Z32 Rear Uprights Install

by Clawhammer

Overview:

While it is common knowledge that the S-Chassis cars and the Z32 share certain suspension components, it may be unclear as to what benefits swapping such pieces can provide. Z32 uprights are made from aluminum and therefore weight 7-8 lbs. less (unsprung weight) than their S13 counterparts.

This is complementary to the Z-32 5-lug swap, but if you would like to retain your 4 lug setup for some reason, swap your hubs over to the new uprights before you begin.

Difficulty: ***

Time: 2-4 hours

Cost: $50-$100

Tools:

-Impact wrench and sockets in 36, 27, 22, 19, 17, 12mm
-Ratchet
-Combo wrenches in 22 and 19mm
-Blow torch
-Liquid Wrench (or equivalent)
-Floor jack and stands

Materials:

-Aluminum Z32 uprights
–Conical ball joint seats (part #40173-33P00) and hardware (Hex Cap Screws, M12 1.25 x 80)
-Cotter pins (2x 3/32 x 1 (upright and control arm connection) and 2x 3/16 x 1-3/4 (axle nut)

Procedure:

==Collecting Your Parts==

Junkyard

If you’re going to a junkyard or something, save yourself some trouble and take the Z32 lower control arms too. If you don’t, at least make sure you get the conical ball joint seats off the ball joint on the control arm. In fact, my side by side comparison (sorry I don’t have a pic) showed that the S13 and Z32 control arms are the same so you could just bolt the whole thing in and skip a couple of steps. I’ll explain that later. Also grab the hardware that mounts the Z32 strut to the upright. Here’s a picture of exactly what to look for as far as the ball joint seat being stuck to the control arm:

Z32 Fork type lower strut mount

Somehow you’re going to need the Z32 fork type rear lower mount strut. Idealy you have a coil over set up that the manufacturer also produces for the Z32 that you can obtain and put on. I’ve read it’s possible to modify a Z32 shock to make it fit, but I didn’t take that route, and I wouldn’t recommend or consider doing this swap if you’re not going with a coil over suspension. In the side by side comparison above you can see the different mounting style for the struts on the uprights.

The difference:

==Getting to Work==

Begin by removing all of the unnecessary parts from your uprights. If you obtained yours like this, skip ahead. If not, you will be removing the brake shield (27mm nut – may be stuck!) and the ring seal. Below is a closeup of the seal installed and a comparison with an S-Chassis upright.

Chock the front wheels and support the rear of the car securely on jackstands, or support the whole car if you prefer. Remove the existing caliper and rotor. Remove the hub by pulling the cotter pin and the 36mm axle nut. Remove your strut by pulling the 19mm nut and bolt holding it to the S13 upright, then the 2x 12mm nuts in the trunk area.

Unbolt the iron upright by pulling all of the 19mm bolts and knocking it clear of the control arm (its pressed on). Then remove the 2x 19mm bolts holding the control arm in and pull them out. Now disconnect the torsion bar (goes through the hole in the right of the pic).

Once you have the upright and control arm unbolted, pull the entire setup off the axle. If it’s stuck pull harder or find something to pry with. Now that you have the entire assembly off remove the four bolts on the back holding the hub on and move the hub and brake splash shield over to the Z32 upright. If you’re using the Z32 control arm bolt the whole assembly back in the way it came out. If you’re going to reuse yours, then you need to get it off the 240 upright. Undo the nut (22mm) holding it to the upright but don’t remove the nut. Get it all the way to the end of the bolt so that it’s even with the end (flush) and give it a couple of whacks with a hammer to knock it out. After you go through this you’ll appreciate what those steel inserts on the Z32 upright do for you. Anyway once you get your control arm off attach it to your Z32 upright and then put the entire assembly back in.

Reconnect all the bolts, put everything back together (don’t forget your cotter pins), and move to the other side and repeat. When you’re all done go get an alignment.