Access to Underside of Sub Rails

[dmaxweb]

I have a 30 coupe and I need to install backer plates under the sub rails for mounting the outer front seat seat belts. I've seen comments that you can just slide the backer plates in from the opening in the rear wheel well and then thread a bolt in from a hole drilled in the sub rail. Maybe I'm missing something. The opening from rear wheel well is way to small to reach into and hold in place to thread the bolt in from above. If I remove the rumble seat floor pan (just machine screws/nuts around the perimeter) will I have access to the underside of the sub rails?

 

[rotorwrench]

The sub rails are like an upside down U-channel. The major problem with access is the frame and/or body mount blocks if they happen to be in the desired location. With the frame being tapered and the running board aprons further covering access, it makes it very difficult to get where you want to go.

On Vince's site, it looks like the reinforcement with a welded nut was likely installed while the body was off the frame. A person may have to lift the frame to gain access. I wouldn't pull the body off but just lift it up enough to gain access. Maybe someone else could give more information.
http://www.fordgarage.com/pages/seatbelts.htm

 

[dmaxweb]

This is a view of the right side rumble seat floor area. The backer plate would be in channel underneath the location shown. It looks like once I remove the rumble floor I can slip it up into the U-channel of the sub rail.

 

[Big hammer]

Long skinny fingers can reach that area from the outside above the splash apron. A nut welded to the plate bolt down through the channel. Your going to need some help. If no long skinny fingers are available then raising the body a bit isn't a problem. Loosen steering column, body bolts on both sides jack up the body you will gain a inch and half. You'll need to remove rear fender bolts to running boards also, I think that's all I did to remove the splash aprons on my Tudor.