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Build Thread - 1978 F150 1-tons and 40s

The angle isn’t to blame. Mine are 8* and there’s zero issue.

Did you ever crosstie or triangulate the panhard frame point? You said your steering gear mounting was cracked in the past, maybe there’s more cracks? DW is more likely to be side to side oscillation of weak/insufficient lateral control of the axle in relation to the frame. Differences in lengths or offsets will become noticeable. The result is the axle or drag link overcoming the torsion bar while you are holding the steering wheel stationary. And everything continues to compound. This is why I’m anti bushing when it comes to panhard bars.
 
WiscoF100 said:
The angle isn’t to blame. Mine are 8* and there’s zero issue.

Did you ever crosstie or triangulate the panhard frame point? You said your steering gear mounting was cracked in the past, maybe there’s more cracks? DW is more likely to be side to side oscillation of weak/insufficient lateral control of the axle in relation to the frame. Differences in lengths or offsets will become noticeable. The result is the axle or drag link overcoming the torsion bar while you are holding the steering wheel stationary. And everything continues to compound. This is why I’m anti bushing when it comes to panhard bars.
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I recorded the linkages yesterday while running the steering wheel back and forth and it looks like not only were the jam nuts on both links loose but the track bar might be adjusted a bit short. The frame mount hasn't been triangulated yet but it's pretty solid and the the frame under my steering box plate was extensively welded up; not seeing any movement at the steering box. Just looks like the track bar itself moved back and forth

Here's a video: steering test

If I can get under there today I'm going to adjust the links and tack the jam nuts.
 
rattle_snake said:
both rod ends on the drag link are sloppy. replace.

That amount of slop can cause DW.
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Thanks I honestly wasn’t too sure. What do you think of the track bar movement in the video? Just too short?

edit: Re-reading this I think you meant the rod ends on the track bar right?
 
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Had trouble loading video earlier. Yes, the panhard heims definitely have play. Hard to tell if camera perspective or not but it appears the pitman and drag link BJ aren’t corresponding either. Same goes for pass knuckle assembly etc.

Were the heims new for the project? What size? Bolt diameter? Room to upgrade? Verify the mounting bolts were tight and or haven’t wallowed out.

Before tack welding the jam nuts, I’d re-torque and test again. It’s just unnecessary in my experience as I’ve never had one come loose on me.
 
WiscoF100 said:
Had trouble loading video earlier. Yes, the panhard heims definitely have play. Hard to tell if camera perspective or not but it appears the pitman and drag link BJ aren’t corresponding either. Same goes for pass knuckle assembly etc.

Were the heims new for the project? What size? Bolt diameter? Room to upgrade? Verify the mounting bolts were tight and or haven’t wallowed out.

Before tack welding the jam nuts, I’d re-torque and test again. It’s just unnecessary in my experience as I’ve never had one come loose on me.
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Heims were brand new for the project:

Heims - 7/8"-7/8" 3-Piece Precision Heat Treated Chromoly Teflon Lined Right Hand Heim

Misalignment spacers - 7/8 to 9/16 High Misalignment Spacer Zinc Plated Steel 2 Mounting Width

There is definitely play between the bolt and the misalignment spacers on both ends but I haven't done this enough to know if that's acceptable or not (I'm thinking it's not). First 10 seconds of this video shows it: panhard heim play

Will probably replace with the TMR heims and spacers: 7/8” Rod End (Heim Joint) Package with Hex Tube Adapter

Both axle and frame bracket barely have a few miles on them and are in good shape.

As for the drag-link the TRE on the pitman arm is brand new so maybe I can just tighten that up, but the passenger side is what came with the axle so I'll go ahead and replace that.
 
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Ok 7/8x 7/8 is good. The slop must be in the misalignment and bolt.

Unpopular opinion but what about dumping the 9/16 and going 7/8? Or a 7x8 x 3/4 heim with 3/4 bolt? I personally wouldn’t opt for a reduction. Frame side is def possible. If the angles are correct, then drill out the axle side too. There no need for universal positioning once the geometry is correct.

Also a preference of mine, if not a reamer, undersize the hole, then drill to final size using a step drill. You’ll end up with a much higher tolerance bore than a standard twist drill.
 
WiscoF100 said:
Ok 7/8x 7/8 is good. The slop must be in the misalignment and bolt.

Unpopular opinion but what about dumping the 9/16 and going 7/8? Or a 7x8 x 3/4 heim with 3/4 bolt? I personally wouldn’t opt for a reduction. Frame side is def possible. If the angles are correct, then drill out the axle side too. There no need for universal positioning once the geometry is correct.

Also a preference of mine, if not a reamer, undersize the hole, then drill to final size using a step drill. You’ll end up with a much higher tolerance bore than a standard twist drill.
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I'm a bum with limited time for a while so I went the lazy route and ordered better heims/bolts/misalignment spacers from TMR.

Also, I hate drilling holes/reaming under the truck. My Milwuakee magnum drill has kicked my ass a number of times doing things like reaming out the trackbar mount on the original HP D44 to install a trackbar stud :homer:
 
Still waiting on new rod ends, misalignment spacers, and bolts... they should be here on Monday or Tuesday. I pulled the panhard out and painted it, the brackets, etc.

Got the Bilstein 5100s for the rear, painted the mounts on the axle, will install those tomorrow.

When I built my draglink I used a kit that uses the existing draglink end on the axle side, and a GM Moog draglink on the pitman arm side. It comes with tube inserts designed to be used with 1 3/4" DOM. I noticed that the knuckle side was nice and tight but the pitman arm side was pretty loose. Going to order just the tube inserts to build a new draglink and hopefully tighten that up. Its possible I warped the threads or something.

Something else I've noticed/been fighting with is the rear brakes. When I got the rear axle the backing plates were wrecked to shit from being shipped. I decided to just trim them back as much as possible and deal with it later. Took a look at it again today to see if the parking brake lever was stuck and it's not, the only thing I can think of is the backing plate isn't letting the shoes rest where they belong because the sound and drag I get from it is intermittent.

I need to get this truck smogged before I move so I just pulled the rear shoes out of the one side giving me problems. Will have to pull it all apart and install new back plates I guess. This is all weird because the parking brake isn't even hooked up at this point.

I'm so close to being able to drive this thing regularly (I'm going to have to for awhile once I move into the new place) but all this little shit is getting in the way. I'll feel a lot better once I know the death wobble situation is resolved.
 
There were some weather delays getting the new misalignment spacers, FK rod ends, and bolts from TMR but they arrived today. They are WAY tighter than the Barnes4wd misalignment spacer. Looks like WFO makes their own stainless steel misalignments in house as well. I'll pay more attention in the future.

Also, comparing the FK rod end to the Barnes rod end: they look VERY similar, the only obvious difference between the two is one says FK and Made in USA on it. But when I went to install my panhard I found that the frame side rod end didn't fit because it's just a bit beefier. I'll have to clearance my mount to accomodate the beef but no big deal.

Next up: Painted my draglink and waiting for it to dry, need to install rear shocks, clearance the panhard mount on the frame side, install the panhard and I'll be ready to give it another try.
 
Well I'm stumped.

Installed the rear shocks then painted the panhard and draglink, got them installed with the new misalignments, FK rod ends, and new bolts/etc from TMR. Jam nuts nice and tight and marked them to see if they loosen up at all. Took a little before video and everything looked way better than with the Barnes stuff.

Took it for a test drive and here's what happened:

- This can be completely in my head but going about 25ish mph it feels like the front-end is going over a bunch of little bumps in the road. Maybe a "micro-wobble"?

- I got up to 40-45 and it felt fine.

- Going about 30ish I hit a bump in the road and the death wobble came on. I coasted for maybe 20-25 feet before hitting the brakes to slow down which is when it finally stopped.

- All the bolts/nuts stayed put.

- Took a video of it parked, engine off, and turning the wheel back and forth hard.. panhard and draglink look good to me.


I really thought a 44.5" panhard and 50" draglink should be fine.. as in, close enough. Here's a video of the current state of things.. is that tiny bit of play in the panhard acceptable? Not really sure what to do about that if not:
photos.app.goo.gl

New video by Charles Howard

photos.app.goo.gl photos.app.goo.gl


Before I get too into the weeds on this I'll take it in to get an alignment. Who knows if I got the caster right (I did my best to set it to 5 degrees), check if the wheelbase is even front to back, I didn't mess with toe.
 
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The length of the tracbar isnt your problem.

Why is there so much slop at the upper heim joint? Bolt doesnt fit the heim?
 
reptillikus said:
The length of the tracbar isnt your problem.

Why is there so much slop at the upper heim joint? Bolt doesnt fit the heim?
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Heim, bolt, and misalignment are all brand new from TMR and felt/looked perfect in hand. Will have to take a closer look tomorrow.
 
Going to take this thing in for an alignment this week but something that I haven't seen talked about much is draglink and panhard separation/angle when looking from the side like this:

IMG_6264.jpg
IMG_6272.jpg

About 11" apart on driver's side, and 5" on the passenger side. It seems to me that the effective length of the draglink in comparison to the panhard is reduced exponentially as the axle droops. I noticed this when I was slapping this thing together but figured it was a problem for later if at all.. I'm really not sure, curious to hear everyone's thoughts/insights.

If this is the issue then it looks like I'll need to swap to a steering box (superduty probably) on the inside of the frame rail so I can move it back enough to pull the draglink backwards.

IMG_6273.jpg

IMG_6272.jpg

This picture is from Battle Born Brakes who makes bolt-in Superduty axle swaps for 67-79 trucks. This link/picture is for an F250 with leaf-suspension but it shows a Superduty steering box: F250 2wd to 2005+ Super Duty front axle, steering and suspension kit SDAF25 | Battle Born Brakes

Screenshot 2024-10-06 at 12.56.36.png

This is the F100/F150/Bronco kit showing how much separation there is in his kit with the draglink/panhard but no idea how well these things go down the road:
Screenshot 2024-10-06 at 12.57.58.png


Anyway, still taking this thing to get an alignment to see if that helps at all. Need to pull the panhard upper and inspect the heim/misalignment/etc. I really don't know what's expected/tolerated as far as play in those things. I'll be surprised if that's my problem as I thought I was buying good stuff.
 
I think what you have is bumpsteer. Changing boxes to alter side separation won't do anything.

No need to take it to an alignment shop. Just set toe to 0 or 1/16 in and you are good. 5* caster is good.

Have you tried the other two hole locations in the axle side track bar mount??

What happens when you hit a BIG bump at 40-50 MPH?
 
rattle_snake said:
I think what you have is bumpsteer. Changing boxes to alter side separation won't do anything.

No need to take it to an alignment shop. Just set toe to 0 or 1/16 in and you are good. 5* caster is good.

Have you tried the other two hole locations in the axle side track bar mount??

What happens when you hit a BIG bump at 40-50 MPH?
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I have a bit of doubt about how I measured caster. When doing it on an 05+ D60 I read that you can use this flat area between the coil bucket and upper balljoint area. I did my best setting it at 5* and chances are it is right but I figure it can't hurt to get an alignment done and just know for certain. I did check my wheel base and it seems to be even on both sides. I'll look at checking/setting the toe in.

IMG_4592.jpg

I'll give the other track bar mounting locations a shot just to see what happens.

This death wobble is super jarring (to what I've experience in other people's rigs in the past) so I'm not going to pretend like I wouldn't be afraid to hit a big bump at that speed but I guess there's not a whole lot that can go wrong, so I'll work up the balls to do it :laughing: . With that said, what would it tell us if I hit a big bump and everything is fine?

Also, there's just ever-so-little play in the upper track bar heim/misalignment/bolt in hand. It's WAY less than the old Barnes stuff. I'm really not sure what to expect there though, should there be zero perceivable play in a quality joint like that? Watching my most recent videos with the new hardware I do see the upper mount movement. I'm curious what other's experience is in that regard.
 
BJ flat is good to measure caster.

If you have essentially minimal bump steer, it should not DW. If you can send it over a big bump and you stay in your lane without moving the steering wheel, all is good.

Small bumps in the road cause axle to move slightly vertical, and bump steer turns this into steering left and right with steering wheel held tight. They build on one another, aka DW.

There will always be some amount of play, but new joints should be minimal.
 
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