John...I imagine you are thinking about the advice you gave regarding replacing the springs...right? I'm thinking the rear shocks may be too long Huh?
Still Not Quite There O.K. so go out with one gallon of fuel in it over some bumpy roads then add 40 # and if that does the trick you're golden ~ if not , add 5 ~ 10 pounds more and try again , remembering to neither fill up the tank nor run out of fuel .
Ha Ha... It's about to get me to that point though! I think I'll splurge for a new set of rear springs...in honor of Lakeroadster.
How low is your truck now at ride height? Sounds like it's stance is lower than factory stock. If you buy stock height rear springs you may end up with a slight "altitude adjustment". Measure to make sure the truck sits on the bump stops before the shocks bottom out. That may be why your other set of shocks went bad so quick, they tend to not like supporting the weight of the truck. You might also want to measure the angle of the shocks, if they are laying down more than 30 degrees off vertical they may not be working correctly. _____ John
I know everyone is tired of this...as I am. I let the 66 sit for a couple days and thought about the history of this issue. Thanks Nate and John for your advice. I asked a friend (a better mechanic) to come over today. We bounced on the rear bumper and the 66 bottomed out with a metallic noise! We unbolted the rear shocks at the bottom and let them hang. My buddy got under the truck and I bounced on the rear bumper. After a few bounces he said, "I see the problem...the lower frame rail is hitting the adjustable knuckle of the panhard bar and not allowing the shocks to work properly" (I had installed the aftermarket panhard bar to the Suburban rear end way back during the build). We cut out a 1" by 3" piece of the lower frame rail, re-bolted the shocks, installed the 70# weight I had made, and went for a test drive. All was fine. The ride is great. I'm keeping my fingers crossed. Thanks, Jim
I'll take a couple of the piece I cut out and the lower lip of the frame. I don't believe there will be a strength issue since the cut is only ...1" deep and 3" long.
Are you by chance running some very heavy duty shocks, or installed any Helix spring helpers?, or the hilux leaf spring helpers?
No...the shocks are Rancho 5000's which are not real heavy duty. The coil springs are original 66 Chev C10. I believe the problem was caused when I added the Panhard Bar to the rear end. When I welded on the bracket to the axle tube, I failed to account for the travel of the bar's adjustable knuckle (like a tie-rod end) into the lower frame rail. My mistake for sure.
I added years ago the spring helpers on my F250 and the guy torqued them to much and all it did was bounce. I had them loosen it some so they only engage after the bed sinks down 1 inch on a load being applied in the bed.
John...I tried several times to transfer the photos from my cell to the "puter" and it just ain't happening. Windows 7 is making me nuts! Anyway, the slice from the frame rail won't cause any problems.