8
2-56 x ½” SH
Delrin
Pivot Ball
CRC Pro-Strut
Front End
2-56 Red
Locknut
1 - Pop the delrin pivot ball [58] into the lower arm [59]. Place the arm on a strong table and push the ball
in with the back of screwdriver handle. Or preferably, you can use CRC’s 4279 Ball Popper Pivot Ball
Tool. Notice the “lip” of the delrin pivot ball is pointing upward. The diagram to the left represents a right
side lower arm. For the left side, flip the second arm over and be sure the pivot ball is installed with the
lip again facing up.
2 - Once the ball is popped in, insert the black 2-56 clamp screw [60] through the hole in the lower arm.
Thread the 2-56 red locknut [61] onto the black screw. Tighten the screw slowly, continuously checking
the pivot ball. When it begins to bind, back the 2-56 screw off a bit. The ball should be free to pivot with
just a bit of drag. There is no need to have this ball super loose, a slight drag will be just the right amount
of clamping force.
Check this fit after a few runs as the ball will wear and require additional clamping force.
Lip
1 - Install the upper A-arm mount [62] with the amount of Dynamic Caster desired. The options are 0, 5
and 10 degrees. The part shown to the right is the 5 degree version and is a good starting point. The 10
will angle down more toward the front of the car with the 0 being parallel to the chassis. The general
thought is the more Dynamic Caster, the more steering the car will have at corner entry.
2 - Locate the 4-40 x 3/8” flat head screws [63] and insert them through the lower arm [59], and then
thread the screw into the upper A-arm mount [62]. Be sure NOT to over tighten.
58
58
59
60
60
61
61
Bag F
Hinge Pin
Upper Cap
Clear Caster
Washer
66
65
67
1 - Break the mold tree from the upper A-arm [64]. You can clean up the mold gates with a hobby
knife or rotary tool.
2 - Locate the upper arm hinge pin [65] and slide it into one half of the upper arm. Locate 3 small
clear plastic caster washers [66]. Push the hinge pin through the 3 washers. Then continue to
push the hinge pin all the way into the upper arm.
If the fit of the upper arm on the hinge pin is tight, you will want to loosen the fit of the hinge pin in
the upper arm, not in the arm mount (pictured below). The upper clamp and arm mount need to
squeeze the pin so it doesn’t fall out. If the fit is tight and the arm doesn’t pivot freely, then work on
the fit with just the upper arm and hinge pin. Set the caster washers aside so you don’t lose or
damage them. This fit can be freed up by heating the hinge pin with a heat gun or hair dryer, or
you can clamp the hinge pin into a rotary tool and spin the pin in the plastic as if it were a drill bit.
The heat created will set the plastic to the shape of the pin without removing material and making
too much play in the arm.
64
65
62
67
3 - Now, install the arm/pin/washer assembly onto the upper arm mount [62]. Put the hinge pin in
the channel. At this point you can set your starting caster setting by moving these washers
forward and back. The position shown to the left will result in a competitive handling. Moving
some to the front will decrease steering from the center to exit of the corner. This helps smooth
out the car on extremely high bite tracks.
4 - Install the upper cap [67] with 4 black 2-56 button head screws [4]. The upper cap is the
“clamp” for the hinge pin. Be sure to tighten so that any gap is gone, however, do not tighten
beyond that point as damage can occur to the upper a-arm mount holes.
4-40 x 3/8”
Flat Head
63
2-56 Button Head
4
4
62
63
59
66
