Z31 Adjustable Control-Arm + Tension-Rod Combo Kit

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  • Regular price $344.00
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This is a DIY conversion kit for the front control arms, the entire bushing end of the control arm is cut off, and the receiver block is welded in place; then assembled with the rodend hardware. The main reasons for doing this modification are: replacing old and worn bushings, creating a more positive feel while steering or braking, and to reduce binding with more extreme caster settings.


The included double adjuster has opposing threads inside and outside, so unscrewing it will lengthen the control arm, tightening it will shorten the control arm. The jam nut supplied locks the rodend to the adjuster, while the jam screw locks the adjuster to the welded receiver block. The jam screw is accessible from underneath the control arm. The supplied rodends are nylon-kevlar injected race cromoly, which will take all the abuse, without any maintenance.


The installation of the weld-block requires first cutting the control arm at 90-95mm from the inner end of the arm (not the bushing center), though at less distance for a longer finished arm, exactly perpendicular to the bottom of the arm when resting on a flat surface. Proper care should be taken to clean and prepare the surfaces for welding, and minimizing heat transfer should prevent any warpage of threads. The weight difference with a converted arm is less than 150 grams. Note that the position of the endlink and tension rod mounting holes will change with length adjustment, some slotting or other modifications may be required.



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This is a 1988-89 model, rodend based tension-rod kit, to replace the fixed length OEM rod. By having length adjustment, caster becomes adjustable, something not normally possible on a Macpherson-strut setup. The caster effect can be important for high-speed driving, where the car will have more tendency to stay driving straight, and slightly more difficult to turn, but the 300ZX is primarily a touring car.


Since adding caster is one of the design criteria, the head that attaches to the control arm has a kink to it, of a larger degree than the OEM part. This will also help on vehicles that are lowered and don’t have a rollcenter correction kit, to return the control arm to it’s original position, without binding the balljoint.


The entire tension-rod is made of high-strength cromoly, except for the rodend spacers on the sides, those are stainless steel. The center adjuster is powdercoated black, but the rest is zinc plated. For weight savings, the adjusting bars are also gun-drilled.


The OEM tension-rod uses a custom stepped bolt to attach to the bracket, this gets replaced with the included 1/2″ bolt. This may or may not require gently reaming or filing the smaller of the two holes, for proper fitment.
When installing the rods for adjustment initially, it is recommended to only install one of the M12 bolts (with the nut almost tight) into the head, and to allow the tension-rod to rotate on the control arm, and pay attention to where the second hole now overlaps metal. That overlap has to be clearanced on the arm before the second bolt can be installed. Failure to do this when adjusting caster could introduce significant bending force on all the components, which then might become damaged over time, or even prematurely fail.