C20 Removing Springs from Rear Trailing Arms
 

Reconditioning the rear trailing arms on 66’ C20. First, both the U bolts holding the rear trailing arms to the axle, and bolt holding the coil spring to the trailung arm were rust frozen in the trailing arm.
The ubolts were cut to release them from the rear axle. Then used a press to push the remaining bolt through the trailing arm. About 5 to 7 tons of pressure, pushed the bolt through.

Still had the springs attached the trailing arms. The issue for removing the springs, is to remove the square 3/4” nut that holds them together. Located inside the spring, and down some. Also the 3/4” square nut has several indentions and cut outs, ( and it is not xactly 3/4”) that make using a wrench or socket difficult or impractable. Susgestion for removing the square nut, is to cut it using a air hammer with chisel tool ( sharpen the chisel tool to cut faster). It removes the nut pretty fast. Now the spring falls off the trailing arm (TR)
Lastly Used a press to push the remaining spring bolt out of TR.

Note: also used the air hammer with chisel tool to remove the front bushings in the TR.

Will post some more photos soon. The first two show springs and trailing arms attached, along with front suspension taken apart.

Re: C20 Removing Springs from Rear Trailing Arms
 

Additional photos
1&2).Photo 1 and 2 below shows what the nut weld to the bracket holding the spring to the trailing arm, looks like. These photos are from another truck. You can see the nut is odd shaped and mainly only a square socket may work. The nut is not a normal size.
The head on this bolt twisted off when trying to remove it, because it was frozen in the trailing arm.
3). The third photo shows this nut split by the air hammer with tool chisel. The air hammer can require a large volume of air to operate. Suggest checking the specifications on pressure and volume of air required.
4). Forth photo is the bolt removed from 66’ C20

Re: C20 Removing Springs from Rear Trailing Arms
 

More photos
1,2, and 3). Photos of the trailing arm front bushing removed with the air hammer chisel. It is removed easily, the air hammer vibrates it out. The lip shown in photo 3 is the area concentrated on.

4 and 5). Photos show the air hammer and chisel used.

Note: The air Hammer May take a couple of minutes to vibrate it out, and maybe learning curve on how much pressure to use applying the tool.

Re: C20 Removing Springs from Rear Trailing Arms
 

Those square bolts are suppose to stay on frame.

Re: C20 Removing Springs from Rear Trailing Arms
 

These nuts are not attached to the frame, they are originally welded to a separate bracket that holds the coil spring on the rear trailing arm. Maybe just
semantics. You can see the bracket in post 2, photo 2.

As noted in the first post, the bolts were frozen in the trailing arm. Their by they could not be unscrewed from the nut welded on the bracket holding the coil spring to the trailing arm. This is a suggestion on how to remove the spring.

If these bolts are not frozen in the trailing arms, great, unscrew them as needed.

Re: C20 Removing Springs from Rear Trailing Arms
 

Well it seems to me the best way would have been a acetylene torch and heat up the rusty bolts and nut when cooled it would have comt apart 🤫

Re: C20 Removing Springs from Rear Trailing Arms
 

In my case, not having a torch, I had to carefully drill out the centre of the bolts, then air chisel a bit in order to jiggle them out.

Re: C20 Removing Springs from Rear Trailing Arms
 

I am at the same stage as aotte1 with my C20. Have removed the front and rear suspension. Posting some pics of what my pieces look like. So will echo aotte1's experience. have a very clean dry no rust truck. My spring u bolts and through t arm spring retaining bolt were beyond removal and re use. U bolts and the spring bolt had to be cut. Will post on my rebuild page the de rust, bead blast and paint process and outcome soon. My pieces are turning out quite well.