Rear seat brace vs bulkhead.

spongbob

Greasemonkey
Oct 1, 2022
129
74
28
Many of us already know about the rear seat brace some G bodies came with as well as various aftermarket ones. On another forum someone suggested that just riveting a panel of sheet metal from home depot would work just as well. I asked him about if the panel should have ribs or beads added to improve rigidity only for his reply to be a string of personal insults. Knowing that any future discussion with him was likely futile I wonder if a flat panel forming a bulkhead would work just as well as any of the different versions of rear seat braces?

There are four types of rear seat braces available.

The OEM brace which were spotweld in Grand Prixs and riveted by ASC for GNXs. As you can see these have big reinforcing bends almost like angle iron fence posts

View attachment 231450

Tubular aftermarket braces that bolt in are often considered the least good version of seat bracing. They are usually painted black and come in four pieces. Supposedly the tubes tend to develop stress cracks over time.

View attachment 231451

Tinman rear brace which is built similar to factory rear braces. This brace is constructed out of 14 gauge steel with shallow reinforcing ribs pressed into it to improve rigidity. The bottom corners are double plates spotwelded together, the rest is single plate. Tinman braces come galvanized which gives them a silver appearance. These can either be bolted, riveted, or welded in. As you can see this brace comes with mounting bolts. This is the version I plug welded in years ago.

View attachment 231452

Lastly another model I have not heard of until recently, the Turbo Farms rear brace. These are constructed out of 11 gauge steel which is thicker than the Tinman brace but lacks any pressed in ribbing . Though being a thicker gauge they may not require ribs. Also unlike the Tinman brace it comes predrilled for fasteners which is handy. The Turbo Farms brace comes powdercoated black instead of galvanized and can be bolted, riveted, or welded into place. Moreover, these braces come with 1/4 stainless rivets. There is an aluminum version also available.

View attachment 231453

There is also an old discontinued rear seat brace that was made by Kenne Bell years ago. I can't find pictures of it but it is supposed to be similar to the Tinman brace.


Here is a aftermarket rear seat delete panel or bulkhead for G bodies. Notice this professionally made one has reinforcing embossing stamped into it to add rigidity.

g-body-rear-seat-delete.jpg


A simple homemade bulkhead without embossing or ribs would look something like this generic picture. I don't know how rigid it would be without ribs or beads. I also heard that an unbossed panel like this can vibrate like a drum which can be unpleasent. You would need something like an English Wheel to add ribbing to a large panel.

images


Lastly, I assume its possible to use both braces and a bulkhead panel together which would probably add a lot of weight. To me it seems the OEM braces are probably the best option?
Having no English Wheel but having access to a couple 4x4" oak or hickory wood posts I suppose a matching groove and pinch ridge (for sheetmetal)could be fashioned possibly with some (side aligning devise) or pinhole ( required?) Aligning feature of whitch the whole die like structure with the panel in between could be pleated (chaneled), I have heard of wood being used "for fashioning' old car fender dies"(dyes).thinking of someone handy with a wood saw' and possibly router (or saw )or even a straight rod ( like a grounding rod? Could be aligned over the negative Groove in a say 28"(longer on the aligning end ?4' maybe ?)(ect)oak 4x4.. no really this could work even to the point of placing the whole stack of things under something heavy object like a bus, truck ,camper, house seal plate ( joust) ,large bearing press, were you can jack weight on the wood/ steel (sandwitch)ect hope this helps someone poor with some metal situations one offs"remember to work incremental in new fields of technique' also use test blanks if possible sorry no pics here lol"....
 
Last edited:
  • Like
Reactions: 2 users

pagrunt

Geezer
Sep 14, 2014
9,168
15,350
113
Elderton, Pa
I tried the UMI and the Hotchkiss LCA braces and was not able to fit mufflers on my Grand National or Malibu so the both got resold.
I've ran into the same problem with them & the Pypes 2.5" kit I'm using. The require the mufflers to be dropped about 2" down to clear. I steeped away from them for now. Might retry or use them on Jr.'s '79 since it'll begetting the Jegs 2.5" kit when the time comes.
 
  • Like
Reactions: 1 user

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,861
2,612
113
Galaxy far far away
Maybe the BMR LCA braces offers more clearance?
 

Tony1968

Royal Smart Person
Supporting Member
Jul 1, 2018
2,324
5,132
113
NW Indiana
I had the same issue, I ended up having the mufflers at a 20 degree angle to clear the braces
Same here. Maybe 15 degree tilt. Can never see it unless you are under the car and even then who cares!!!
 
  • Like
Reactions: 1 users

Tony1968

Royal Smart Person
Supporting Member
Jul 1, 2018
2,324
5,132
113
NW Indiana
Do you have tail pipes on it? Do you have pictures it?

Post 383 ish
 

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor