rusted seat bolts

[Luke_Healey]

I tried to remove the nuts on my seat bolts to get them up out of the car and I immediately sheered the front outter driver's bolt. Are these just replacable bolts?

I have them all soaking in PB Blaster, but the outlook isn't good for a peaceful removal of the nuts. The inner fronts both came off easily since they've lived most of their life soaked in motor oil /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

The two rears are some weird size, seemingly not metric, seemingly not SAE??? Somewhere between 1/2" and 9/16" or about 13mm-14mm perhaps??? I don't know, but none of my stuff was fitting them right. I rounded one of them with a 14mm socket and hammered a 13mm onto it without any luck making it budge. Of course, my nut breaker is too big and clumsy to get up under there to break the nut off.

Any help?? I am mostly curious if these are just regular bolts, or if they are studs on the seat rails?

 

[sparkydave]

Hi Luke, you are correct, I believe the rear attachments on the seat rails are studs. I had to take the seats out of my car, and several of the bolts (and studs) sheared. I ended up drilling out the remnants of the studs, grinding the heads flat, and replacing them with bolts. I didn't think the nuts were an odd size though, my SAE wrenches fit them and I just used 5/16" bolts to replace them. Good luck!

 

[zimasprite]

Yep, did the same thing here!

 

[Trevor Jessie]

Didn't some spridgets have welded nuts on the rear?

 

[spritenut]

The front bolts on the seat rails are 5/16 x 24 (1/2" wrench) but they are welded to the fronts of the rails and are thin headed studs. I have had to grind them off but I just welded new bolts in the holes and grinded off the heads of the bolts to match the old flat studs. If not the seat will hit the bold heads.
The rear mounts are 1/4 x 28 (7/16 wrench) bolts thru welded nuts on the floor pan. At least when new.
I have seen metric nuts/bolts used, hex head zap screws, and once the rails were welded in. POs do amazing things.

 

[blkcorvair]

Luke sounds like you may have stumbled upon a 7/16" thread size. Much more uncommon in the vast scheam of things but have seen them in other applications.

 

[racingenglishcars]

I believe the nuts were welded onto the seat rail on the outside. The inside had the nuts welded into the floor strengthener under the car. Therefore the outside bolts went in from the bottom, the inside bolts went in from the top. At least that's what I've seen in my limited time working on lbcs.

As far as I know, they didn't use BSF bolts. A 5/16 BSF would have a head between a 13mm and 14mm

 

[tosoutherncars]

Whitworth, I'd assume?