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Fab Junky
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498 Posts
Discussion Starter · #1 · (Edited)
I decided I wanted to go away from all the electronic nannies of the new trucks so about a year ago I started looking for a clean Chevy Crew Cab truck to build as a replacement to my 07 Tundra. I wanted to go bigger with the tires, shorter with the wheelbase and have dual t-cases. Found a clean 88 crew cab long bed that was gutted but mostly rust free.


Got it home and gave back the bed of the truck, moved it in the garage and it fit by about 3"! Time to start cutting.


Got the frame lopped and chopped making more room in the garage and getting rid of about 3' of frame. Bed length will now be 5'.



Welded up the rear of the frame with a massive receiver as I plan on building a bed extender so the truck can still haul wood and stuff. Also want to be able to mount the winch in the front or back as the last time I got stuck bad, needed to pull out the back of the truck.



All this started in Oct-Nov of 2011
 

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Fab Junky
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498 Posts
Discussion Starter · #2 · (Edited)
C3 Rear suspension

I had decided at the start of this build that I was tired of all the bend center pins, axle wrap, and lack of spring adjustment with leaf springs so I was set on a three link or four link rear suspension. I had some novel ideas for the setup but decided against it for now and stayed with a traditional 10 degree lower, 45 degree upper setup. Mixed knowledge of desert trucks and rock setups for a low long arm setup that should work well at speed and still crawl well.



Rear suspension at compression



Rear suspension at droop. Setup for 14" coilovers/bypass shocks.



I kept the travel modest because Johnny joints can only handle 15 degrees of travel in each direction and 14" of travel at full articulation is right at 15 degrees with the link separation I am running.
Ride height

Articulated





Overhead
 

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Fab Junky
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498 Posts
Discussion Starter · #3 · (Edited)
C3 Front suspension

With the rear links done, it was time to move to the front and start a 3 link. Again I thought about some novel suspensions and bell crank steering but decided to keep it "simple" for a link suspension and go with a standard 3 link/panhard rod. This is by far much more complicated that the rear suspension because of the steering, engine, and front driveshaft all sharing the same space. I also decided to whack off the front of the frame where the frame is more like a roller coaster than anything nice to fabricate around. The stock frame goes up, down, in and out in this portion of the frame. I also was going to move the steering to inside the frame for tire clearance because anything bigger than a 37 will rub the steering box.













As I was designing the front suspension I originally was shooting for the longest draglink and panhard rod as possible leading to a system that when at full bump was horizontal and when drooped would have minimal side to side motion through the travel. This worked out to 1.5" or so of side to side motion as the axle moved through the travel. Then I drew up a system that had the track bar and drag link at 10 degrees up when at bump and about 15 degrees down angle when at droop with a drag link and track bar that were 10" shorter and the side to side motion of the axle decreased to 0.75", so angle of the system matters much more than length. Both still need to be as close to parallel and same length as each other as possible. The added benefit of this setup is that it also leaves room for the shocks (coilover & bypass) outside the frame. Another benefit is that the steering is basically horizontal at ride height as in these pictures.
 

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Fab Junky
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498 Posts
Discussion Starter · #4 · (Edited)
C3 steering

During the design of the front suspension I considered the popular Astro van forward steering box and a traditional rear steer IFS 1/2 ton truck box. I mocked both setups up and the traditional rear steer box won, the Astro box would have made engine mounting difficult. I also consulted Howe Engineering on the best setup for both crawling and going fast and they recommended their 4.5" travel ram to keep up with the steering, an 8" ram was out of the question, the ram would never keep up at high speed according to Howe. I have my doubts on the 4.5" ram but it will be easy to swap to a 6" ram if I have too. The goal when starting from scratch like this is to have the ram, steering box and knuckles all hit the stops at the same time to prevent steering damage. If one part of the system is bottomed while another part is still trying to steer farther, stuff is going to break. It took a lot of trial and error and a few different tabs on the pitman arm to get it right but I did succeed in getting the complete system to hit the stops at the same time.


 

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Fab Junky
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498 Posts
Discussion Starter · #6 · (Edited)
C3 Drivetrain

After finishing the front suspension design it was time to figure out the drivetrain. While it would have been nice to drop in a 6.0L, 4L80E, and a 4 speed Atlas, the $$$ would have vastly exceeded my budget. So I decided to stick with the one piece main seal, 4 bolt main 350 I got with the truck, a TH700R4 and the heavy but indestructable ORD NP203/205 doubler setup. The engine and tranny are cores and will be rebuilt later with all the good stuff in the tranny and hopefully the engine budget will allow a 383 conversion with vortec heads and a roller cam to make some big block power in a small block.
Ruff Stuff Specialties came out with a nice 350 engine mount system about a month after I fabbed these up from the stock mounts. I hate it when that happens.

It doesn't show in the pictures but I kept the front axle in the stock location but moved the drivetrain back 3" for better weight distribution and to give the front driveshaft a little more length. The cab will be moved back 3" as well to improve firewall clearance that is in short supply on this vintage Chevy when building around a 40" tire.

Drag link/track bar to crank pulley clearance is very close but it only needs to just clear. Later when I did the shock mounts I ensured there was sufficient clearance at bump and articulated positions.


A bit of luck but the very tight axle truss saved the day with oil pan clearance, everything is very close when the goal is a low cg that still has good bump travel.


 

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Fab Junky
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498 Posts
Discussion Starter · #7 · (Edited)
C3 T case crossmember

With the motor mounts completed and the general location of the driveline locked in it was time to make the transfer case crossmember. The goal was maximum clearance but still keep the driveshaft angles sane. the rear yoke is 3 degrees down like stock resulting in the front being 3 degrees up. I plan on using a 1350 CV on both ends. It was way, way, way easier to do all this with the cab sitting up on the rear of the frame than trying to do this on the ground under the whole mess.


While building the crossmember I mocked up a front driveshaft to hopefully make sure I don't cause an interference between the front driveshaft and crossmember. Also the front axle needed to be at full droop for this mockup.


 

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Fab Junky
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498 Posts
Discussion Starter · #8 · (Edited)
C3 Front accessories, steering shaft and other misc stuff

While I tried to get the links to clear a 40" tire at full lock, I failed, the tire rubs a little bit when at lock. I cannot afford 40's right now so the 37's I plan on running won't be an issue. Thanks to my friend who has loaned me the 40 for this whole build.


Help from another friend with the front drive setup let me finish of the steering and again everything just barely cleared after I notched the frame.
 

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Fab Junky
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498 Posts
Discussion Starter · #9 · (Edited)
C3 Cage

The goal from the beginning was to make a "unibody" out of the crew cab. trying to cage a truck and keep everything isolated is a PITA and ends up being a rattle can anyway so I cut all the body mounts off the frame right away because I was going to move it back 3" anyway for front tire clearance. Thanks to the other Chevy guys on Pirate who highlighted this problem in their build threads. The last truck I welded up solid (cab/frame) ended up quieter after being solid than when on body mounts. This also allowed me to gain a bunch of strength by having a limited "tube" chassis to reinforce the stock frame. I also skipped the PITA process of plating up the entire frame because the tube chassis cuts out all the flex. Even though the rockers were not rusted out, I cut it all off and bobbed the doors to the bottom of the door hinge to make the beast not quite so beastly on the trail. The rockers may not have been rusted out but they were full of 3" of dried up mud. Did I say I hated welding sheet metal....

The goal is to keep this as my truck for work and play (ok, mostly play) but that means keeping AC, Heat, and defrost. Stock dash got nixed so I could keep the cage tight to the body and keep it from being a knee buster.

Thanks to my cousin who pulled an all-nighter driving here from OK to help me knock the cage out over Memorial weekend.

I ended up giving the cab about a 1" body lift to clear the dual transfer cases. I went with the 205 rotation that levels it with the 203. Flat would not have worked and would have meant a lot of floor cutting and might have caused serious front driveshaft issues.
 

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Fab Junky
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498 Posts
Discussion Starter · #10 · (Edited)
C3 Expedition Flatbed

With the cage knocked out it was time to make the connection to a "flatbed". I really like my flatbed on my Tundra and decided to keep the same theme on this truck. Gas and spare flat under the bed for a lower CG and the nice flat deck to load gear on. Cage, headache rack, and shock mounts are all integrated in the bed structure.





 

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Fab Junky
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498 Posts
Discussion Starter · #11 · (Edited)
C3 Finishing the "tube" chassis

With the flatbed done, it was back to the front for the front shock towers and front clip. The 40 doesn't really fit in the stock wheel well.

I really didn't want to use fiberglass fenders or just hack up the wheel well opening so I decided to do a bunch more sheet metal welding and use two fenders to make one.


I'm no body man but I was happy with the result.



I made room for the vacuum boost system which I plan on running for now but with room for this, hydroboost will easily fit.



 

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Fab Junky
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498 Posts
Discussion Starter · #13 · (Edited)
C3 seat mounts and a few details

This is it, up to date with where I am at this week. Finishing up the front shock tower truss, seat mounts, more dreaded sheetmetal welding for the shifter boot plate and sealing up the rock rails and flatbed.







That's it for now. Need to sell the Tundra soon or the progress is going to slow way down. Axles are fully welded and under the workbench waiting for gears and lockers, links are all tacked together and waiting for welding by a friend with a weld positioner. I plan on working on the dash next and then the radiator/fan shroud mounts.
 

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Premium Member
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7,252 Posts
This is going really nice.

One thing that I learned on my is; that those ORD shifters are a real PIA to reach when strapped in. I bent them to reach more but still not ideal. Your in a better position to remount them, you have an auto trans.

The "unibody" idea is the SHIT! I love it. I like the plating on the bottom of the doors and fenders too. Maybe think about plating all the way up to the body line on the C pillar(rear of cab). I feel like that is the location that gets a bunch of abuse. And I like the stretching of the front fenders. I did the same thing on my 92' Dodge, 6" stretch to clear the 37's and stay low.

One more thing why the Johnny Joints? And not 1.25" heim joints?

And one last thing I love the bypasses( I think that is what they will be) and the coil overs. Total control.:smokin:
 

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you do nice work. subscribed.

so what are your plans for the truck? what kinda wheeling and such.

how long is that wheelbase, 135 or more?

Edit:
i dont like the hydro assist at all. in fact i hate it.
i guess you arent worried about the extreme stress the passenger side knuckle will see due to the ultra high steer mount you built.
nor do i like the shorter drag link and panhard due to mounting the box inside the frame.

sorry but this is pirate, and everyone thus far is swingin from your nuts for the work youve done. so i had to be the first douche :flipoff2:
 

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Fab Junky
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498 Posts
Discussion Starter · #20 ·
ORD shifters, wheelbase and such

Good to know I'm not the only one that thought the shifters were way to far to the right. I plan on heating them and bending them just above the shifter boots to keep the sealing good. Wheelbase is a nice short 132", just kidding that is still really long for a crawler. I plan on using the truck for all types of terrain from fire roads to sand washes to medium crawling. C3 is a more than a bit big but ORD takes their crew cab all over so I'll just have to see how nimble a big truck can be. I obviously am running the triple stick so I can run front wheel drive only, add cutting brakes to that for the rear and it should turn pretty good. I based a lot of the design on my Tundra but wanted something a bit more hardcore with bigger tires, shorter wheelbase and more clearance for some of the trails I want to connect on expedition trips. Tundra has a 145" wheelbase and might be a bit wider. Both have/will have bypass shocks that are the only way to go when the going gets fast! I've had heims, they are good but just wanted to try something that might be quieter and more factory riide like. If it fails it will be back to the heims. As for the critics, you might be right or wrong (I have my concerns as well), we'll know after its running and I beat the $hit out of it. If it breaks, I'll make something different. What isn't in the build thread is all the additional bracing I put on the passenger side steering mount because I know that it will see a ton of stress. This is unlike anything I have seen anyone else do so there isn't much to go on except me and my experience as an engineer and fabricator, not so much the welder though. Thanks for all the comments good and bad, that's how stuff gets better.
 
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