
Each time you change the tow, you must re-shim the string so that the front tire touches the string but does not cause it to deflect.
Here, I am using a putty knife as a shim. You can also see the wood chips I used to fine tune it so that the pink string touches, but does not deflect off the trailing edge of the front tire. The shim serves to hold the string in place while you take the measurements. I found it impossible to keep the string steady between positioning the string relative to the front tire and taking the measurements.
- Check that the steering wheel has not turned itself (it shouldn't if the tires are not touching the ground)
- Repeat for the other side
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:
- When adjusting toe, take tire-ground friction out of the picture by placing two tiles (shiny side to shiny side) under the tire or jack the tire up off the ground by placing a floor jack under the LCA as close to the wheel as possible.
- Adjust the torsion bars with no weight on the tires, otherwise you'll bust the adjuster bolt
- If your truck hasn't been aligned and had the t-bars adjusted in a while, buy at least one new adjuster sleeve, one nut and bolt for the T-bars (dealer item)
- when adjusting the cam bolts, use the markings on the 24mm side as the other side is merely an indexed washer and has some play relative to the shaft.
- adjust the adjuster sleeves until nearly all the thread on the inner and outer tie-rod ends is exposed and liberally coat the threads in anti-seize so that they are easy to adjust next time.
- Crowned 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. EDIT: I did a bit more research and it seems compensating for road crown in mostly a throwback to the days of mostly two-lane roads and bias ply tires. I may play around with giving the drivers side a little more caster, but we'll see.
Other resources:
SDORI alignment after BJ spacers
Toyota 86-95 4WD Alignment Instructions
Really good string alignment page, oddly for Hummers (who aligns their own Hummer?!)
String Alignment Method for Toe-In
From some Subaru site, not as useful as the two previous, but worth a look:
HowTo: 4 wheel alignment (toe and thrust angle) - NASIOC
