Cam Benty
August 2, 2019
Contributers: Cam Benty

Performance seats come in a wide variety of designs and comfort levels. But beyond providing a comfortable place to sit, a proper seat keeps you in position when handling hard cornering and or extreme acceleration. Supportive seats are as important as any performance part you add to your car and are a most important "touch point" between you and the vehicle - even if its just your backside.

Our 1990 Mustang LX had already gone through a seat swap in the past, the owner having installed some other early factory Ford version. Unfortunately those seats had seen better days giving us the opportunity to step up to an aftermarket seat that would take us into modern day seating technology.

Our choice for the LX was a set of Corbeau GTS II that have been very popular for years but still delivers amazing daily driver comfort with "anatomically advanced seat design," according to Corbeau. They continue, "featuring deep and aggressive thigh and kidney supports" these seats are a dramatic step up from our current set of well-worn buckets.

Fabrication skills necessary
It should be noted that along with a wide variety of high quality, high performance seats, Corbeau offers a complete line of seat mounts and brackets to adapt their products to different types of vehicles, both stock and custom. In our case, Gutierrez had been instructed, by the vehicle's owner, to reuse the factory seat mount/tracks rather than go with an aftermarket system.

For that reason, Gutierrez needed to develop new brackets to connect the seat to the factory slide rails. The factory seat brackets had mounting points 14-inches apart, in all directions, making for a perfectly square bolt pattern. The Corbeau seats feature a bolt pattern that is more rectangular; 13-inches side-to-side and 11.5-inches front to back.

Ready for any challenge, Saul Gutierrez, of Gear Driven Automotive, has seen his share of these mounting issues and walked us through the fix using some 3/16-inch thick bar stock. Gutierrez created an "H" bracket that he then welded to the factory slider seat rails so we could retain the same seat adjustment system. For this reason, a MIG welder and some way of cleanly cutting bar stock is necessary, along with a sharp drill bit to make the holes in the metal for the seat bolts.

Final fit
After installation, the seats were tested by the best backsides in the business and received the thumbs up. In all seriousness, the seats provided a dramatic change from the earlier factory seats with great under-leg support and solid side bolster positioning that should prove to be great help in hard cornering. The cloth covering will be cool in the summer and warm in the cold.

A seat to fit every
The Corbeau GTS II line up (PN 20301) of seats are not only comfortable, supportive and good looking, but also come with an assortment of orderable options that make it all the more attractive for daily drivers or part-time racers.

Among the options Corbeau offers with their GTS II seat includes an Anti-Submarine Slot (to allow a center-mounted seat belt to pass through the front section of the seat for racing purposes), Lumbar Support and Seat Heaters for both the driver and passenger. For those vehicles with limited headroom, they also offer a Shaved Base version that will lower the seat within the interior.

The GTS II seat also comes in a variety of solid and two-tone colors and fabrics from Black cloth to Black leather with Grey Suede inserts. This allows you to tune the seat to match your interior in both style and purpose. Corbeau adds, " This anatomically advanced seat was designed with deep and aggressive thigh and kidney supports while still maintaining the "stock" look." From our initial testing experience, they're right!

Saul Gutierrez puts a little heat to our adaptor brackets to create a base for the new Corbeau seats.
Our classic Mustang seats were not the original units found in our 1990 Mustang LX, but similar to what you would find in 1987-1993 Fox-body Mustangs of this era. They were well worn and ready for replacement with a proper performance seat upgrade.
Corbeau's GTS II seats are a favorite with folks looking for a great daily driver seat with plenty of anatomical enhancements that provide extended side bolster shaping and added thigh and kidney support. The headrests are nicely adjustable to a variety of heights.
Most seats are attached to the flooring of the vehicle with four bolts, two in the front and two in the rear. To reach the front bolts, the seat has to be slid as far back as it will go.
The factory seats offer an electric lumbar support that will not be used with the new Corbeau seats. We unclipped the connector and taped it off to avoid possible shorting to other metal surfaces.
With the seats unbolted from the floor, they simply lift out of the car. The seat brackets have sharp edges that are often rusty, so be cautious to avoid cuts and scrapes.
Two springs help activate the slider mechanisms in the seat base. This large spring must be removed first. It will be reused so note its attachment points before you remove it.
This spring connector allows the seat tracks to move as one unit. Slip the retaining spring off of each end to release the wire and remove it.
Next, unbolt the seat tracks. There are four bolts that hold the tracks to the old seats.
We then measured the distance between the mounting points on the new Corbeau seats. The bolt holes are 11.5-inch long (front to back) and 13-inches side-to-side. This differs from the mounting points for the old seats which were 14-inches apart both front to back and side-to-side. We will need to fabricate an adaptor bracket to allow the seats to work with these seat brackets.
To create our adaptor bracket, we used flat stock that is 3/16-inch thick. We used two pieces of two-inch wide stock and one that was one-inch wide.
We determined that we needed two pieces of flat stock that were 14-inches wide that we would ultimately weld to the original seat brackets. We also cut a piece of one-inch wide flat stock that would fit between the two outer pieces to add strength to the adaptor bracket.
Gutierrez measured the size of the cross brace before cutting; square up your pieces before cutting or welding to make sure that all sides are even.
Gutierrez measured seven-inches from the end of the side bracket to set the mid-point within the adaptor bracket. This will be the location for the cross brace.
After lightly tacking the pieces together with a MIG welder, we test fit our adaptor bracket against the Corbeau seat to make sure it covers the locations where the mounting bolts will pass through.
Knowing that the adaptor bracket is the correct size and shape, we finished welding it up.
We mounted the original seat brackets back into the vehicle. This ensures that the seat rails are aligned within the interior and the seat will match accordingly.
After tucking welding resistant cloth under the seat brackets, we located the adaptor bracket in the exact location we noted earlier. Each corner was tacked with a MIG welder.
We then removed the finished seat mount system, which included the original seat mount brackets, and the new adaptor bracket.
With the new seat mount system out of the car, we could finally weld the finished unit without fear of setting the carpeting and interior pieces on fire.
This is what our finished seat mount system looked like with all welding complete.
Next, we measured the points where the Corbeau seat mounting bolts would pass through and drilled the holes; first with a smaller 1/4-inch drill to create a pilot hole and then the final 22/64-inch drill bit to allow clearance around the 5/16-inch mounting bolts.
Each of the seat mounts was sprayed with a protective black paint to complete the assembly.
Corbeau supplies these high strength bolts and we added the washers to increase reinforcement around the bolt head.
We reinstalled our two springs and tested the adjustment lever to make sure that seat tracks were fully operational.
Our new Corbeau seats are a huge improvement in appearance and deliver a high supportive feel when you sit in the car. Saul Gutierrez of Gear Driven Automotive puts the final touches on the install by positioning the seat belts.

 

 

Sources:

Corbeau
801.225.3737
corbeau.com

Gear Driven Automotive
Geardrivenautomotive.com
818.678.6500

 

 

Photography by Cam Benty