Lower Rear Shock Brackets: '63-66 vs. '67-72

[lakeroadster]

In order to not be hijackers this thread is a continuation of a discussion from this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=347169

Originally Posted by lakeroadster

The 60-66 lower brackets are superior in strength to the later design because it captures the shock on both sides.

Originally Posted by mcbassin

Hey, thanks for tweaking the model for the longer track bar. I appreciate the modeling skills. What are you using Solid Works, ProE, Catia? I use a few of these at work all the time. Mostly Featurecam for everyday use. BTW, I have to agree with you about the 66 back shock mounts much better design in my opinion.

Originally Posted by stich626

well as seen as the shock isn't holding up the truck (unless you run air shocks or coil overs.
the 67 up mounts are plenty strong

Originally Posted by mcbassin

I have seen several of the 67 up mounts fail. probably more to do with worn out shocks or loose mountingbolts? Usually the hole elongates or cracks out. You have to admit coupling the shock with both sides is better than one? It just seems like much more robust design. Probably took longer to assemble in the factory though so they changed it. Who knows.

Originally Posted by stich626

agreed,
but the mount wasn't/isn't the issue the cause is from lack of care..
like a emmissions converter, they don't fail, they are killed from something else up stream..

Originally Posted by lakeroadster

Really? When shocks fail they typically aren't as strong... they don't fail, get rock hard and break mounts. The point is GM went from a better design in 1966, to a weaker design in 1967. Look at shock mounts on new Chevy Trucks... they capture both sides.

And some of the aftermarket parts manufacturers are mimicking the weaker design in the shock relocation kits they are peddling. And they are selling them with shocks that are much harsher on suspensions, due to newer shock absorber technology.

If you use the truck to haul loads, the shock loads are more severe.
If you use your truck like a car the single mount will probably be just fine
Why settle for the weaker design? Or even worse, take of the stronger design and replace it with a weaker one?

Originally Posted by stich626

and if the shocks where replaced when their service life was up. there isn't an issue,,
shocks don't hold up the truck.. air shocks and spring helper shocks are what kills 99% of mounts, yes the older set up is better never siad it wasn't..
but the 67-72 don't fail because of an engineering point..
it's use'n shocks as springs (air or spring helper shocks) or a locked up shock (frozen or bent ) not the mount..

Originally Posted by lakeroadster

I guess we will agree to disagree.

Originally Posted by stich626

thats fine..
but I gotta ask, why do you think a load in the bed (say for sh and giggles 1000lb) adds load to the shock.. the wheel/trail arm/rearend isn't any heavier.
nor did the spring rate change.. shock is only controlling the spring that didn't change.. it's still so many lb per inch
load only lowered the travel some..
what am I missing..
yes if you add shock valving that is set up for a 4 by 4 or
to run a road course , then ya, it stress the mount more than the engineers ever though of..
never mind the fact they never engineered the trucks to last 40+ years..
just wondering your take on all this..

http://www.monroe.com.au/what-are-sh...explained.html

From the above link:
“Shock absorbers automatically adjust to road conditions because the faster the suspension moves, the more resistance they provide.”

That's what you are missing. the faster the suspension moves, the more resistance they provide.

A loaded truck will work the shocks more because, due to the load and the resulting rebound that results from the springs rebounding off bumps in the road, the truck bed bounces up and down more, with longer stroke, than when it is not loaded.

When you push on a shock, the faster and harder you push, the harder it pushes back... that’s how a shock absorber works. Thus a truck shock absorber will exert more of a load on its mounts when the truck is loaded.

John