1968 gmc c15 coil spring conversion

[Aljohnsonii]

I wanted to keep my frame and didn't want to transfer all my equipment to another frame so I found a frame with coil springs a 1966 chevy c 10 swb with a 12 bolt rear end

Part list I used

34 - 2" grade 8 bolts
68-lock washers
68-washers
34-nuts
Coil spring brake hose (after hooked up looks like the leaf spring hose would work)
Shocks for coil spring(wanted new)

Now I went ahead and replace all the brakes,hardware and fluid since I already had it tore apart but that would be up to you



Big chisel and a hamer is recommended I found it a lot easier to nock the rivited off with it and a air chisel to know out the rivits

Reason I doubled up on the washers and lock nuts was because I wanted to make sure suspension would hold

First started by removing bed and drive shaft

[Aljohnsonii]

Jack the truck up and supported the frame right under the cab just talk enough to yank the tires off and in bolted the leaf springs and knocked the pot rivits off the upper shock mounts and rolled the springs out

[Aljohnsonii]

I pulled all the other parts off the truck
I pulled the spring support,the backing/stiffener and the track bar bracket. you have to use that bracket for which ever rear end you get. You can use a 1963 chevy setup (mounted on the axle tube) but it has a different track bar set up than the 1967-1972 rear end (track bar mounted on the axle housing)

[Aljohnsonii]

I had to cut the exhaust off uber the cab to mount up the rear control arms but you might not have to depending on what exhaust system you have.

I cut the support bearing bracket off the crossmember behind the cab to have clearance for the control arm brackets i saved mine because the horse shoe support bearing is stronger the the I beam bracket in the c10s I bolted the control arm brackets using the existing holes in the crossmember and loosely bolted the control arms to the brackets and left the springs attached

[Aljohnsonii]

The top coil spring bracket I took some measurements off the other frame where I cut the rivits off and took a 3/8 drill bit and marked my holes and drilled and bolted the top coil spring support bracket up and had to drill 1/2 " hole for the upper spring bolt I drilled that after I had the top bolted up and square with the frame that way the coil spring would be in a bind after I bolted the spring down

[Aljohnsonii]

I picked the rear end up and set one side on the control arm then went and done same thing on other side if doing with a helper can put on at same time but not needed and bolted up the rear end to the control arm and put the track bar bracket on the frame and marked what rivits to knock out and bolted the bracket to the frame and bolted up the control arm

[Aljohnsonii]

Now on my parking brake I have my cable for the rear end bolted to my backing plates on the brake system so I unbolted the backing plate from my rear end and cut the area where my parking brake bolted up and placed over the backing plate for coil spring axle and cut it and welded the parking brake bolts to the backing plate. ( my leaf rear end was a 10 bolt and the coil was a 12 bolt so the backing plate was different )

[Aljohnsonii]

Now the drive shaft I had to options measure the distance from my trans to the axle and go look in junk yard for a driveshaft or reuse mine. Since I had the horse shoe support bearing the bracket is to wide to mount for the control arm brackets so I cut the legs off of the bracket put it on the bearing off the truck and bent the bracket to the bearing and slid the bracket off the bearing and cut slits in the bracket and bent it to around the control arm brackets and welded the legs back on the bracket this took a lot of tacking and cutting but I reused the horse shoe bracket and two piece drive shaft

[Aljohnsonii]

If anyone has any questing pm me and I will answer the best I can I had to do a lot of research and trouble shooting because I couldn't find any direct info on how to do this swap hope this can help someone else wanting to do the same swap. This took me over a week to do due to weather and work but could be done in a weekend if done in a shop or was nice outside lol