47-59 Steering column transition thru the firewall?

[dsraven]

here are a couple of pics of that set up. I am also using the steering column from the donor vehicle and you can see how GM has put that together so only the shaft protrudes through the firewall. this rubber or urethane boot attaches to the rack just outside the firewall co it's vary clean and weatherproof. just some ideas. possibly some wings welded to the column tube or some winged clamps on the tube could be bolted to some reinforements from the dash to the firewall or, if you are running a firewall mounted booster and hanging pedals, you could make it work with the column bolted to the pedal bracket.

[leegreen]

How does that casting length line up with dash/firewall?

Not mentioned in this thread yet, but there needs to be some thought to collision damage, I think you don't want the bottom of the column mounted too strong, just located. Mine is in a sleeve it would slide in if the floor got pushed up. The factory mount of the '80s c10 column I was using when I built just supported the lower column with the edge of a 2 piece sheet metal & rubber grommet thing.
The slip joint of the 80s and 90s columns from GM I have seen is external to the column, inside the column is solid shaft

[dsraven]

I like LG's plans that tie the pedal box, dash and firewall together for a sturdy one piece member that bolts together, especially if you are prone to grabbing the steering wheel to help you get in. a plate on the firewall is a great idea to help support all that and not allow cracking. some ribbed (for strength) sheet would work well possibly and could be spot welded onto the inside of the firewall for a clean firewall look on the outside. if the edges were also bent at a 90 with a short lip that would make the sheet even stronger and allow for mounting other small things like wire harness retainer clips etc to keep things out of the way of the pedals etc. I have a task force truck and am using the bolt on sheet metal bubble that mounts the pedals, brake booster and master cyl, accel pedal, has a hole with a grommet for the steering shaft, and another for wiring, bolts up to the steering column and dash. it is recessed to allow a little more leg room inside and that gives it strength as well. all in all a pretty sturdy set up. I probably have more width on my firewall and floor than you do though.

[mobileortho]

A little late to the party but he’s where I am so far with my column.

[dsraven]

phunki, if filling firewall holes it makes it easier to do if you first clean both sides down to bare metal, then use a stepped drill to drill them all out to be round. then you can use an "unhole" sold by somebody like welders series, or you can make your own "unhole maker" by taking a piece of solid stock, drilling a hole in it the size you need for your unhole, then cutting a slice in the side of that piece, perpendicular to the drilled hole, so the slice goes in just a bit further than where the hole is drilled. this allows some sheet metal of the same thickness as your firewall to be slid into the slice and then a pin punch that fits the drilled hole can be used to punch a hole in the sheet metal. the piece that is punched out becomes the unhole.

[R&B51]

Phunki, dsraven is so right.
I’d read a bunch of times this site and his very advice on just enlarging the holes and using a couple size plugs to fill but only did it on larger ones when I did mine.
Decided to just throw copper block behind and weld-fill Al those 3/8-to 1/2” ones. Bulled through, grinder relatively smooth. All done, the few I tacked and then stitched plugs into look SO much better and didn’t heat, warp locally as others slightly did.
Kinda like a song plays on my “ZZ Top” Pandora station:
“Just 'Cos You Can Don't Mean You Should” by Joe Bonamassa
I’ll listen to dsraven and others next time.
Posted via Mobile Device

[Phungki]

Originally Posted by dsraven

phunki, if filling firewall holes it makes it easier to do if you first clean both sides down to bare metal, then use a stepped drill to drill them all out to be round. then you can use an "unhole" sold by somebody like welders series, or you can make your own "unhole maker" by taking a piece of solid stock, drilling a hole in it the size you need for your unhole, then cutting a slice in the side of that piece, perpendicular to the drilled hole, so the slice goes in just a bit further than where the hole is drilled. this allows some sheet metal of the same thickness as your firewall to be slid into the slice and then a pin punch that fits the drilled hole can be used to punch a hole in the sheet metal. the piece that is punched out becomes the unhole.

I dont have any issues welding up the hole. I'm just curios on what transition piece ppl have used if any. someone suggested a 2 piece unit that sandwiches the firewall between them. Probably going that route. seems sturdy

[leegreen]

I had to get under the dash of the '95 Sonoma that is my daily right now and the way the column is done reminded me of this thread.
for your consideration:

[dsraven]

thats what I was thinking with the pic of the envoy column, it shows how the column is short and hung from 2 spots under the dash. your pic is better, haha.