Now the fun begins. All of the subassemblies are complete and ready toinstall onto the frame. The frame was cleaned thoroughly with xylenesolvent to remove grease and oil. Using xylene for cleaning can bedangerous; use it only in a well-ventilated area with no open flamepresent. We used a 3-inch orbital-style sander to remove minor surfacerust. Fortunately, there was no rust pitting on the frame.
Once the frame was clean, we applied Ospho rust preventative, which isgood for stopping rust and prepping paint. It can be applied with abrush or cloth, but don't leave any liquid. Rings or drips from rustpreservatives are almost impossible to remove. After applying thepreservative to the entire area, use a cloth to wipe off the excess.
Once the frame was prepped, we applied a coat of PPG DP90LF epoxysemigloss black primer to the frame. Add thinner to the epoxy primer forbetter flow and control of the semigloss sheen. The epoxy primerprovides durable protection without a topcoat.
The trailing arms, differential housing and cover, and rear spindlebearing housing pieces were powdercoated gloss black. All pieces wereblasted and powdercoated for $150, saving a lot of hard labor. Duringthis process, the correct-color topcoats were applied as necessary. Thepowdercoat base is durable and should prevent corrosion for many years.
The fun begins because the newly bought and cleaned suspension piecesmake assembly enjoyable. Before installing the differential, we put in adifferential drain plug for easy servicing. After the differential is inplace, the trailing arms can be installed. All of the bolts, washers,and nuts are being replaced. Split lock washers should always bereplaced because they lose their spring effect, diminishing grippingstrength.
When all the hardware is replaced, save the original bolts and nuts foryour NCRS buddies. All threads should be cleaned for proper tighteningduring assembly. An application of light oil during assembly preventsthread corrosion and allows proper torque.
We haven't selected a brake caliper, so we'll do the front suspensionbefore wrapping up the brakes. The brake rotors are aftermarket pieceswith a cadmium finish, so corrosion shouldn't be a problem for a while.We prefer to apply a high heat coating to the rotors for additionalcorrosion protection.
If aesthetics are important, wheel selection plays a role in the finishthat's applied to the calipers and rotors. We'll make a decision on thewheels before applying any color coatings to the brake pieces.
Parts are on the way for the front suspension except for the upper andlower control arms. We're considering Vette Brakes tubular A-arms. InPart 5 we'll discuss the front suspension overhaul.
Torque Specifications
Diff front mounting bracket bolts: 50 lb-ft
Diff crossmember to diff cover bolts: 60 lb-ft
Diff crossmember to frame bolts: 65 lb-ft
Axleshaft U-joint caps to diff bolts (inner): 35 lb-ft
Axleshaft flange to spindle flange bolts (outer): 65 lb-ft
Strut-rod bracket to diff mounting bolts: 45 lb-ft
Strut-rod shaft/shock mount stud: 75 lb-ft
Trailing-arm pivot bolts: 50 lb-ft
Wheel lug nuts, steel wheels: 80 lb-ft
Wheel lug nuts, aluminum wheels: 90 lb-ft
Axleshaft installation is simple. Make sure the universal joint cups arein place on the diff side. The outside axleshaft yoke uses French locksfor bolt retention on '63-'79 cars, but 7/16-inch split lock washerswork equally well unless you're looking for NCRS or Bloomington Goldcertification. | 
The VBP strut-rod mounting bracket positions the strut rods lower toimprove camber control. When installing the strut-rod bracket to thebottom of the diff, be aware of bolt length. If the bolts are longerthan 3/4 inch, they can pierce the diff case. Use lock washers and flatwashers with the bolts for correct bolt stack height. | 
A rough alignment can be done with simple tools before a trip to thealignment shop. Use a 24-inch carpenter's bubble level to check camberby placing the level flat against the tire. If the bubble is close tocenter, the car will handle safely. Improper camber can make a car feelscary. Use a tape measure to check toe-in. Measure from the center ofthe tires at the front, then do the same at the rear. A quarter-inchdifference in the measurements front to rear is safe and won't wear thetires excessively. Incorrect toe settings can cause tire wear as well,so checking the camber and adjusted toe is a must. |