It is usually a good idea to build a spare front end at the same time to save you time at the track in quick change situations.
This Tech Tip originally appeared in the April 2007 issue of Sprint Car & Midget Magazine.
This month, our discussion centers around how to build a front end and how to square it in the car. Remember, it is usually a good idea to build a spare front end at the same time to save you time at the track in quick-change situations.
To get started, you need to make sure you have all the parts and pieces you need to build a complete front end, such as: axle, king pins, spindles and bearings, hubs with bearings, left front combo arm, right front arm, front direct mount rotor and caliper, caliper bracket and tie rod.
Typically, I start by assembling the hubs first. You will need to install six 3/8” bolts into each of the hubs. It works well if you use a vice to steady the hub while you are working on it.
Apply a small amount of Lock-tight to the base of the bolts going into the hub and screw them in all the way (I torque mine to 30 pounds).
With all the bolts securely in the hub, I move to the rotor. Secure the three ½” by ¾” long bolts that hold the rotor to the hub with red Lock-tight, and torque them to 35 lbs. You are now finished with the hub assembly.
Step two, the axle. You will need to ream the king pin bosses at each end of the axle. To do this I use a king pin reamer tool made by Fast Axle. This tool is easy to use and gives you outstanding results. The reason this particular king pin reamer works so well is because it has spiral flutes that allow the reamer to advance through the king pin bosses with little effort and one straight flute for proper sizing and finishing.
It comes with three different undersized pilots for a perfect guide through the boss. All you have to do is determine the right pilot for your bosses and you are ready to attach it to the end of the reamer and begin. When you are finished reaming your king pin, be sure to check for proper fit by sliding the king pin through the bosses.
The third step is to bring your spindles up to the axle ends, being sure you apply a generous amount of grease to the spindle bearing. On the bottom of the spindle you will put a shim, then the bearing, and then another shim. I hold the shims and bearing in place by putting my finger through the brass bushing in the spindle while bringing the spindle up to the axle king pin boss.
With the spindle in place, slide the king pin through the spindle bushing into the axle boss and through the bottom spindle bushing. (Keep your finger in the bottom bushing while sliding the king pin down, to ensure the shims and bearing line up with the king pin.)
Install the bolt on the bottom of the king pin and tighten. Now that you have installed the spindles on the axle, bring the left front combo arm and caliper bracket up to the left front spindle. Install the two ½” by 1 ¾” long bolts through the caliper bracket and spindle into the combo arm using red Lock-tight. (I also safety wire mine just in case!)
On the right side install the steering arm by running two ½” by 1 ¾” long bolts through the spindle into the steering arm using red Lock-tight. (It‘s a good idea to use safety wire on these as well.) With both steering arms on install the tie rod.
I use a one-nut kit on my arms. Use a 3/8” thick ½” hole cone-shaped spacer on the bolt between the arm and the heim end on the tie rod.
To continue reading, advance to the next page.