Editing HICAS - Removal (section)

==How?==

There are two ways, lockbars and the right way - replacing the bushes.

===Bushes===
The R31 rear subframe is supported at either end by thick rubber bushes. These bushes have hollows in them to allow the subframe to pivot. These need to be replaced. The cheapest solution is to buy aftermarket Z31 rear subframe bushes from the states and have them modified to suit. Noltec also make subframe bushes for HR31. The Z31 bushes will tap in while the noltec items have a steel shell and require a hydraulic press to install.
Urethane is solid stuff, and will remove all measurable movement in the subframe while still isolating vibration from the chassis and maintaining some compliance. It will easily last the life of the car in this situation.
Z31 bush mod: The bushes will fit into the subframe fine, but they are slightly too thick to fit between the chassis and the lower bracket. About 6mm in height needs to be skimmed off the top bush on a lathe.

http://www.noltecsuspension.com/popproduct.php?id=N92962&vhcid=536&brand=NISSAN&series=SKYLINE+R31++++87-90

http://www.thezstore.com/page/TZS/PROD/PSDC06D/23-4148

===Lockbars, why not?===
Lockbars are used for S13, R32/33 etc. why not for a HR31. For starters the system is completely different. The later model Nissans have a hicas rack (similar to a steering rack) that is attached to the subframe and pivots the rear wheels. This is replaced with a single lockbar, locking the wheels to the subframe, which is still bushed to the chassis. On a HR31, by replacing the rams with lockbars, you are locking the subframe to the chassis and eliminating ALL movement and compliance, and the subframe is not supported at the chassis pins as intended. The subframe is restrained laterally, but the sloppy up/down movement of the subframe with worn stock bushes remains. The result, all sideways rear suspension load is transferred to the actuator mounts, which will eventually lead to hammered out elongated bolt holes and distorted brackets, and you will then need to fit the bushes! do it once, do it right.

===How much? hard to do?===
The Z31 bushes from the states work out at approx $100 delivered, Noltec are 200ish. An aus spec pump and reservoir should be less than $50 from a wreckers.
Doing all the work yourself is inexpensive, but very time consuming, its a big job. The subframe needs to be removed and the ps lines in the engine bay are also tricky to remove with the engine in.