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Discussion Starter #1
Hey all,

My '80 plain jane 'Camino has some VERY rusty lower-rear-control arms and I can see (and hear when driving) that those bushings are terrible. The lower control arms themselves are incredibly rusty and sloughing large flakes of material. I decided to address this problem sooner rather than later. I found a great deal on G-Body control arms that look quite pristine and have great bushings still, so I bought them. Before the change over, I thought I'd beef them up by boxing them. This thread will be a quick visual walkthrough of the process.

I purchased a small section of zinc-plated iron pipe and a 2" x 1/8" x 48" length of steel plate from Home Depot as raw material. The pipe will be cut into smaller lengths and welded inside the control arm to act as support to prevent crushing of the control arm once a rear sway bar is sourced (do not currently have one.) The 2" plate will cut to length and trimmed to nestle into the control arm, where it will be welded to create the box.
 

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Discussion Starter #2
Step One: Sway Bar Internal Supports

I'd eventually like to install a sway bar, cause I like the idea of the F41 suspension in general. To prevent the sides of my control arms crushing/collapsing when that happens, I'm pre-installing side-to-side supports.

I used a small section of 1/2" zinc-plated pipe which is cut to fit each of the four sway bar mounting points. These are loose fitted currently and will ultimately be welded into place.
 

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Discussion Starter #3
Step Two: 4th edge boxing.

The missing 4th edge of this control arm box is made with 2" x 1/8" steel plate from Home Depot. A 4 foot length is just enough to do both control arms.

I measured overall length by a detail on the arms. It's easier to look at the photos than to try to describe what I did, but there is an obvious line/edge in the stamping of the control arm, in the area of the bushing. My idea is to trim the plate stock to fit snuggly inside the control arm at each end while being surface tack welded along the majority of the length. Notches are needed at each of the plate.

Once properly notched, each end of the plate will nestle in nicely, supporting the bushings with their width side-to-side. The middle length of the plate is surface tacked to the control arm.
 

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Discussion Starter #4
The Pieces

You can see how the sway bar supports are nestled inside the control arm, and how the boxing plate fits.
 

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Discussion Starter #5
Pre-welding Prep

The edges to be welded need to be cleaned and weld-through primer prepped. I used a grinder with metal brush cup on the control arms and an Eastwood drum on the inside flats of the boxing plate.

Once wiped down clean, these surfaces are sprayed with weld-through primer.
 

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Use caution breathing that zinc - infused welding smoke. It's heavy metal toxic. I prefer to use the Weld Steel bar stock at Lowes or Home Depot that is not galvanized for these kinds of jobs.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk
 

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Discussion Starter #7
Great Advice

Rick!

Thank you for the timely word of caution. I will absolutely be welding outside, but this raises a few possiblities:

  1. Cut spacers from the remaining 1/8" flat stock as side-to-side supports instead of the pipe.
  2. Get a small length of weldable/black pipe to use.
  3. Continue with the galvanized and work with a box fan next to me to blow smoke away from me.
I think I will go with my first option. It uses surplus materials that are on hand. Thank you for looking out for me!
 

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Michaelj , Thanks for sharing the details on your project of boxing your lower control arms on your 5 th Gen Camino . I enjoyed the info and think other members and visitors will gain the knowledge to do it . I think I will press the " good reputation " button .
 

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Love seeing fab work. Makes me miss welding, before my vision went to crap.

Zinc poisoning ain't no joke. I made myself sick when I fabbed up a garden fork for the wife years ago. Felt like I had the worst case of flu ever, but only lasted a day.



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Discussion Starter #10
5th Gen Control Arms... Front? Back?

A question in my mind has been "Is there a proper orientation for the rear lower control arms?" In the sense of can you install a control arm 180° out of orientation?

The eBay arms that I purchased clearly show that a sway bar was previously used... and for the sake of my own personal anal retentiveness, I'm going to keep their original orientation when I install the inner spacers/supports.

After some quick and easy eyeballing with calipers, my conclusion is that the holes are all evenly spaced so that it does not matter which side is front or which is rear. The distance between the bushing bolt hole and the first hole in the body of the arms for the sway bar is the same on both ends. Also, the distance between the sway bar bolt holes on the far ends and the hole in the middle is also equal.

You can mount a 5th gen lower rear control arm in either rotational orientation. It does not matter!
 

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Discussion Starter #11
Let's get to the welding!!!

Full-disclosure... I'm not a welder by trade. I do a few spot welds here and there and then there is a looooooooong period of not welding. I'm not and expert. I'm not a pro. My welder is an Eastwood MIG-135, which runs on 120V AC. It's just enough for my current needs. Get it? I said "current" needs. HA! I'm hilarious!

Also, today did not go as planned. I thought I'd have the whole day to cut new internal spacer/supports, but that was not the case. So I forged ahead with using the galvanized pipe supports previously discussed. Here is what I did:

As previously stated, I set up outside and had a box fan which blew heavy metal smoke and fumes away from me. I also would hold my breath, I can go for about 1:30. So, I'd hit a spot or two on the galvanized pipe, then I would lift the mask and walk more than 20 feet away into fresh air before I took a breath. This made for slow going, but I'm confident that I did not breath the zinc-ladden fumes previously discussed.

The boxing plates were spot welded in regularly spaced pattern. Halfway through the second arm I ran out of shield gas, so I could not complete this phase.
 

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Discussion Starter #12
The feel of running out of shield gas...

I'm posting these photos just to show the difference that shield gas makes. I knew something was different as I watch these welds cool. The molten metal of the weld would bubble up and pop. There was also more flaring out while the weld was in progress.

I'm not a pro and I've never experienced this before... thought it might help other noobs understand the issue.
 

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Even our gm Body sheet metal has galvanizing which makes it a pain to weld. I power wire brush first & then again between the spot welds before I connect the dots. Cleaner metal welds better. I also lightly grind down the tops of the spot welds before filling in between dots so they don't act as heat sinks.
I got exhaust fans in my little home work area & an extra led light over my welding bench. Can see the fumes rise & get sucked away.

Got reading glasses lens in my auto darkening helmet. Can't weld if ya can't see from aging eyes.


Ran out of welding gas a few sundays ago, my 2nd tank I'm smart enough to have was at work.:sad: Grind that un penetrated crap down before resuming.

I have aftermarket arms I never put on yet. One issue with solid arms is binding. Some arms have swivel links. Recently saw ridetech has axle bushings that have swivels. Lance on pro-touring .com that has project 85 SS Barney in build thread recently posted & noted huge difference at the track he runs at.
 

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Hmmmm . I would think if you have a box fan blowing across the work area the shielding gas cannot be fully doing its job anyway. I'm not an expert welder either, but, I experienced poor shielding during hot weather here in Miami with a fan blowing on me and what I was welding.
 

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Simple answer here. Remove the galvanizing before welding. It's easy to do as it only coats the surface of the metal.

I blast the galvanizing off of parts in my blasting cabinet.
Or sometimes, I remove the galvanizing with my 1/4" angle die grinder and a Roloc disc at least 1/2" away from the area that I need to weld on.
 

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Discussion Starter #16
Yes, I hear you...

Hmmmm . I would think if you have a box fan blowing across the work area the shielding gas cannot be fully doing its job anyway.
Hey man,

I, too, considered that the box fan could mess with the shield gas. Here is what I did:

  1. Positioned the box fan so that it blows *just* above the project. The full force of air flow is pushing smoke that rises away. Very little is blowing on the actual weld.
  2. Positioned the control arm so that its own body helps to block the draft of the box fan at the weld site. The pipe inserts are located down/inside the bent form of the control arm. The fan was place slightly off to the side, so that air wasn't blowing directly down the arm's center channel where the pipe welds were happening.
  3. Boost shield gas flow slightly (from 20CFH to 25CFH) to help compensate for disturbed air.
Looking back, I can say that the internal welds of the pipe inserts to control arms acted and looked the way I'd expect. I did not use the box fan when welding on the top plates, and everything for that aspect went as expected until my last three welds. That's when I stopped, halfway through doing the top plate on the second arm.

I remember seeing the tank pressure gauge on the very low side, so I'm not surprised I ran out. I'm also pretty confident that I recognized the moment the weld material was not acting/looking right.
 

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Discussion Starter #17
Even our gm Body sheet metal has galvanizing which makes it a pain to weld. I power wire brush first & then again between the spot welds before I connect the dots.
I hit the mating surfaces where the top plate would sit with a wire cup. I simply could NOT clean the interior, where the pipe inserts would go, very well at all. As a result, I probably overcompensate/welded those interior/pipe spots.


Cleaner metal welds better. I also lightly grind down the tops of the spot welds before filling in between dots so they don't act as heat sinks.
My plan was to do all the spots/tacks and then wire brush and grind down before filling.



Grind that un penetrated crap down before resuming.
Absolutely! Thanks for the reminder.

One issue with solid arms is binding. Some arms have swivel links. Recently saw ridetech has axle bushings that have swivels. Lance on pro-touring .com that has project 85 SS Barney in build thread recently posted & noted huge difference at the track he runs at.
Your points about binding are appreciated. Hopefully this thread will live for others, so all aspects of the project are relevant. For my use, the good news is that this is not a severe duty application. I'm not racing on the street or the track and I don't think a 229 V6 will be pumping out the punishment! (HA!) I think I'll be okay. My '70 Chevelle SS396 has factory boxed F41s, which are essentially constructed the same way.
 

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Thank you for the write up!
Boxing is great on a drag car but not so good on a street car that drives on very hilly terrain. The reason the arms are so flimsy is so they can bend with the rubber bushings. Boxing them will limit the rear ends flexibility and make it bind quicker. I say this for the people who live in hilly regions like I do. Boxing those arms will cause a weird condition called snap oversteer.

The answer would be using a spherical joint like the Currie Johnny Joint or the Spohn Del Sphere joint in place of the rubber. That way you could have your cake and eat it too...
 

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Discussion Starter #19
So I've been thinking about what people have said about the issue of binding with boxed arms.

There was a time when my only car was my 1970 Chevelle SS396, and it regularly saw duty hauling me and my cats to/from Eastern CT from the NYC area. The Chevelle came from the factory with F41 suspension, and that means boxed rear lowers with sway bar. I used to come home a scenic way from visiting my parents over and through the twisties of Bear Mountain State Park in NY, overlooking the Hudson River. Even after replacing the original rubber bushings with graphite-polys all around, I have never felt anything weird like snap oversteer or binding.

I will continue to forge ahead with this project and see what happens. I tried to wrap up the welding on New Years Day, however my MIG electrode tip needs to be replaced and I need a new nozzle as well. *sigh* and I was JUST at the welding supply store to get shield gas.
 

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You can get a full set of rear tubular control arms with new bushings for under $250 and the comparison article that I read about said that the tubular is a more stable and efficient design than boxing the factory arms.
 
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