This project has been on my list since 2004.  At some point the rear frame  crossmember was replaced.  What they did is they just cut off the original crossmember  and slipped a replacement from another car over then ends where the body mounts are. Then they welded the replacement  crossmember in two spots to the sides of the original frame.    It looks like with a little grinding of the welds I can removed the replacement crossmember.  

What I was thinking of doing is then cutting the replacement to butt fit the frame and welding it back on.  Is that something that is do-able?  Photos to follow.

Here are are three photo’s.

I was considering doing this with the car body on the frame, making it more difficult.  I am thinking to remove the bumper/brackets, the gas tank, and the exhaust tail pipes.  Then loosing all the body mounts, at that point there is about an1 1/2" off clearance between the trunk floor/body and the frame.  I believe I can raise the body at least 1" more to give about 2 1/2" of clearance.  Do you think that will provide enough clearance?  Thinking of doing all this from the floor since I don't have a hoist, would that work or should I look for someone with a garage and a hoist.

Probably better to have the car on its wheels then being pickup by the frame twisting the frame in my opinion.

67ss wrote:

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Probably better to have the car on its wheels then being pickup by the frame twisting the frame in my opinion.

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 Yep, I have these 8" thick ties that I use for work where I need the weight on the chassis.

Yes Jim, removing all the parts you listed would be very helpful in this repair. When I replaced my trunk floor, we took all the body bolts out except the front 2 and jacked the body up 12". You wouldn't need to go that high, but it's possible for fitting and welding the top of the rail. If you did go that high, you could probably leave the fuel tank in and protect it with a burn blanket.

Thanks for the input Mitch and Karl.  I had the frame check for level back around 2005 when I first discovered this issue by a guy at Marion Lake Collision around 2005 and hung some frame gauges and said things were OK. I have alway thought the car was hit in the rear and the rear crossmember replace and maybe the frame tweaked a little.   Not familiar with the term torque boxes?  I will try to lift body as high as possible, just a little unsure of how to do that. Would it be best to remove hood?  Should I should remove the rear coil springs but  leave shocks?  Looks like this is going to be a real learning process.

I was going to try to lift the body with the front clip attached.  Is this possible?  In looking at info on the internet it seems that the front clip is usually removed.

Torque boxes (slang) frame areas at the inner corners in front of rear wheels or behind front wheels.

General location, bottom of front fender area, just in front of rear axel, right at trailing arm mounts.

As long as plumb and square perhaps???? mini lift body and patch in missing metal?

Thanks for the photo’s Karl. Am I correct in it looks like you had to do repair work on the passenger rear corner of the fram next to the 4 dr hit green 66?  Thats an El Camino frame and a little different than a coupe frame right?

Guys, after I finish removing the necessary things, like hood, radiator, etc,  in dropping the frame , I am thinking of setting the car up on 8” blocks, removing the mounting bolts from firewall back and loosing the bolts under the radiator support as much as possible. Building a wood  U channel to go under the pinch weld from firewall to just in front of rear wheels, with jacks at those four points and a wood block under the radiator support.

Then remove the rear wheels and Rear springs with a floor jack supporting the frame.  After that I hope I can lower the frame with the floor jack to allow access to do the repair.  Will this work?

Pretty much opposite of what I did...I jacked the body up on the rocker pinch welds with 2 floor jacks while the frame was on stands ahead of the rear axle.

I left the 2 front most body mounts in but very loose. I don't remember removing the hood or any of the front clip. We just watched the gaps and the fenders move with the body.

I don't see any reason to remove the rear springs as all the tension is in the pads and crossmember, not from the #5 body mount, behind the tire, back.

If it was here, I would set the frame up so the flat area of the frame you want to replace was level, front to back and side to side, if possible, no telling if it is installed correctly now. Measure and record the distance from floor to back-most body mount hole. Chances are good that they won't be the same side to side anyways, since this has already been hacked on. The front will have to line up with the existing frame and then you measure cross-ways for square and get new section level all around again. Measuring the bolt holes in the floor and making certain the holes in the frame are the same distance apart and the section is square and level are the most important aspects of this. Once it is tacked securely, I would lower the body and check fit and hole alignment.

Thanks again guys. Karl, I am a little unclear on where to put the paint sticks. Are you talking about the 12"x1"x1/8" paint sticks?  Do the sticks just go on the bottom of the rockers butted up to the pinch weld?  So essentially you are jacking under the rocker panel and no part of the jack touching the pinch weld?

jim larson wrote:

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Thanks again guys. Karl, I am a little unclear on where to put the paint sticks. Are you talking about the 12"x1"x1/8" paint sticks?  Do the sticks just go on the bottom of the rockers butted up to the pinch weld?  So essentially you are jacking under the rocker panel and no part of the jack touching the pinch weld?

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 Yes, I used a 2x2 between the jack pad and rocker.

Took demo pictures today.
Will post Monday.
Yes, what Mitch said, on the lower rocker edge, NOT on pinch weld.
Wood and tape is to protect paint.
I like the paint stick, because the jack pad wedges up into rocker. Less likely to slip off.
2x2 works well, however, any jiggling may cause it to roll off rocker, not ideal.

Either way, take your time.

Karl

Well the process has started. Removed rear bumper, tail pipes, and gas tank.  Front bumper and other attachments to body tomorrow.  More photos to show what I am dealing with.  No hurry Karl,I am slow in my old age.

One last question before I lower the fame or lift the body.  I am going to removed the rocker moldings as Karl suggested.  Removed the screws at the bottom.  Now it appears i must slide the molding up to release it from the clips that are mounted to the rocker and hold the molding on.

I am worried about scratching the paint.  Any suggested, like maybe slide a thin strip of plastic between the molding and the rocker?  Thanks,

Measuring and lifting pictures.

Please note elevation difference, loaded, with body, unloaded without body.

I am an advocate of blocking frame at four torque box corners, with wheels off.

Make sure distance to level floor is uniform side to side in those four locations.

Take four additional measurements at rear corners, side to side and rail just before boxed rear kick up area.

Cross check that same area cross member corners to boxed area.

Cross check should be uniform, elevations should match side to side.

If a variance, there may be a problem.

If not document and make re-installed, trimmed piece match those measurements.

Measure, measure, measure.

Document, document, document.

Karl

-- Edited by more ambition than brains on Monday 6th of November 2017 01:18:40 PM

Looks like the weather is nice today and tomorow, one last chance  to drive the cars.

On another  note i dropped the frame today.  Loosened the two front mount bolts and removed the rest. Duck Tape on the rocker, raised the car up and blocked the body at four positions, placed jack stands at mount position # 2 at 1” below frame. Lowered the car slowly with the floor jacks.

Took measurements, body sitting at 16 5/8 & 17 to bottom of bolt attaching fender support rod At front of car  he re31 & 31 @ rear extension flange.

Now  Frame:

top of frame @ mount #1 is 20 1/16 & 20 1/8

botton of frame @ mount #2 is 11 3/4 & 11 3/4

bottom of frame @ mount # 4 is 14 1/4 & 14 1/2 

top of mount # 6 is 17 3/4 & 17 3/4

top of frame @ mount #7 is  23 1/4 & 22 3/4

Car was hit in drivers side rear sometime in the past, so I expected some variation.  Her are two new photo’s.

-- Edited by jim larson on Tuesday 7th of November 2017 12:15:31 PM

Just finished the welding and most of the  grinding.  I added a little metal where it was thin due to rust.  I was thinking I should use a little bondo with fiberglass to smooth out the sides where I did the grinding.  Not sure of what to do, so suggestions appreciated.  First bondo/glass, then rust converter then paint.  Take a look at the photos.  What do you guys think?

Get a filler with fiber strands in it. No need to mess with the fiberglass separately. This may be available at a local marine store.  http://www.boatstore.com/evercoat-fibre-glass-100632-everglass-quart.html

ALSO, I would have the body bolted on the frame for the filler smoothing, as it will flex quite a bit from the mount right after the rear wheel to the last crossmember mounts.

Thanks for the recommendation Mitch, I see there is both long and short  strand fiberglass.  I plan to use the short fiber type.  Good though about the flex as that could cause a fracture of the dura/glass or Dyno/glass or Bondo/glass or ever/glass.  Quite a range in prices from about $12 to $28 a quart. Wonder is one is better than the other.

All the reviews I've read about the evercoat products is good. Bodymen rave about their rage products, so I would likely get that.

Maybe Karl has a recommendation ?

Mitch,

Go down there, pull a bunch more beads with the welder, grind and metal finish.

Seriously, adding more metal is a better option.

Try and replicate factory thickness even if you have to step back and section in a patch for paper thin perforated area.

All chemical filler products including the duraglass prefer a stable base.  (except those formulated for plastic parts)

Most all of the fiber based products work well and stick well.

Normally when I use them it would normally be a replacement for lead in seams.

Or, pits and deep fills such as badly warped seams that you can't get any straighter.

Base material.

The glass products are also denser and less likely to absorb moisture. 

Remember butchers use "Bondo" craftsman use "chemical filler"

Mitch's point about flex is valid.

Given our ages, and the use these cars get, consider Mitch's concern, try and make sure metal is as thick as possible and use the glass product you choose.

Highly unlikely it will fall apart in our lifetimes.

Karl 

My friend did lay down some metal whe re it was rusted and a little thin, I. Didn’t want to grind that area any more so that’s where I was going to add the glass filler just to smooth it out.  He jokingly said I could add a trailer hitch and haull a couple of 2500 lb bulls.

thanks for the responces  guys.

Decided to check frame and body at level, what I did was set floor jacks under differential lower control arm bushings and under the front frame brackets for the front sway bar.  Then set body down on body bushings except for the two most rear mounts.  Everything checked out good And level.  There is a 3/4” & 5/8” gap between the body and the rear crossmember. So I am thinking there will not be much if any flex in the welded area of the frame.  So I plan to add a little everglass or bondo glass and hope for no cracks or smooth out some seam sealer with lacquer thinner.  Here are photos of the rear body mount gaps.

Just about Ready for top coat, then put it back together.

What did you decide to do with the fuel line ?

Wish my partial was stamped that clearly. I can barely make mine out.

Is the frame assembly date still on the side, or was that removed with the sectioning ?

Date is still there, I think some frames are stamped with a part#; but neither my frame or the added section had any.  Trying to find a fuel line where the shipping is a little more reasonable. 

I might go with a OEM steel line as I can get it from amazon for$75 with free prime shipping.

All that’s left is to install rear bumper and top off the gas.  Notice bumpers were replaced by Northstar in 94.  Also see the stamp to indicate it’s a origional GM bumper. Can you tell where it was welded?