1978 F-fun hundred 3/4 tons and 37s

The material I have is pretty clean but the I.D. is exactly the O.D. of the thin wall. Couldn’t tell ya how many hairs I removed, I just made passes until it was snug and then pressed it in.

.120 wall has .010” of clearance inside whereas the .250 is .000”
 
Rushed it together for a quick spin. Installed the front plastic wheel tubs before I left. Surprised they work with fender exit headers!

Carelessly I set the toe-in at about 1/16”. It’s okayish. Still not in love with things. The bump steer is noticeable. Not world ending but it sucks to go from none to something. New pitman arm in the works.
IMG_0677.jpeg
IMG_0671.jpeg
IMG_0681.jpeg
IMG_0682.jpeg


Temporary fix was to flip the tie rod. I’ll get all that old T link stuff chopped off tonight.
IMG_0680.jpeg
 
rattle_snake that would make it worse. The DL came out flatter. 2.1* less than the panhard. Also if I moved it over the top it would basically kill all uptravel. The angle now has me bummed/concerned about clearances. I’m going to harvest the splines from the racecar pitman to make a new plate style.

Also I’m shopping coil springs. Need to drop the front 1”-1.5” to level this thing. That would add caster and reduce link angles.

This phase is actually kinda fun. It’s already banged up so now I just work on it instead of being afraid of nicking the paint off the parts.
 
Steering chit chat continued

Took a break to roll some ideas around. Trying to plan this out where I can test concepts/work through the unpleasant steering but not back myself into a corner I can’t return from or continue to waste material/parts.

What I have settled on is tie rod under like OE. It’s a compromise that also yields benefits like not crashing into the panhard bracket.
IMG_0704.jpeg

Keeping the drag link in double shear and lowering it,
A) I don’t have to cut it up and extend it yet again
B) it brings the angles within .7* of each other. 1.7* improvement
IMG_0706.jpeg

Unfortunately it doesn’t leave much room between the tab and tie rod for a nut. I’ll weld a low profile insert for the time being. That new wing is set at a distance to allow me to stack the links again if I need to relocate the tie rod. It would require chopping off what’s left of the high steer arm so the drag link doesn’t bind. Also extending the drag link once again. That’s kinda last resort plan. It would also 100% require a new pitman arm to align the angles preventing bump steer.
IMG_0707.jpeg

Clearance is clearance
IMG_0708.jpeg

It may look like the travel is used up but it still has more travel than I’ve built this thing for left in it. New coils are on the way from skyjacker. Lowering the nose will benefit everything all around.
IMG_0709.jpeg

Ready to harvest the splines as a back up plan. I bought a sheet of 3/16” today to fab a new arm. I’ll weld that washer as a pilot for the holesaw. Cup saw for the snow Mexicans
IMG_0710.jpeg
 
Hard to tell without seeing in person how it all packages. I reworked my track bar mounts many times to get max uptravel with minimal angle. Everything ground/cut/turd polished to just fit. Diff, engine cross member, frame rails, bumps, straps. Hopefully your setup works, and you can test it out without completely committing.
 
Here’s final welding full bump pictures from July.

This is it. 6+ uptravel. 5” lift over stock. Uncut frame rails. I’m fine with my angles. You just can’t package anything “upward” on the axle. There’d be no uptravel left. It was built at full bump, articulated, left, right. The tie rod crashes into the panhard left and right- that’s with the reverse Ackerman, moving the pivots forward and using 1” offset heims. You can tell by the spring bucket that a 23” coil will never compress that far. Gotta suck it up and focus on this truck being a safe daily driver not what’s trending in the crawler world.

If it were trail duty only, I wouldn’t have touched a thing. It’s fun on dirt
IMG_8991.jpeg
IMG_8993.jpeg
IMG_8996.jpeg
IMG_8989.jpeg
IMG_8988.jpeg
IMG_8986.jpeg
IMG_8984.jpeg
IMG_8983.jpeg
 
Last edited:
Looks good. 5" of up is great. Is that before or after lowering with shorter springs? Do you need bump stops to prevent tire into fender?

Interesting to see how it all fits. different set of puzzles to solve.
 
No, I’m getting away from that. I’ll leave the tabs there just because. The tie rod is still above the bottom of the axle tube. Honestly I won’t be smashing this thing into rocks anyways.
 
No, I’m getting away from that. I’ll leave the tabs there just because. The tie rod is still above the bottom of the axle tube. Honestly I won’t be smashing this thing into rocks anyways.
Oh, last pics are old ones then, got it
 
Looks good. 5" of up is great. Is that before or after lowering with shorter springs? Do you need bump stops to prevent tire into fender?

Interesting to see how it all fits. different set of puzzles to solve.
I’ll need to plan bumps eventually. Rear much easier than front. The reality is with these massive coils and radius arms it’ll never achieve the travel numbers it’s built with.

Shorter coils may finally get the tire into the front fender dogleg. Mall crawlin everything clears and I’ve only used 3” of shock uptravel so far indicated by zip ties while clipping along dirt roads.

Had to work last night. Posted when getting home. Now awake to get back after it.
 
I wanted to post an update while I was in Canada for Christmas but the job was incomplete so I didn’t.

More successful-ish test drive tonight
IMG_0808.jpeg

This is where progress stopped before going up there a day earlier than planned.
IMG_0747.jpeg
IMG_0779.jpeg
IMG_0780.jpeg
IMG_0781.jpeg

Not my idea, credit goes to some dude on FTE. ‘96 F Series J hook arms that I’ll cut down. F those stupid ass bayonet wiper blades. Wish I would thought of this before buying 2 new bayonet style arms.
IMG_0778.jpeg

Ready for the test drive
IMG_0806.jpeg

Hard to tell but I used retired safety washer style high misalignment spacers from the race car. Eventually I’ll “triple” shear the tie rod for safety. I really hate the idea of the nut alone keeping the steering together. Don’t like single shear at all.
IMG_0807.jpeg

Found some new wheels to try lol
IMG_0811.jpeg

IMG_0809.jpeg


Ackerman was the trick. Wayyyyyyyyy more predictable off center and corner entry. 70+ feels safe now.

It’s still lacking caster. Return to center is the only thing missing now. Turns out I only have 2*. Gotta buy 7* wedge bushings which will net 5* caster.
 
Last edited:
Nice build.

Working out the bugs and tuning, especially when it involves cutting up existing work, can be frustrating. Glad to see it explained and shown.
 
Thank you

It has been frustrating and humbling. Building for street manners was an eye opener. It’s been fun though, experiencing the engineering and results in real time.

No pictures of the coil swap. It was a bust. Much lower than anticipated. What I’m thinking now is stepping down to 35s with those coils and removing the leaf spring blocks.
 
I wanted to post an update while I was in Canada for Christmas but the job was incomplete so I didn’t.

More successful-ish test drive tonight
IMG_0808.jpeg

This is where progress stopped before going up there a day earlier than planned.
IMG_0747.jpeg
IMG_0779.jpeg
IMG_0780.jpeg
IMG_0781.jpeg

Not my idea, credit goes to some dude on FTE. ‘96 F Series J hook arms that I’ll cut down. F those stupid ass bayonet wiper blades. Wish I would thought of this before buying 2 new bayonet style arms.
IMG_0778.jpeg

Ready for the test drive
IMG_0806.jpeg

Hard to tell but I used retired safety washer style high misalignment spacers from the race car. Eventually I’ll “triple” shear the tie rod for safety. I really hate the idea of the nut alone keeping the steering together. Don’t like single shear at all.
IMG_0807.jpeg

Found some new wheels to try lol
IMG_0811.jpeg

IMG_0809.jpeg


Ackerman was the trick. Wayyyyyyyyy more predictable off center and corner entry. 70+ feels safe now.

It’s still lacking caster. Return to center is the only thing missing now. Turns out I only have 2*. Gotta buy 7* wedge bushings which will net 5* caster.
How are you measuring your caster?
 
This wiper arm mod went pretty easy

First I drilled the rivet with an 1/8” bit
IMG_0911.jpeg

With the rivet gone, I held the arm in the vise to peel open the folded sheet metal. Then simply slide the arm to slack the spring and remove. Real easy
IMG_0909.jpeg
IMG_0910.jpeg

Press the bend for the spring flat to slide arm away from sheet metal body
IMG_0912.jpeg

Messy mock-up to confirm 3.25” as per the info on FTE was correct. It comes out to 21.5”. Tape measure laid against the glass says it’ll work. I’ll confirm once the paint dries. :homer:
IMG_0914.jpeg

Little bend for the spring
IMG_0915.jpeg

I used these side cutters or whatever they’re called to open the pinch seam to lay the arm in place. Used a 6-32 stainless screw instead of a rivet. Made a pass with a tap since 1/8” is slightly undersized. Used the press to pinch the body back over the arm.
IMG_0917.jpeg

IMG_0916.jpeg

Had to rebuild my entire water system with pex. The water in our town kills copper.
IMG_0898.jpeg

Block heater trying to melt the snow off the truck for me
IMG_0892.jpeg
 
Lowered the rig today and drove it.

Caster is 4.6* without changing wedge bushings.

Caster was the missing piece. Still a little wander but immediately noticed the difference before the end of the block. So much nicer at speed.

35x12.50r17 tires arrive Wednesday
IMG_0982.jpeg
IMG_0983.jpeg
IMG_0981.jpeg
IMG_0980.jpeg
 
Skyjacker 174VS 4” lift. Gave dentside_dave the sale.

Removed the rear blocks. Truck fits under the garage door now. Excited about that. Before, I had to run a 2” cargo strap under the front axle to suck it down and it still brushed the door gasket. Links are down to 4.8*

Truck rides a little nicer, too
IMG_0992.jpeg

IMG_0993.jpeg


-20* startup. Block heater plugged in of course
IMG_0988.jpeg
IMG_0989.jpeg
 
Last edited:
Top Back Refresh