Questions about stock shackles

[unrestored72Z]

What is the reason shackle studs are held by splines, vs just having a bolt? Not being able to strip the bolt head?

Does anybody make a stock shackle ready to go with bolts vs a stud?

Also, if bolts are used, can they both go the same direction so the lower can be removed without removing the fuel tank?

Thanks.

 

[CorkyE]

I've replaced shackles on my 79 and I don't remember studs being used instead of bolts. But, I'm getting old and it's been a few years since I did this.

I didn't have to drop the gas tank. Put jack stands under rear frame rails, floor jack under pumpkin, removed bottom shock mounts, took top shackle bolts out then lowered assembly enough to get bottom bolts out.

I replaced mine with heavy duty adjustable shackles and delrin top bushings - from Kieth at Custom Works.

 

[unrestored72Z]

Thanks Corky.
The reason I asked about studs is every replacement I see online does not use bolts.
Just going with stock rubber.

 

[Twisted_Metal]

As I recall... They aren't "studs".
The bolt heads have "carriage bolt" style" square bases which fit the square holes in the shackles.
(Allows you to use a single wrench to tighten them.)

 

[unrestored72Z]

Thanks Twisted.
Is there a reason they can't both go the same direction?
I can see a reason why they opposed, just wondering if that is required for something I'm not aware of.

What brand is your picture from?

 

[Twisted_Metal]

It's a pic I found on ebay... Unknown brand.
They are designed the same as the ones I installed on my car, many years ago.

The only reason they are opposed is due to the bolt head's base.
That design may be to prevent the bolt from wiggling and possibly loosening the nut?
(Just a guess.)

 

[unrestored72Z]

Regarding rear leaf bushings including those for the shackles.
Do rubber bushings come already packed in a sleeve like the photos?
Are the bushing for front of the leaf different than the rears?
I can't seem to find a complete kit for rubber bushings, piece meal only?
Does anybody run rubber any more, or just poly? I read so much about squeaks, for a casual cruiser aren't rubber preferred?

Thanks.

 

[FS87LT]

There IS a reason for the way GM and others do the front spring eye bushings. Sleeves for the bolt, as THAT CAN be a vehicle safety issue if the bolt hole gets enlarged, letting the front of the spring move around. Not good!

How the rear shackles are assembled could have more to do with the "time to assemble" on the assy line. Time is money, in that respect, as to the time allotted at each station on the assembly line. The more places where bolt torque is needed, too, the longer the assy time is, too. Fewer places for things to "not be done right" also means fewer defects/issues that can need to be looked at on the inspection line, too. One nut is better than more nuts!

Some people with polyurethane bushings might not be as attuned to squeaks as other might be. Polyurethane has less flex in it, so those who value more-precise handling tend to favor them over rubber, for that reason. Many hard-core road race vehicles can use solid metal bushings with no rubber at all. Poly is kind of in-between metal and the softer rubber.

FS87LT

 

[Twisted_Metal]

The front bushing is pressed into the spring.

The rears bushings inside the “barrel” in the frame and spring eye.

They squish a bit when the bolts are tightened to take up the sliver of space.

 

[unrestored72Z]

Thanks, I knew the rear barrel went inside the frame, but didn't know the fronts were pressed into the spring. Does that also mean they don't come out without a device?