Many R31 owners choose to replace the front seats, because due to more than 2decades in service, the covering becomes worn and the springs/wadding in the seat construction sag, and the cost of repairing/reupholstering the original seats back to new condition, far exceeds the cost of buying new, aftermarket seats to replace them with.

The article below was written in 2006, and gives a good, detailed account of what's involved with replacing the original seats with aftermarket replacements. However, it is now 2020 and many Australian states/territories have adopted/are moving to adopt the NCOP (national code of practice) guidelines in relation to this type of vehicle modification, as defined in VSB14 section LK. In practical terms, this means the aftermarket seats themselves need to be ADR compliant, and the alterations be inspected by a certified engineer, to ensure the correct fasteners have been used in the attachment assembly ; a modification plate is affixed to the vehicle if it passes inspection that certifies the use of a specific brand/model of seat with the chassis VIN.

If you are considering doing such a modification to your R31, be encouraged to check with your local state/territory department of transport website to find out what compliance steps may be required.

What seats I used[edit]

These are the seats I installed. I chose them because the hole offset on them was 5mm different to the seat rails which allowed me to fit them safely and using the original seat rails (from what my engineer tells me I don't need a mod plate for in QLD) [*No longer the case in Qld since adoption of NCOP in 2013]. They are NOS brand and cost $379 (iirc) from autobahn but I got mine for $199 and $299 because I waited until they were on special.

The only down side to these seats if the way I have installed them it feels like they don't go back as far as they used to (by about 5 cm) so if you're tall maybe stop now or try something different.

What you need:[edit]

2 x NOS brand seats if you want to do it like me and not have much dramas
8 x spacers, which I made at work from a bit of scrap 316 stainless steel 25mm round bar. They are 15 mm thick. I feel it is a bit too thick, I think you could get away with 8 - 10 mm thick
8 x M8 30mm long HIGH TENSILE bolts I cant stress this enough use HIGH TENSILE for this remember you dont want the bolts snapping in an accident and sending you flying
8 x M8 washers
3 or 4 M8 spring washers for the hand brake
a round file
non height adjustable drivers seat rails

-and about 1.5 hours to do both if you don't mess around and sus it out before you start.

Here is the hard part - the spacers. One of my seats came with spacers but I already had made up mine earlier.

Change handbrake position[edit]

Now for the fun, remove the original seats, the center console and unbolt the hand brake from the floor.

Put the 3 spring washers under one of the bolts that holds the hand brake to the floor so it's moved over away from the seat and more vertical (this helps to clear the new seats when you install them), re-install the center console, and check the hand brake still works. If it doesn't you have fucked up something chronic. Note the new position of my hand brake.

Driver's side[edit]

Grab your driver's seat rails and on them at the front there are 3 holes 2 round holes and a square hole. File out the square hole with a round file so a M8 bolt can go through it do this to all the seat rails.

Trial fit the seat rails to the seats to make sure you have done it right and the holes line up.

Here's a photo of where the hole is that needs to be modified:

Now you have to file out 2 more holes on the seat rails the ones that bolt the seats to the floor pan. File out the inside seat rail on the drivers side about 5 MM so it moves the seat out and helps clear the hand brake.

Here's a photo of what it should look like when it's installed:

Now fit the rails to the drivers seat and install it into the car, and BAM a decent drivers seat is in.

Here's a photo of the seat rails what it should look like when you do it:

Passenger's side[edit]

For the passenger seat it's easier - the holes on the seat rails that hold the seat to the floor can be filed out 2.5 mm on each rail.

Outside seat rail side:

Inside seat rail on the passenger's side:

Compiled By:

Agent R31