1968 Pontiac Firebird Front Sub frame Rebuild / Restoration

I wanted to replace the body mount bushings right from the beginning on my car and detail and restore the engine
compartment. And if you have not figured out by now, I am a bit of a perfectionist. I have not ever been able to
do or build anything half-assed so the sub frame ended up getting stripped completely down to the bare frame,
then built back up properly. The welds on this sub frame from the factory were so bad I could not stand to look
at them. I often tell people I have seen grade 9 students that have never touched a welder before, make better
welds after 10 minutes of instruction than were done at the factory on these beautiful cars. I took lots of pictures
before starting to repair them and I still shake my head in amazement when I see them.
So here are my shots and comments about the sub frame resto. The removal, refinishing, and re-installation of the
upper and lower control arms are done on the front suspension page.

Here is what the frame looked like once it had been stripped of all attachments. The bodymount surfaces, which
are often in poor shape on these cars, were in very good shape. My other 68 had those spots extremely worn
and rusted out. They would have needed to be repaired or replaced.
These were in very good shape.

I had originally planned on just grinding all the surfaces but I was able to borrow/use a portable
sandblasting rig that my friend Scott had in his shop. It was a good industrial blaster. I found out
that there was nowhere to buy any blasting sand in my city so I went to our local Home depot and
bought a couple of 50lb bags of regular cheapo sandbox playsand. I stretched out enough hose to
get across the parking lot into a field where the sand would not be a problem. I wore a facesheild,
safety glasses, ear muff style hearing protection,and good quality respirator because I knew the
dust created from fractured silica sand is very harmful to one's lungs. I was shocked how fast
the first 2 bags of sand went through the blaster but it worked very well. 4 more bags later
(for a total of 300 lbs of sand) and all the crappy factory welds were laid bare. The rust and
old paint were all gone. It was a really hot day (more than 30 deg C) and I was soaked with
sweat in my coveralls and felt like I had sand in every pore of my body, but the frame was
ready to work on.

Here is my collection illustrating just how bad these welds were.

 

these are Burn-thru holes from the other side.

Excessive Splatter, Burn-through, overlap, undercut, cold lap, incomplete penetration, You name the weld
defect, it was there. I could use these welds for a textbook of what not to do.

After taking these pics, I went after all those weak little ratty eyesore welds with my grinder.
(Can you tell I was disgusted with them? )

Then I started replacing the welds with my own. I cranked up the current to the correct setting for
the metal thickness and used the same .023 wire and welded EVERY seam in the frame.

then I gave it a coat of the Silver Chassis Saver, then a second Coat of the Antique Satin Chassis Saver.
For some reason I did not take a picture of it after the silver primer coat was on, just after the black coat.
The chassis saver recommends if a primer coat is to be used to use the Silver because it has aluminum
flakes suspended in it. Why that helps, I have no idea but the manufacturer recommended it so who
am I to argue right?

because of the whole "UV" light sensitivity of the paint I gave it a couple of coats after this of
semi-gloss tremclad. It will protect it from going gray from exposure to light and evened out the
gloss of the Chassis Saver which I found a little uneven depending on how much I stirred the can.
Of course no pics of just the frame with the even spray coat but you can see it on the finished
pics that will be in the front suspension and front sheet metal pages.

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