Nothing Special's '71 Bronco

I decided I'd start a "project" thread on my Bronco.  It's not an '80 - '86.  It's not even an F-series.  But Gary seems to be encouraging people to have project threads that are a little bit afield of the origins of this web site.  So here we go.

I'm not going to start at the beginning.  If you want the entire story you can check out my thread on FTE.  In this thread I'll just pick up where I am now.

I did start giving updates on this project in the WHYDTYTT thread.  I covered changing the rear disks back to drums starting on page 152, and converting the vacuum assist power brakes to hydroboost starting on page 161.

edit to add:

I also have a couple of threads on vavations I've taken that include some rock crawling and trail riding in the Bronco.  Here is a trip to Ouray Colorado in 2018 and here is a trip to Moab Utah in 2019.

I should have a picture of it here!  This is from the trip we took out to Moab last summer, so it's pretty current.  There a black soft top that's usually on it, but not on sunny trail days!

Today I got started on my rock slider project.  Here's a picture of the back side of the passenger rocker. You can see why I don't think there was enough structure there to attach armor to the existing rockers!


Here's what I had been looking at on the outside


It looked even worse after removing the Gorilla Tape bodywork:


And after about 15 minutes with a death wheel I had the rocker off:


So I'm halfway done with one side already! (or maybe not quite half way)

By the way, here's a pic of the driver's side.  You can see that the aux gas tank fills the area between the frame rail and the rocker, with the bottom of all three at about the same height.  This is why doing something like putting nerf bars on isn't an option.

One thing I'd like a little help figuring out. I'm planning on getting a 4" x 4" square tube to weld in place of the rocker. Here's a pic with a wood 4x4 in place. Wood 4x4s are actually about 3.75" square, so a metal 4x4 tube will touch the inner vertical part of the original rocker that I left in place while still coming all the way out to the original outer line where I have the wood 4x4 in this picture.

The problem is the 3/4" step on the outside of the door sill (the metal above the 4x4 in this pic). I was planning on spot welding the inner side of the tube to the vertical inner rocker and the top of the tube to the door sill. But the outer step of the sill isn't as wide as I'd like, and the main sill is 3/4" above the 4x4. So I'm thinking I'll get a 3/4" tube and weld it to the top of the 4x4, and then spot weld the door sill to the 3/4" tube.

Does that seem like a reasonable approach? Or does anyone have a better suggestion?

First, I'm glad you started this thread.

And, I see what you were talking about with rust.  

On the 3/4" step, can you get a 3/4 x 3" tube to put there.  (I picked 3" as the guestimated width of the sill.)  That would spread the load out as much as possible, and I like that approach.

Or, can you get a 3" x 5" tube?  That way you won't have to add the 3/4" tube.  Something like this one?

Following, because there's always more to learn

I want 4" wide because that's what spans from the inner rocker to the outer rocker.  I need to go all the way to the inner to mount the tube, and if I don't go all the way to the outer the last ~3/4" of door sill won't be supported.  Also there will be a sharp piece of sheetmetal sticking out there to slice people's calves.  Alternately I could trim it off, but then the bottom of the door would be ~3/4" outside of the rocker which would look pretty schlock I think.  So I'm sticking with 4x4 tubing.

As to using a 3/4" x 3" (or so) tube, That's sort of what I'm thinking.  But...

I don't think I want or need to go the entire 3".  Stock the door sill is only supported by the vertical sheetmetal of the inner and outer rockers.  My inner will be spotwelded (many times!) to the 4x4, and the outer 3/4" of the sill will be sitting on the 4x4.  So I think it'll be much better supported than stock.  So the issue is just making sure that the 4x4 is well attached.

Also I don't really need the 3/4" piece to be tubing.  Not that I want it to be solid!  But the bottom side will be welded to the top of the 4x4, which will almost certainly be thicker wall than the 3/4" piece.  So I'm thinking of maybe starting with a 1x1 square tube and cutting one side off it.  The 1" should give me plenty of beef for the spot welds, and with the open side welded to the 4x4 it should have plenty of it's own beef.

Does that seem reasonable?

Yes, if I understand correctly, that seems reasonable.

Saying it another way, you'll cut the 1" square tubing and put the open side against the 4x4, welding it many times along its length.  So the top will spread the load and the sides of it are plenty strong enough to carry the load.  And the welds ensure it won't move.

Yep, that's the thought.

Gary Lewis wrote

Yes, if I understand correctly, that seems reasonable.

Saying it another way, you'll cut the 1" square tubing and put the open side against the 4x4, welding it many times along its length.  So the top will spread the load and the sides of it are plenty strong enough to carry the load.  And the welds ensure it won't move.

Could you get channel the right width so you don't need to cut the square tube and double it up?

Have to ask does that roll cage go to the frame?
I would hate to see the plates cut thru the floor, you did round the down side edges? and be useless as a cage.

It not hard to do, out riggers from the frame with a plate (rounded edges again) to sandwich the floor at all the cage to floor contact areas.
A dash & behind the seat bars keep the cage square around the driver / passenger, in racing we did not need to worry anyone in a rear seat but could add a removable cross bar across the back gate area.

In racing we X the halo bar back to the rear seat area and the fuel cell was within this X area for protection. With the dash & seat bars the X and 8 frame points you can do a half gainer and end up on the roof and walk away, the truck not so much
Dave ----

Or you could just use 3/4 box...

I think any 4" [] is going to be really heavy wall.

With the rust already there you're going to have to sandblast and phosphate, or something

Any oxide is going to vaporize the sheet metal before you get enough heat into the box tube.

"Welding a rusty razor blade to a boat anchor"

FuzzFace2 wrote

Could you get channel the right width so you don't need to cut the square tube and double it up?

I'm not sure exactly what you are asking.  No I can't get a piece of tube the correct dimensions to replace the 4x4 without adding something.  It can't be over about 3.25" wide at the top to fit in the channel, and it needs to be 4" wide below that to support the outer 3/4" of the sill and to more-or-less line up with the outer edge of the door.

And no I can't just make the door sill flat without the channel to fit against a flat tube.  If I cut the outer step off and raise that surface the bottom of the door will hit it.  And if I cut out the entire sill to lower the main part of it I won't have anything left to attach the replacement rocker to.

I could use 3/4" tall tube on top of the 4x4, but a 3/4" square tube doesn't spread the load out as well as a wider tube and it makes a smaller target to weld to.  And using a full tube adds material where it isn't helpful.  And I'm not going to double up the tube I cut.  I'm planning to cut one side off a 1x1 square tube, making it into a 1" x 3/4" C-channel and welding that to the 4x4 (unless you mean welding the 1" x 3/4" "C-channel" to the 4x4 is doubling up).

FuzzFace2 wrote

Have to ask does that roll cage go to the frame?....

I might get some "hate" for this, but I think that mounting a roll cage to the body is way under-rated.  Is it as strong as going to the frame?  Of course not.  But it will take a pretty bad roll to rip it up to the point where it's not protecting the occupants.  I think what I have is a lot stronger than any hard-top vehicle with no cage.  Clearly that's not saying it's good enough to meet tech inspection in a race, but I don't race.  It's going to hold up fine in an off-road flop, and will be better than my pickup in a freeway rollover.

ArdWrknTrk wrote

Or you could just use 3/4 box...

I think any 4" [] is going to be really heavy wall.

Not sure what you mean by "3/4 box".  My plan is about 3/16" wall, which would put the tube at about 45 lbs per side.  Not light, but it doesn't seem too ridiculous either.

ArdWrknTrk wrote

With the rust already there you're going to have to sandblast and phosphate, or something

Any oxide is going to vaporize the sheet metal before you get enough heat into the box tube.

"Welding a rusty razor blade to a boat anchor"

My plan is to hit it with a flap wheel and then with weld-through primer.  But I'm open to suggestions.

And I'm planning on drilling 1/2" - 3/4" holes in the sheetmetal so I can concentrate the heat more in the boat anchor, I mean 4x4 tube, and just sort of sneak the heat into the sheetmetal.  We'll see how well that works out...

I think what Dave was asking is if you could use a piece of channel that is 3/4" high and whatever wide.  That would keep you from having to cut the bottom off of a piece of tubing.  If you found a 3/4 x 3" piece of channel it would seem to fit perfectly.

Maybe you could slice 1 1/2 box tube down the middle and get more support, with 1/2 the labor and NO waste??

Yeah, a flap wheel isn't going to get rid of all the oxides in the pits because you'll grind right through.
Any of that is going to set fire to your sheet metal long before it will fuse to the 4" box

Blasting (with something that ISN'T an oxide) or burning it off with acid (reducing it) are the only ways I can see to get a solid weld there.

.187 seems a good compromise for strength and weight in this application.

Gary Lewis wrote

I think what Dave was asking is if you could use a piece of channel that is 3/4" high and whatever wide.  That would keep you from having to cut the bottom off of a piece of tubing.  If you found a 3/4 x 3" piece of channel it would seem to fit perfectly.

I'm not sure I want it to fit perfectly, then I'd need to make sure it's perfectly in place.  I'm going to have to weld the 3/4" tall piece to the 4x4 with the whole thing out of the Bronco and it will have to fit up into the channel in the bottom of the sill.  Having a 1" wide piece gives me plenty of room for error (and for weld filets).

Plus there's really no benefit to having that extra material to the inside.  Spot welding the 4x4 closer to its outer edge will give the welds more leverage.

ArdWrknTrk wrote

Maybe you could slice 1 1/2 box tube down the middle and get more support, with 1/2 the labor and NO waste??

True, but I have 1" square tubing left over from a previous project.  I think that'll work well enough, and it's free!

ArdWrknTrk wrote

Yeah, a flap wheel isn't going to get rid of all the oxides in the pits because you'll grind right through.
Any of that is going to set fire to your sheet metal long before it will fuse to the 4" box

Blasting (with something that ISN'T an oxide) or burning it off with acid (reducing it) are the only ways I can see to get a solid weld there....

I'll probably go with the acid then.  I don't have the ability to media blast myself, and I don't want to try to take it somewhere to get that done.

Nothing Special wrote

FuzzFace2 wrote

Could you get channel the right width so you don't need to cut the square tube and double it up?

I'm not sure exactly what you are asking.  No I can't get a piece of tube the correct dimensions to replace the 4x4 without adding something.  It can't be over about 3.25" wide at the top to fit in the channel, and it needs to be 4" wide below that to support the outer 3/4" of the sill and to more-or-less line up with the outer edge of the door.

And no I can't just make the door sill flat without the channel to fit against a flat tube.  If I cut the outer step off and raise that surface the bottom of the door will hit it.  And if I cut out the entire sill to lower the main part of it I won't have anything left to attach the replacement rocker to.

I could use 3/4" tall tube on top of the 4x4, but a 3/4" square tube doesn't spread the load out as well as a wider tube and it makes a smaller target to weld to.  And using a full tube adds material where it isn't helpful.  And I'm not going to double up the tube I cut.  I'm planning to cut one side off a 1x1 square tube, making it into a 1" x 3/4" C-channel and welding that to the 4x4 (unless you mean welding the 1" x 3/4" "C-channel" to the 4x4 is doubling up).

FuzzFace2 wrote

Have to ask does that roll cage go to the frame?....

I might get some "hate" for this, but I think that mounting a roll cage to the body is way under-rated.  Is it as strong as going to the frame?  Of course not.  But it will take a pretty bad roll to rip it up to the point where it's not protecting the occupants.  I think what I have is a lot stronger than any hard-top vehicle with no cage.  Clearly that's not saying it's good enough to meet tech inspection in a race, but I don't race.  It's going to hold up fine in an off-road flop, and will be better than my pickup in a freeway rollover.

No use the 4x4 but where you are saying to use the tube I keep thinking pipe.
You want / need to fill the void at the top and was thinking channel instead of a tube.
Now square tubing (tube) that would work again when I see tube I think pipe  

On the bar as long as the floor is not rusting at the rockers or rear wheel wells for the rear bar then I guess it would be ok on a flop if that is all it was going to do.
I also don't know how "crazy" it can get where you wheel but if you feel safe that is all the counts.
Dave ----

FuzzFace2 wrote

No use the 4x4 but where you are saying to use the tube I keep thinking pipe.
You want / need to fill the void at the top and was thinking channel instead of a tube.
Now square tubing (tube) that would work again when I see tube I think pipe  

I think I understand.  I'm not going to try to bridge that 3/4" gap with anything round.

FuzzFace2 wrote

On the bar as long as the floor is not rusting at the rockers or rear wheel wells for the rear bar then I guess it would be ok on a flop if that is all it was going to do.
I also don't know how "crazy" it can get where you wheel but if you feel safe that is all the counts.
Dave ----

The floor is pretty solid everywhere, and there's some structure (body mounts or something) in (I think) all six locations where the cage mounts to the body.  So I feel really good about it holding up to anything I throw at it off road, and definitely good enough about what might hapoen on the road.

edit to add:  The cage actually bolts to the body in 8 places.  The "A" pillar down-tubes bolt in front of and behind the "hat channel" that spreads out the load from the front body mounts.  The "B" pillar dpwn tubes (the main hoop of the factory roll bar) bolts on either side of a vertical piece of sheetmetal that ties the body "B" pillar into the body mount.  The kickers (part of the factory roll bar) attach to the top of the rear fenders.  So no other structure, but the curved fender is stronger than flat sheetmetal.  And the "C" pillar down tubes bolt to about an 8" square piece of flat sheet metal that's boxed in by the fender, the rear of the body and the side of the body on top, and by vertical sheetmetal going down at least 1" on all four sides on the bottom.  So it's all pretty well supported.

Not much progress the latter half of the week, but I progressed toward being able to make progress (if that means anything ).  I now have two 6' lengths of 4x4x3/16 wall tubing in my garage.  I don't buy steel often, so that was a bit of an adventure, but I'm set there now.

I also took a couple of 34" lengths of 1x1 tubing (probably 3/16" wall as well, but that's just by eyeball) and cut one side off to get a couple of 1x3/4 C channels.  This was the only actual progress.  I used a mill to cut the two corners off (one pass per side).  It took about 45 minutes of my lunch hour including cleanup.  No pictures of that yet, but I'll get some as I start getting the 4x4 ready to go in.

I also spent some time staring up from a creeper to figure out what I'm going to do with the structure that comes down from the "A" and "B"pillars.  Both are in the way of the 4x4, but I think I know how I'm going to cut and bend them so I can weld them to the tube and strengthen everything rather than weaken it.  Again, pictures will have to wait until I start actually doing something about it.

I also stared up at what the bottom of the fender needs to do.  Now it's bolted to an inner panel of the tub, but that's in the way of the 4x4.  So one option is to slice it off at the top of the 4x4 and weld it there.  But I'm not a good enough welder for that to end up looking very good, and I don't know that I want the fender welded to the body.  So I'm not stoked about that.

Plan B has promise though.  If I bend the bottom of the fender in at the top of the 4x4 I can drill and tap the top of the 4x4 (probably after adding some wall there to get more threads) and then I can bolt the fender to the top of the tube.  The only challenge with that will be making a good straight crease where there's come contouring along the curve of the fender (at the very front in the photo below, in-line with the bottom of the door).  But that's probably what I'll be trying to do.


And the last thing is that I want the rocker to stick out far enough to protect the door a bit.  I thought about getting a 6" wide x 4" tall tube, but I thought that might not look so good.  So what I think I'm going to do is put a 1" OD tube on it.  Below I've sort of mocked it up with the wood 4x4 and a 3/4" ID copper pipe.  The real version will be longer, going beyond the front and back of the door.  I'll also add a few supports in the middle.  And it won't be made of wood and copper!  Anyway, I found a local shop that can bend the 1" OD x 3/16" wall tubing.  They're working on getting me a quote, so again, progressing towards progress!

I fully understand making progress to make progress.  And, as Jim is wont to say, progress is good - even if it is just progress to make progress.

And I think I understand your plans.  They make sense.  But on the fender, I wouldn't weld it to anything.  I prefer bending it and bolting it.  And on the "extra threads" idea, is that close enough to the end of the tube that you could slip a nut in and tack it in place?  I'd drill and tap the tube, run a bolt in that, put the nut on and run it down snug, and weld it.

And I like your idea on the 1" tubing on the side.  Kind of a nerf bar.  But what about cutting a wedge out of it, bending it in, and welding it up?  Or do you like the curved approach better?

It won't be that far from the end.  I'd certainly be able to at least get in well enough to tack it.  But I'm planning on welding a plate on the end of the 4x4 to cap it off, and I'm not sure of it will work out better to do that before or after bolting the fender.  So that's certainly a possibility, but the details still need to be worked out.

On the bar, I think it would look more professional (or at least less amateur) curved.  But we'll see how the quote looks...