What is the difference between a shackle and a hanger?

no
not on both ends
the reason is obvious
the shackle allows the length of the spring to alter from bumps and loads
there is a fixed eye at one end and that positions the axle to maintain alignment
now if you had a shackle at both ends then the axle would be allowed to move out of alignment and cause handling problems
On tandem axles , the shackles are on the center pivoting bridge section but the other ends are still fixed eyes

bolt on
if you are referring to spring hangers-- the bit that the shackles and bushes go in ,--- welded on

The bushings inside the shackle (where the bolts go through) are worn out.

Try lock lubricant. Spray it sown around the shackle on both sides, and around the dial. Push the shackle into the lock body to unload the mechanism, then try to turn the dial again - if your hasp has the shackle under tension, it may drag the mechanism and keep it from unlatching.

old post.
this car is coil spring car on all 4 corners all are.
89 to 2004 and newer.
so are sidekicks and Vitara's . same car.
so why not just ask how to lower coil spring cars and not guess at parts name,
they sell kits for this and are not cheap.
why have low rider 4wd, odd that.
The only way to do that is shorter springs,
the car body fits on a real A frame,. so the body can not be lowered ever. nor can a frame,
only the suspension can be lowered.
only samurai cars (jimny) are easy to lower with leaf spring mods.
see? (apples and oranges different they are)
in the old days, kid would , TORCH the springs on coil spring cars.
and as the coils got red hot, the car settled, and the guy on the
oxy torch yells over to owner , this low enough?
fun to watch , no fun to drive,

undo the 2 small retainer studs from the pin-plate. Place a nut on the thread of the pin and do up partway Ensure that the vehicle is placed on stands with the wheels just touching the ground so as to relieve all tension in the springs. Hammer the nut on the pin . It will also help if you use a pair of stilsons on the plate twisting while hammering. The plate will move out revealing a large hole on one side . When the pin moves freely remove the nut and hammer on the plate. As to the front swing shackle remove both nuts and with a bar between the spring and the hanger hammer the plate and pins out. undo the spring u- bolts and remove the spring Note-1--- do one side at a time as it retains the location of the front axle for spring replacement. Note--2---Hilux springs are bad for sagging so have an extra leaf fitted under main leaf Note--3-- do not use eurothane bushes as they will crack the chassis in adverse conditions.

I dont have a torch either, I usually try to get a sawzall metal blade in there to do it, or use my small hand grinder and gring off the bolt/nut head. Mike

Shackles are pretty straight forward. Remove the existing bolts, change the shackles and reverse the procedure to install. Good idea to change the bushings while you're in there if they are at all questionable. It's best to do this with the CJ in the air, supported on the frame and use a floor jack under the axle to lift/lower the spring in/out of the shackle, one side at a time.

My son works for Ford and had a sign-on to get into their online service manual and was able to look it up for me. I knew he could do this when I posted, but he wasn't home at the time and I had my truck on a lift. If interested, the torque specs on the spring shackles are 98lb, both at the frame and spring and 66lb for the shock.

make sure shackle is shorter than one removed.