TheSharpest
New member
Awesome build so far. Same motor swap I'm planning with my 77 K5.
Keep us updated
Keep us updated
GMC Jimmy (K5 Blazer) 5.3 Vortec 3 link coil spring build.
- Thread starter Wally'sJimmy
- Start date
Wally'sJimmy
Observer
Thanks! It's well worth the effort. I wasn't really excited about the LS swap at first just because they have been put in everything, but now I know why, they are good.
Wally'sJimmy
Observer
So why take a perfectly good truck and tear it apart to put coils in when there are excellent leaf springs out there from companies like Deaver and Alcan you ask? Two reasons (1) ride comfort and (2) to prove to myself I could do it. The first truck I built was a 84 k20, long story short, I wanted a rock crawler. We took 36" out of the frame, built a flat bed for it, narrowed the front end built a 383 with a 14 bolt, dana 60 and 37's and went wheelin.
I loved that truck, we drove it all over the state and had some great times. The truck was all leafs, Deaver long travel in front and Chevy half ton 64" spring in the rear. If flexed and rode great.
I was planning to convert that truck to long arms and coils, but life happened and I sold the truck, got out of 4 wheelin for several years until I bought the Jimmy. So I guess I look at it as an unfinished project, and you don't see many square body Chevy's with coils.
I loved that truck, we drove it all over the state and had some great times. The truck was all leafs, Deaver long travel in front and Chevy half ton 64" spring in the rear. If flexed and rode great.
I was planning to convert that truck to long arms and coils, but life happened and I sold the truck, got out of 4 wheelin for several years until I bought the Jimmy. So I guess I look at it as an unfinished project, and you don't see many square body Chevy's with coils.
Wally'sJimmy
Observer
Once I was committed to the project (mentally) I read everything I could about linked suspensions and talked with a few guys I know that had built baja trucks and buggies. Once I had the basic (and I mean basic) understanding of link separation, antisquat, roll centers etc. and my head was about to explode, I went to work. Now keep in mind I've been welding most of my life and while this isn't my first major project, I am NOT a "professional" fabricator, I'm just a guy at home with some basic tools and a head full of ideas. I did not design it with CAD software or even sketch it out on paper, I took the truck apart grabbed a tape measure an angle finder and started thinking, I work better that way.
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Once back apart I knew I had to address the motor mounts and crossmember. I wanted to raise the drivetrain but the only way I could would be a body lift. I ordered a 1" body lift and all new mounts from ORD and installed that first. That allowed me to raise the drivetrain and eliminate the spacers under the crossmember, I also made new motor mounts on the frame side raising the engine. At the same time I installed a shackle flip from ORD as well.
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Once back apart I knew I had to address the motor mounts and crossmember. I wanted to raise the drivetrain but the only way I could would be a body lift. I ordered a 1" body lift and all new mounts from ORD and installed that first. That allowed me to raise the drivetrain and eliminate the spacers under the crossmember, I also made new motor mounts on the frame side raising the engine. At the same time I installed a shackle flip from ORD as well.
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Wally'sJimmy
Observer
Sorry about the last one, not sure why the pics didn't show up. Let me know if the attachments cant be viewed.
My whole idea (at first) was to build a simple radius arm suspension. My friend has a Jeep LJ with a Rubicon Express ling arm kit and I was always impressed by it. I thought I would keep it simple and start there. To start I bought 2" .250 wall DOM tubing, 3" flex joints and bushings form Ballistic Fab and some left overs from a four link kit for a drag car I had laying around. I first made the mounting brackets that bolted to the frame and a new trans crossmember. The only brackets I bought were the link mounting brackets at the frame, upper and lower spring perches, and a track bar bracket on the frame side all of which I had to modify. everything else I made out of 1/4" plate.
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My whole idea (at first) was to build a simple radius arm suspension. My friend has a Jeep LJ with a Rubicon Express ling arm kit and I was always impressed by it. I thought I would keep it simple and start there. To start I bought 2" .250 wall DOM tubing, 3" flex joints and bushings form Ballistic Fab and some left overs from a four link kit for a drag car I had laying around. I first made the mounting brackets that bolted to the frame and a new trans crossmember. The only brackets I bought were the link mounting brackets at the frame, upper and lower spring perches, and a track bar bracket on the frame side all of which I had to modify. everything else I made out of 1/4" plate.
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Wally'sJimmy
Observer
At this point I was feeling pretty proud of myself, until I tested the movement. I had floor jacks on each end of the axle at ride height, lowered one of them and nothing, maybe a few inches. You see a radius arm set up has an inherent bind. To over come this you can use soft bushings, a wristed type set up like the early Bronco guys do, disconnect one of the triangulated upper links or build/buy a spring loaded upper arm similar to the Lock and Load just to name a few. Funny thing is none of it came up in my research (or I just completely missed it). This was suppose to be a simple project 
The bind bothered me so much that I scrapped the radius arm idea and started over and went back to the 4 link idea. The problem with the 4 link for me was clearance, I was trying to keep the truck as low as possible (3-4" lift) so to achieve that with a 4 link was very difficult, so that's where the 3 link comes in. I still wanted something I could live with everyday getting in and out of it, otherwise I would have lifted it much more. A 3 link was going to give me great bind free flex and the packaging under the truck was perfect for it.
To start I needed a good connecting point on the axle so a 3/16 3" wide plate was bent and fitted.
Then the frame brackets had to come back out and the link mounts shortened.
From there it was one piece at a time.
Then some quick movement tests.
The bind bothered me so much that I scrapped the radius arm idea and started over and went back to the 4 link idea. The problem with the 4 link for me was clearance, I was trying to keep the truck as low as possible (3-4" lift) so to achieve that with a 4 link was very difficult, so that's where the 3 link comes in. I still wanted something I could live with everyday getting in and out of it, otherwise I would have lifted it much more. A 3 link was going to give me great bind free flex and the packaging under the truck was perfect for it.
To start I needed a good connecting point on the axle so a 3/16 3" wide plate was bent and fitted.
Then the frame brackets had to come back out and the link mounts shortened.
From there it was one piece at a time.
Then some quick movement tests.
amgvr4
Adventurer
Looks good, I am interested to see what you ended up with. I had a similar progression on my D60 swap were I started out with a simple plan to do leafs and ended up with radius arms and coilovers. I found that the more you inboard the main pivots the better a radius arms setup works, and some of its inherent bind is nice on the street and acts like a sway bar. It will sure eat up some bushings though after two years of hard use!
Wally'sJimmy
Observer
Wally'sJimmy
Observer
I found the same thing, I originally set them up with very little inboard angle much like the new Ford's and Dodge's. In the pic I moved the axle brackets all the way out to the inner C's and it was much better but the tires would have hit the bars when turning. I could have made the setup work just fine for what I do, but I didn't want any binding (anal I guess).
Wally'sJimmy
Observer
Back from a little vacation to Jackson Hole Wyoming, what a beautiful area!
On with the build, Onc ethe main links were set up and after a few adjustments i could keep testing and checking the clearances.
Then I could add the track bar and steering for testing.
On with the build, Onc ethe main links were set up and after a few adjustments i could keep testing and checking the clearances.
Then I could add the track bar and steering for testing.
Wally'sJimmy
Observer
Once everything was was where I wanted it on the axle I could box everything in and weld it up.
Then I could weld up the frame brackets and paint them.
For a quick test my buddy had some Bronco spring laying around,
The springs I would be using were 5" long travel Deaver's for 78-79 full size broncos and F150's. They have a 300 lbs per inch rate and are 23 inches in length unloaded.
Then I could weld up the frame brackets and paint them.
For a quick test my buddy had some Bronco spring laying around,
The springs I would be using were 5" long travel Deaver's for 78-79 full size broncos and F150's. They have a 300 lbs per inch rate and are 23 inches in length unloaded.
Wally'sJimmy
Observer
Once welded and painted I put the axle back together, installed all new brakes and bearings. Now I could slide it under the truck for the final time.
The steering linkage between the column and the box was a challange. I used all Borgeson jounts (4 total) and (2) 3/4" heims for supports. I had to go threw the upper spring pearch bracket on the front side. After fighting it for a bit I got everything ligned up and opperating smoothly.
Once it was together I could not wait to test it on a dirt road, my neighbors were probably getting tired of me running up and down the alley anyway :smiley_drive:
The steering linkage between the column and the box was a challange. I used all Borgeson jounts (4 total) and (2) 3/4" heims for supports. I had to go threw the upper spring pearch bracket on the front side. After fighting it for a bit I got everything ligned up and opperating smoothly.
Once it was together I could not wait to test it on a dirt road, my neighbors were probably getting tired of me running up and down the alley anyway :smiley_drive:
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Wally'sJimmy
Observer
Some better pics after putting 35's on
Wally'sJimmy
Observer
GoPro vid of the suspension
A quick gopro vid the first time I tested it.
[video]https://youtu.be/goUK0VOP6UU[/video]
A quick gopro vid the first time I tested it.
[video]https://youtu.be/goUK0VOP6UU[/video]