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toolman

Heavy Duty frame rails and connectors

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toolman    1

Orginially I was thought I could get away with repairing the frame rails.  But after cutting open the frame rails, corrosion made them unrepairable.   So rail replacement was  necessary.    After checking out the replacement floor pans and frame rails available, I decided to construct my own.   Normally one can get away without bracing the body to do the replacement.  But I

found some corrosion on the front of driver side rocket panel.   Could not determine how strong the rockers were without cutting them open.  I constructed body bracing inside the car just above the floor pan.   The bracing was mounted to the two lower door hinges mounts.  The outer seat belt mounts were used for the other side of the body brace.  1" square steel tubing was used in a crossing pattern to provide support for the floor pan.  I want to make it bolted in instead of just welding it .Construction took about

two days with all the fitting that necessary.

P1030413

  floor panel corossion

P1030416

   pics of removed rusted areas

P1030406

   lower door hinge mount

P1030403

    top view of the body bracing above the floor pan

P1030399

    close up view of door hinge mount

P1030396

   picture of repaired crack in rear transmission tunnel

P1030388

   frame rail rust

 

 

 

 

 

 

 

 

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grannyknot    11

I guess shipping is the real killer when bringing in stuff to the islands?  I would just warn you to only do one side at a time then just do the floor pan then when that is completed do the rocker, you could also bolt up the transmission mount to add a bit more stability.

Are you going to extend the floor pan rail so that it connects up with the sub frame in the back? Like the rail extensions that BadDog sells.

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toolman    1

Shipping stuff here is a killer!!   Replacement floor set (both sides) without the rail upgrade shipped here by Post was over $400.   I still plan to do only one side floor panel at a time even with the body brace.   You never know if you might need some additional measurements.   Can't get it if you cut up both sides.

My old transmission mount was removed when I first put Chevy 327 with Turbo 400 about 1974 or so.   I do plan to connect the front frame rails to the rear

ones.   I will beef up the front side of the rear frame rails as I was thinking about putting a whole independent suspension and narrow it.   But for now, I'll

leave the R200 differential in.  Also. I plan to upgrade the front frame rails for the LS3 motor.

                                                                                                                        Sunny

floor panel cutout 2

floor panel cutout

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toolman    1

Found additional rust in front left side rocket panel.   So I constructed additional bracing for the engine compartment.   The bracing of 1" x 1" steel square tubing connects the firewall with the two strut towers.  The bracing is necessary if corrosion is found in the engine compartment frame rails. 

                                                                                                        Sunny

P1030420

  rocker panel rust

P1030425

  firewall bracing

P1030423

  firewall bracing

floor panel cutout

  floor pan cutout

 

 

 

 

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toolman    1

P1030442

      firewall cut out--(note edges for patch are flanged)
 

P1030445

      exterior view of firewall
 

P1030446

      interior view of firewall
 

P1030447

      frame rail aligment
 
 

 

 

 

 

 

 
 

 

 

 

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toolman    1

P1030449

     I used a Sunex Toon #SX278C punch and flange air tooll.    There are various brand air punch and flange on the
 
market.  They are all basically the same.  The cut line must be straight as the guide depends on the cut line for straightness.  The resulting flange does provide
 
additional strength and leaves a flat surface when finished.
                                                                                                  
                                                                                                            Sunny

 

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toolman    1

P1030451

exterior view of firewall and rocker panel
 

P1030454

  interior view of firewall
 

P1030462

   Put a cardboard on a floor jack under the hole in the floor.
 This is used to create a template for sheet metal replacement floor pan.  The hole was traced with a flet pen.   Notes and measurements were written on the cardboard for reference.  Always add additional sheet metal as you can always cut the extra material off.  Adding material later is more difficult.   I replaced the floor pan with 20 gauge sheet metal( the original was 22 gauge stuff).  The pan consists of
both straight bends but have curved edges too.
 
sharedmedia=gallery:images:35465]  fitting and cutting the pan
 

P1030469

  aligning the pan
 
 

 

 

 

 

 

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toolman    1

P1030492

  Decided to strengthen the left side panel because of all of the corrosion.  So I added a 16 gauge piece welded to the side panel and firewall.
 

P1030494

  trail fitting the piece in place
 
 

P1030495

welding strengthening panel in

 

 

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toolman    1

P1030501

  corner opening left front of floor pan
 

P1030502

  using a bench vise slowly pound in circular pattern from inside to out.   Open jaws as you increase pounded area.
 

P1030503

  used the vise jaws to bend the top edge of pan
 

P1030504

  after matching the patch, tack weld patch to pan
 

P1030505

  check pan alignment then final weld patch

 

 

 

 

 

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toolman    1

Thongs are acceptable wear except when welding.

 

P1030508 (1)

   Hammer welding was used when both sides are accessible.  Must use a dolly on backside to hammer weld flat after welding with steel rod.  The advantage is the weld is flat on both sides.  Any welding on the Datsun 25 gauge metal requires a lot of patience.

 

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toolman    1
Posted (edited)

glue gun

  New method of attaching replacement floor pan to car body-two part structural adhesive.

 

P1030516

  After applying adhesive to both sides, the replacement floor pan and body must be held together for 4 hours to cure.
 

P1030517

  Cleco clips and metal screws can be used to hold panels together.
 

P1030519

Bottom view of floor pan showing screws and cleco clips
 
 
 

P1030522

  Using the structural adhesive to repair a small rusted area.
 
 
Tomorrow, the cleco clips and screwscan removed after welding the seams together.  The screw holes will
patched using the adhesive with a tooth pick and acid brush.

 

 

 

 

Edited by toolman

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toolman    1

P1030534

 

Bottom view of floor after welding and removal or cleco clips and screws.   As far as verdict on using

structural adhesive is still pending.  It works fine for small metal patches without welding.  However,

using it on parts that will be welded afterwards, there is some burning and smoke when welding.  So

although they say you weld after it dries, I think there is contamination of the welding with the smoke.

I have not had a chance to test the adhesive by prying a glued portion yet.  Will get back on that evaluation.

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toolman    1

P1030540

  corrosion on old frame rails
 

P1030538

  replacement frame rails
 

P1030546

  using magnets to support frame rail
 

P1030545

  aligning rail
 

P1030547

  rear frame reinforcement
 
 
   I decided to replaced the corroded  frame rails with 2 1/2" X 1" X 1/8" steel tubing.  These rails will run from the firewall to
the rear frame member.   They will add additional structural strength to the body.   Transmision mounts can easily fabricated
by attaching  crossmember to them.

   A 3/16" steel plate was welded to the rear frame to provide a strong location for jack stands.

 

 

 

 

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toolman    1

P1030548

  frame rail-rear crossmember to firewall
 
 

P1030549

  close up view

 

The frame rail extends from rear crossmember to engine firewall.  Checking out the front section of frame rail from firewall

to core support.   Wire brushing the area for close inspection-looking for signs of corrosion.  if I decide to go all the way, have to

add additional supports from strut towers to bumpers mounts and one between the bumper mounts.

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toolman    1

P1030555

  After cutting open the front rail where there was a small rust spot, this is what I found-more corrosion.   So I guess I have also to replace the two front frame rails.
 

P1030556

  close up of corrosion
 
 

P1030552

  picture of a Datum Line which is used a  reference point for frame work.

 

 

P1030553

  overall view of Datum Line
 

P1030558

  As of now, I planned to install a Chevrolet LS3 crate motor with T56 6speed manual
transmission.  This motor is rated at 430HP  but they now have a updated version of this motor rated at 500HP.  I waiting to complete the major bodywork before I order the motor.  Chevrolet might have a better choice in the future!
 

P1030557

  Description of LS3 motor

 

 

 

 

 

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toolman    1

  Those slotted holes in the front cross member are for an eccentric bolt that provides about one degree of camber adjustment.  At the time,

I had access to automotive wheel alignment machine so I slotted the hole while checking the camber.  Now days, everybody is going to slotted camber plates on the top of the struts.   This was done in the mid 70's when only aluminum eccentric camber bushings were available.  Good catch!

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toolman    1

P1030560

  right side floor pan template
 

P1030564

    redneck sheet metal brake-1

P1030562

    redneck sheet metal brake-2
 

P1030566

   floor pan sheet metal  shape template
 

P1030565

   test fit for floor pan
 
  I constructed a redneck sheet metal brake for making the floor pan.   Using c-claps, vise grips, steel
tubing and steel plates.  It did the job.  I made a sheet metal shape template to aid in creating the slope in the floor plan.  A narrow about 1" wide was hand bend to match the shape of the existing pan.  The
floor pan was then test fitted.  The floor pan will be trimmed and attached with cleco clips.

 

 

 

 

 

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