Roll Cage vs Rocker Box on '74 Blazer

[Bigb55]

Will a Roll Cage be sufficient enough to support the cab on a full vert blazer? or will the rocker boxes need to still be there.

My new to me '74 Blazer is fairly rust free. But I just noticed the cab supports that ran above the rocker box and contain the body mount nut are pretty much rusted away from firewall to the body mount. The boxes would need to be removed to repair the cab support.

It appears the rocker boxes (which are rust free) are the only thing holding the body on at that mount. From what I can see inside the rocker boxes the cab support is solid past the mount.

I understand the importance of the rocker boxers for structure. But they make access for bolting new seats, checking for rust, etc almost impossible. If they are removed would a roll cage be enough support?

 

[mechted]

As long as your roll cage grabs the firewall (higher is best) then it will stop the flex that the rocker box is designed to stop.

The cab mount is still important, and integral to the rocker box structure. You will need to fix that at some point. You probably have more rust under there than you can see, and it is a structural point of the cab that needs to be there. You could completely cut away the rocker box to gain access to your body mounts for replacement and then discover the rot goes farther. On mine: the rockers were trashed, but the mounts were salvageable with some reinforcements.



Couple threads to reference:
https://ck5.com/forums/threads/what-started-as-windshield-sagging-75-full-top.337271/
https://ck5.com/forums/resources/1973-k5-floor-replacement.81/
https://ck5.com/forums/threads/rocker-boxes.340167/#post-4080964

 

[nvrenuf]

As stated, the roll cage helping will just depend on design and how it ties to the body.

In my opinion, I’d do the roll cage and keep the rocker boxes. Remove the boxes for the body mount repair and seats then reinstall them.

 

[kgblazerfive]

Pull the boxes do a set of sliders and integrate it all together with the cage.

 

[Bigb55]

Pull the boxes do a set of sliders and integrate it all together with the cage.

would the sliders be the type that are welded onto the rocker panel? I am leaning towards building a tube framed rocker box replacement. Using the current rocker box and adding tubing where needed. Would that work similar to the slider?

 

[kgblazerfive]

I would pull the rocker box off / out / do some inspection may be more rusted then you can see.

Really depends on what you are building. If its a off road truck and the rockers are rusted cut them out replace with sliders weld the sliders to the frame. Street truck that you care what the body looks like I don';t think I would go that route.

 

[79rustyk10]

What's your ultimate goal for the truck?

For me that would determine a roll cage, vs fixing the rocker boxes.

 

[Bigb55]

What's your ultimate goal for the truck?

For me that would determine a roll cage, vs fixing the rocker boxes.

It's going to be a family cruiser. The rocker panels were replaced prior to my purchase and are brand new. The Rocker boxes are not rusted at rockers just the front body mount area.

Here's a pic of it

 

[Bigb55]

Started a "prelimary" tear down of the rocker box/rocker panel area. Turns out, the previous owner (or whoever he bought it from) only replaced the outer rocker panel. The inner one has been severely hacked up. Based on what I can see the inner rocker is missing the lower part that attaches to the outer rocker. Essentially the rocker box is not attached to the rocker panels at all. the only attached portions are the firewall, frame side and rear.

The body mount support (the one that attaches to the inner rocker and goes to the body mount) is completely rusted away on the passenger side. Whoever worked on it prior to my ownership, drilled in sheet metal near the rocker box front oval to hide the rusted support.

Furthermore, it appears there has been a 8"x5" patch on the floorboards on the passenger side. But instead of welding the patch in. the rust was cut out and the patch riveted over top. Luckily overall the floor pan is solid except for that wonky patch and a few holes at the outer rocker lip.

Why would someone replace the outer rocker and only hack up the inner rocker panel? why not replace both?

Is there a way to repair the inner rocker without removing the outer? I rather not have to repaint the rocker and grind the rear panel to find the seam.

here some sad pics for your viewing pleasure. I guess the good news is the rocker box is pretty solid, and I could rebuild it fairly easily. And the white paint is Summit White and easy to blend.





View attachment 347687

 

[mechted]

The problem is that the inner / outer rocker and rocker box are supposed to be spot welded together roughly every 8" along the length of the door... so you need to weld to your painted rocker.

Your options are to remove the outer rocker, replace the inner and floor support from above. Or remove the rocker box, and attempt to cut out and replace stuff from below. My guess is that you will end up cutting from both sides... because sometimes access just sucks.

It kinda looks like the riveted piece is just above the body mount. If that is the case, I would remove that next and keep exploring.

 

[Bigb55]

The problem is that the inner / outer rocker and rocker box are supposed to be spot welded together roughly every 8" along the length of the door... so you need to weld to your painted rocker.

Your options are to remove the outer rocker, replace the inner and floor support from above. Or remove the rocker box, and attempt to cut out and replace stuff from below. My guess is that you will end up cutting from both sides... because sometimes access just sucks.

It kinda looks like the riveted piece is just above the body mount. If that is the case, I would remove that next and keep exploring.

I will be purchasing all the repair panels and attempting to repair this properly. Outer rocker is going have to come off and Ill do my best to blend the paint.

 

[bp71k5]

Why would someone replace the outer rocker and only hack up the inner rocker panel? why not replace both?

nearly every evil previous owner does that. I was about to comment that it’s likely to be rusted a lot more than you think, but you dug into it before I had a chance.

that inner rocker is what does the work of supporting the body along with the rocker box and the parts where it bolts to the A and B pillar areas. FWIW, Those are likely rusted out as well.

bad news is you have to pull the outer rockers off and weld them back on once the repair work is done. I know there are several builds on the site that detail the process for 69-72 models and I’d guess the 74 is similar, just different parts.

 

[Bigb55]

Tear down started for passenger side repair. Inner rocker is 100% rusted away. Good news is the firewall, endcap for the cowl, fender, and so far it looks like the floor pan are "rust free".

Bad news, when I carefully sat the OEM hood on the ground and leaned it up against the wall. The driver side front corner bent in with the distinctive rusty crunch sound. The inner hood was rusted away. I'll probably just buy an aftermarket one.

At this rate I might as well just repaint it the OEM Grecian bronze from the RPO sticker

Also found a previous owner genius repair patch. It's a street sign. I might weld it in for fun. Lol

 

[mechted]

Brace your door opening before you cut any sheet metal. Here is how I did mine.

 

[Bigb55]

View attachment 347770

Brace your door opening before you cut any sheet metal. Here is how I did mine.

Will do. I am surprised it has not collapsed yet. The rocker box is attached but everything else is rusted away and offering no support.

I was also going to run a similar setup from the top bracket holes on the windshield to seat belt bolt holes. I don't have a hard top so want to make sure it has enough support.

Here is what I found under the Riveted in floor patch.

 

[mechted]

So I see: Inner and outer rocker, a floor panel, a floor support, and probably a kick panel (it extends downward into the rocker/floor support area) that all need to be replaced.

I used a combination of Tabco, LMC, and Amazon to order panels earlier this year... depending on which was cheaper/faster shipping/ available in the first place.

 

[bp71k5]

You might want to open up everything you are going to make sure you can see all the rust before ordering. Some places sell the whole front floor plan so if your rust extends all over the place, a whole panel might be easier. Might save you from have to return stuff.

But the trouble with opening up all the rust is that...it’ll be forever before you can drive it again. Decide now exactly how deep you want to go.

 

[Bigb55]

So I see: Inner and outer rocker, a floor panel, a floor support, and probably a kick panel (it extends downward into the rocker/floor support area) that all need to be replaced.

I used a combination of Tabco, LMC, and Amazon to order panels earlier this year... depending on which was cheaper/faster shipping/ available in the first place.

I placed orders today with LMC, Brothers, and Motorcity K5. Depending on who had the cheaper panel or in stock. The driver side is in similar shape so order Left and Right of everything.

I ordered kick panels just in case. I wont know until I start cutting stuff out if the kick panels be salvaged. Looking down from the cowl vent, where the floor pan meets, its solid. I might be able to grind off surface rust and treat accordingly. But I doubt it.

The hardest fix will be the body mount support and the front to rear cab support. Hopefully I can get them replaced from above. Trying not to cut the rocker box if not needed (its the only thing holding the truck together at this point).

 

[Bigb55]

You might want to open up everything you are going to make sure you can see all the rust before ordering. Some places sell the whole front floor plan so if your rust extends all over the place, a whole panel might be easier. Might save you from have to return stuff.

But the trouble with opening up all the rust is that...it’ll be forever before you can drive it again. Decide now exactly how deep you want to go.

I Ordered full front Floor pans. Figure I can cut them up as needed or order the smaller ones if its not that bad.

 

[Bigb55]

Has anyone used one of the replacement hoods? Brothers has a $200 dollar one that is similar to the 78-80 hoods and a "Premium" Hood that is 73-75 style for $500. I bent the corner of the OEM hood and found out its rusted pretty good underneath the bracing. Rather replace it then deal with a rusted hood in 5 years