Below are all the parts that go to make up an Associated front end. If this is put together well and carefully your car will be much better than with a badly built front end.
There are a few tips and tricks to building the front end that help give it a smooth and predictible action, and a default setup that is a good basis to start from.
The standard lower arms can be out slightly from each other left to right in height. Careful flat sanding of the bottom of the arms can be done to correct this, and is recommended anyway to ensure that the bottom of the arms are flat. Alternatively pre-machined arms are produced by IRS that can be used instead that should already match and be flat. These have also been lowered so that smaller front tyres can be used. These are what are commonly called lowered front arms. Below is an example of an IRS lowered front arm next to a standard Associated arm.
It is also advisable to tap the mounting holes in the front arms with an 8/32 inch tap. This will help prevent stress on the arms and chassis tweak when the screws are tightened. Don’t tap it all the way through though. Leave a small amount untapped so the screws lock when screwed in fully.
An L4 (and other cars) comes with 3 different angles of caster block, 0, 5 and 10 degree as shown below. The manual shows the fitting of 10 degree blocks. Don’t fit these, at least at first. Fit the 5 degree blocks instead.
The 5 degree blocks will give less agressive steering than the 10 degree blocks. You might as well throw away the 0 degree blocks. I don’t know of anyone that uses them in the UK.
A good investment is a pivot ball tool. This allows the insertion and removal of pivot balls into the arms without damaging them.
Make sure you fit the pivot balls the right way round ie. with the collar parts pointing inwards towards each other. The pivot balls may be tight in the arms. You don’t want them sloppy, but also not so tight they won’t move either. If they are, carefully squeeze the arm around where the pivot ball fits with a pair of pliers. This will set the shape of the inside of the arm to the pivot ball.
If the pivot ball can move around just by touching it, it is probably too loose. They are not all exactly the same size, so trying another one can sometimes solve this.
As standard the steering blocks are a tight fit on the kingpin. This is how it was designed, but this sometimes binds up the steering by trapping the block against the upper pivot ball. Most people now carefully ream out the arm with a 1/8 inch drill or reamer so that the arm just moves freely on the kingpin. This has to be done very carefully as too much will give a sloppy front end.
Make sure you get the right hole when you ream it, it is easy to do the axle hole instead! Best thing to do is fit the axle first.
It is possible to get threaded stub axles for the front end, in fact those are the ones I use mainly. After putting these in the steering block you will have to ream out the kingpin hole further as the block is compressed when fitting the axle. If you use threaded axles you will have to shave a small amount off the lower suspension arm to stop the inside nut from catching.
Making the front track of the car wider can improve the stability of the car. This can be done by adding the plastic spacer used with an E clip kingpin and then putting the lock nut on backwards to ensure it still locks.
To make the front suspension action even smoother polish the kingpin. I do this by putting the kingpin in a Dremel and polishing with a cloth and a small amount of Brasso. Make sure all the Brasso has been removed before fitting though.
If the upper arm doesn’t move easily on the hinge pin this can also be polished in the same way. This is only necessary at the ends though as the hinge pin does not need to move easily in the caster block.
New kits come with 0.020 front springs. These should be fitted as they are a good starting point. 0.022 front springs can be fitted later if you want the steering to be more agressive. If you have a second hand car, make sure the springs you have are 0.020 by measuring them with a pair of calipers (digital ones can be found on online auction sites for £10-15) and that they are the same length and not collapsed.
Shims then need to be added above the top arm below the E clip until there is no play, but no more than that. Adding shims to put preload on the spring is a good tuning aid but just taking the play out is a good starting point. Make sure both sides of the front end feel exactly the same. This may sometimes need a different number of shims on each side.
In the picture above 5 shims were required between the pivot ball and E clip to take the vertical play out of the kingpin without putting preload on the spring. If you have a new kit you may need to buy some more shims as not many are supplied.
Overall, as shown above the stack on the kingpin from bottom to top should be as follows:
E clip
0.020 spring
Bottom arm with pivot ball (collar up)
Steering block
One shim
Top arm with pivot ball (collar down)
Shims
E clip
If you have a second hand car and it is not built like this either it has not been built correctly or it has been modified.
A fully built front end ready to fit on the car should look like the one above. Note that there is one teflon washer on each side of the caster block. These adjust the static caster of the car, and one each side is the best starting point.
The way to adjust the ride height of the front of the car is to use spacers. The ones I use are shown below, and come in 1.5mm, 1mm and 0.5mm sizes. They can be used together to get sizes greater than 1.5mm.
They are shown fitted on my usual car in the picture below.
Don’t be tempted to try other methods of changing the ride height of the car, like adding shims on the kingpin above the lower arm, as this changes the geometry of the suspension and will adversely affect the handling.
When mounting the front end on car don’t overtighten the screws as this can tweak the chassis. Tighten them just until you feel the screw "grab" the chassis.
