I had previously done it with the string box method, which was OK, but I doubted its accuracy and it was a real pain in the backside to setup and get right. It so happens that I had to do the alignment again anyhow due to the new front track rod end being marked L and R incorrectly (pattern parts), so I swapped them around and devised a cunning plan……….
Flicking through the service manual shows how Honda do it (or used to anyway), the system looks pretty simple and I thought I’d have a go at replicating it.
Another issue I had was the 4WS light coming on after about 5 mins of driving; I was expecting this as I’ve had pretty much everything in pieces. The code was 20, which is front sub or main steering angle sensor. Most likely I thought it would be misalignment of the main sensor behind the steering wheel; that is, it is not set to electronic neutral when the road wheels are straight.
Setting up the car from the inside.
So, first things first is to get the steering wheel into neutral mechanically and electronically, this means finding the centre of the steering rack and then adjusting the wheel and main angle sensor to suit.
The easiest way to find the middle of the rack is to turn the steering wheel to full left lock, and then put a piece of tape on the bottom of the wheel in this position, then turn the wheel to full right lock, and put another piece of tape on it. Then turn the wheel to centre(ish) the point between the two pieces of tape should be at the top of the wheel when straight. If not you’ll have to take the wheel off and put it back on straight.
Even though I had measured the rack (to what I thought was centre) when I refitted it, the wheel was still about 15 degrees out.
So, with the wheel off, I could also see the main steering angle sensor, knowing I had the middle of the rack, this should also be in the centre too, noted by a yellow paint mark that should be at the bottom. If not, you need to move the sensor until it points down (see pages 17-85/86 of the manual), once done, refit the steering wheel straight and bolt everything back together. Mine was 45 degs out, which probably explains the warning light.
So now we have a steering wheel that is aligned to the centre of the rack and the angle sensor, which can tell the electronic 4WS ECU that this is so.
Manufacturing a measuring system.
I cut 4 lengths of timber, exactly as long as my wheels, so they can sit flush but not touch the tyres. This would be even better with ally or steel, but I used what I had to hand.
Then I created a set of measuring marks with excel, setting a line 2cm for the front wheels and 2.5cm for the rear wheels. The rear track on a 4th gen is 10mm wider than the front, that’s 5mm different per wheel. I also printed 2 lines either side spaced at 1mm apart, to help with the rear wheel alignment.
I then proceeded to stick the printed markings onto the timber, as precisely as I could possibly do so.
Once this was done I screwed 4 eyelets onto each end and marked which wheel each timber piece belonged to.
And that’s about it.
Aligning the road wheels.
The front wheels should be set to straight ahead (i.e. no toe in or out) and the rear wheels set with a little toe in.
Move the car onto something that will allow the wheels to turn freely and without much resistance, the best thing to use here is some vinyl tiles and grease making a sandwich (vinyl as the bread and grease as the filling).
Lock the rear steering rack with a locking pin; I parked the car with the 4WS light on, which hopefully should ensure that it is centre when being locked.
So take the timber blocks and attach them to each wheel, considering that the fronts are different than the rears. I used tape which seemed secure enough, though you may find something better.
Once the blocks are on, attach a piece of string (making sure it is taught) to the front and rear eyelets on the o/s and then on the n/s.
By looking down your high tech gauges, you can see where the wheels sit.
If they are out, as in the picture, get crawling on the floor, undo the locknuts on the control arms and then adjust away until the string line sits on the centre line nicely, this is why I liked this system as you can look down the gauge as you are moving the wheel.
Go round each corner and set to perfectly straight ahead. One thing to note is to ensure that you move the outer rod balljoints to the centre of their travel once you have turned the inner rods.
Now with that done, lock the front locknuts in place.
Now go round to the rears and adjust each wheel to toe in a little, with the marks we made set to 1mm increments, where to adjust is relatively easy as it should be 2mm toe in at this point.
You can double check that both wheels are the same by looking from another angle, using the bodywork of the car to ensure that your eye is in the same relative position.
Now that is all done you can lock the rears into place and remove the locking pin.
If you disconnected the battery, turn the steering to full left lock and full right lock when you start it.
Now stand back and revel in your own awesomeness (as I did now the car goes straight and no longer throws a code).
In total this process took me 3 hours start to finish, though just the road wheels part was only 30 mins.
So, in summary:
Find the centre of the steering rack.
Align the steering wheel to suit.
Align the main steering angle sensor to suit.
Align the road wheels to suit.
idea...
I think after we've watched you do it (how many 4th gens are going? 5 is it? 
) times, then we might just have picked it up and be able to have a go ourselves, next time... 
