Whats up TN, its been a while. I am here today to spread some information that is not so readily available, or at least of recent.
The ever so common drum to disc brake conversion is a very popular topic in our platform, and it seems there is two methods of attaching the GT-S disc brake hub to the Non-GT-S drum brake lateral/trailing/control arms.
The GT-S hub utilizes the same size bushings for all 4 of the arms going from the hub to the sub-frame (NOT the two arms going the direction towards the front of the car). Where as Sedans, SR5s, NON DISC cars have a smaller bushing and according control arm at the rear most position. This is reflected in red outlines in this attached photo.
This is where you will find recommendations to do one of two things:
A: Take the two rear most arms from the disc brake donor car. -OR-
B: Grind down the metal sleeve inside of the rear most bushing(red outline) to be able to fit the smaller control arm onto the bushing.
Either method is completely acceptable if you plan on running the stock bushings that are already present within the hubs/arms. The problem arises when you are pressing in NEW BUSHINGS. Bushing manufacturers (those readily available to our chassis in Polyurethane) state there is indeed a difference in the outer diameter of this rear most, outer bushing. Stating you have either a 28mm Bushing or a 36mm bushing. However, the INNER bushing, reflected in the photo in blue, on this arm is different as well. So people that reuse the existing bushings on their car have no issue with such. This is not reflected anywhere where bushing kits are sold, or at least that I am aware of.
If you plan on doing a disc brake conversion, and you are buying/plan on buying bushings for a disc brake car, you absolutely should grab the rear most arms from the donor car. Shaving the metal sleeve for width is much different than shaving rubber/poly to modify diameter of a bushing.
I am aware that there are probably 4 million threads on disc brake info, and I am also not here to argue if you found a website from 2001 that reflects this bushing difference, the bottom line is this info isn't easily available - now it is :laugh:. This is intended to be an aid to anybody so they can do this swap as problem free as possible. Two of the arms I bought for this conversion ended up being tweaked from some sort of an accident, so I had to find this out the hard way.
I will post more specific measurements upon request.