Discussion Forum - Northstar Chevelle Club

That would be the correct way to repair that. Obviously, you'll need a good frame cut-off for this and I would consider going further forward to were the frame is boxed for strength.

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

These frames were symmetrical.
Most all dimensions were equal side to side.
If you can come up with a way to elevate body and verify all measurement through crosschecks and lengths side to side it would be the best.
Unplug wires, remove radiator and shroud, any linkages attached to body, and deal with brake system.
Remove ALL body bolts, lift and separate body from frame.
That is the easy part.

Most everything else is plumb and square.
Remember if you have a stiff coil spring it can preload the frame. (twist)

Blocking at torque boxes and confirm elevation on those inner corners.
Then verify elevations at front and rear frame ends.
Should be even side to side.
Cross check center between torque boxes, rear from suspension cross member to rear frame corners.
If all is square and level you should be good to go. Document all measurements.

Having body completely out of the way eliminates the need to compromise and deal with cramped access.
When frame people talk about "datum" they are talking about dimensions to an imaginary level line below frame. (floor)

A tram gauge is great for measuring distance both length and crosschecks.
Hanging frame gauges help confirm level (datum)
You can do 90% of this stuff with careful use of a tape measure.

Most of this fits in with what Mitch was alluding to.
Remember, most of the time it is better to take thing far enough apart for good access than to try and work around stuff.

Will post detail photos of Elky Frame we have in process tomorrow.

Karl

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?

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?

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

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

-- Edited by more ambition than brains on Monday 6th of November 2017 02:34:18 PM

Most of these #s are really close, except for the rear.
Still, little to worry about.
You can probably get the rear elevation almost perfect when fitting cross member.
Which side did you have to shim at the rear mount?

Did you crosscheck rear?
Are we having fun yet?

Karl

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?

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.

-- Edited by jim larson on Thursday 7th of December 2017 09:05:05 PM

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 

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.

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 ?

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?