D44 inner C cut & turn

[nvrstuk]

2deg pinion climb at highway speeds on the flats w/3.5:1 ??
Springs make all the difference for sure.

I think this would be a good GoPro camera project-unless someone here can link to an example.

I always ran rear antiwrap bars-always. One of the reasons I went thru so many leaf springs and rear shackles I'm sure. They sure help that leaf spring turn into an "S" when you accelerate!

 

[Broncobowsher]

I remember getting a set of soft leafs. Parked it nose up on a dirt mound. Nothing super crazy. Looked underneath and saw the pinion climbed a bunch, maybe 10°?
Started building torque arms. I bent and broke so many of them. That was just driving around town. Got one to stay, went wheeling and ripped the bracket off the axle (peeled open the axle tube). Finally built a torque arm out of a radius arm with the front on a tractor 3-point heim and leaf spring shackle so it wouldn't bind fore/aft. That was the only way I could control the soft leaf springs and keep control of the pinion angle without hurting travel/articulation. Always had a rock stable pinion angle with the torque arm in place.

To say there is only 2° pinion rise at highway speeds, I'm thinking you still have a stiffer spring pack. Not rock hard, but there are softer springs that will wind up more.

 

[jamesroney]

I remember getting a set of soft leafs. Parked it nose up on a dirt mound. Nothing super crazy. Looked underneath and saw the pinion climbed a bunch, maybe 10°?
Started building torque arms. I bent and broke so many of them. That was just driving around town. Got one to stay, went wheeling and ripped the bracket off the axle (peeled open the axle tube). Finally built a torque arm out of a radius arm with the front on a tractor 3-point heim and leaf spring shackle so it wouldn't bind fore/aft. That was the only way I could control the soft leaf springs and keep control of the pinion angle without hurting travel/articulation. Always had a rock stable pinion angle with the torque arm in place.

To say there is only 2° pinion rise at highway speeds, I'm thinking you still have a stiffer spring pack. Not rock hard, but there are softer springs that will wind up more.

Where is the protractor and go-pro guy? My 170 cubic inch six will push my Bronco to about 60 on a flat at part throttle. But I have no clue how much torque is being produced. But at WOT and at 2400 rpm, when it was brand new, on premium fuel...it could output 105 HP, and 156 lb-ft at the flywheel.

I'm not getting paid enough to do the math, but it would be something like 30 HP required to push a 3500 lb brick at 65 mph on a flat, overcoming both wind, and rolling resistance. Turning that number into torque at the wheel gets you about 114 lb-ft, and divide by 4 for the gear ratio...and you end up with something like 30 lb-ft of torque at the pinion. So the answer is somewhere between 30 lb-ft, and 156 lb-ft. Average tightening spec for a 3/8-24 hex nut on a 1350 u-joint nut is about 30 lb-ft. So how much does the pinion rise when I tighten the u-joint? I can measure that!

I need the protractor and Go-pro guy...

 

[nvrstuk]

I agree that on a soft dirt mound or anything else with load (tire against a curb) that the pinion rotates- this is fact since soft leaves came out in the late '90's. (well before this but for us this is when we started grenading parts because of soft springs).

I remember somebody on our old BroncoFix site posted a video and convinced us some 25yrs ago - most of us were unaware of the amount of pinion movement possible at that time. At least everyone I wheeled with was as we were all talking about the video.

I couldn't afford to buy new pinions or ujoints repeatedly so I made an anti-wrap bar back prior to '97 similar to what Wild Horses sells now. Ate bushings to no end because it was used everyday. Designed a modified 3 pt mount that Lee N. made prior to his Barbie build and it lasted almost 15 yrs but I ate spring packs and spring hangars regularly and this was prior to huge HP #'s but I ran doublers and ZF's and torque multiplication was phenomal, but Lee's modified design with 3 mounts spread out (one on top and the two others on the tube housing could take the load much better than a single mount on a 9" housing so metal wasn't torn away from factory welds in my case.

Anyway, still be impressive to see pinion rotatation when cruising at the suggested speed of 65 mph, not up a grade, not under acceleration or in low gear on a mound since we've all had buddy's destroy pinions, ujoints and driveshafts from not having a good anti-wrap bar to keep pinion rotation to an absolute minimum- so that's a given under load- just not a given under a slight 65 mph cruise example - - probably moves some tho!

 

[nvrstuk]

james- be kinda fun to try this but there are too many variables to get anywhere close I think.

You mentioned-
" I'm not getting paid enough to do the math, but it would be something like 30 HP required to push a 3500 lb brick at 65 mph on a flat, overcoming both wind, and rolling resistance. Turning that number into torque at the wheel gets you about 114 lb-ft, and divide by 4 for the gear ratio...and you end up with something like 30 lb-ft of torque at the pinion. So the answer is somewhere between 30 lb-ft, and 156 lb-ft. Average tightening spec for a 3/8-24 hex nut on a 1350 u-joint nut is about 30 lb-ft. So how much does the pinion rise when I tighten the u-joint? I can measure that. "

Many questions but this is the first- Where does the spring rate figure into the math?

 

[toddz69]

I remember getting a set of soft leafs. Parked it nose up on a dirt mound. Nothing super crazy. Looked underneath and saw the pinion climbed a bunch, maybe 10°?
Started building torque arms. I bent and broke so many of them. That was just driving around town. Got one to stay, went wheeling and ripped the bracket off the axle (peeled open the axle tube). Finally built a torque arm out of a radius arm with the front on a tractor 3-point heim and leaf spring shackle so it wouldn't bind fore/aft. That was the only way I could control the soft leaf springs and keep control of the pinion angle without hurting travel/articulation. Always had a rock stable pinion angle with the torque arm in place.

To say there is only 2° pinion rise at highway speeds, I'm thinking you still have a stiffer spring pack. Not rock hard, but there are softer springs that will wind up more.

Sounds like that could've been my old pair of Nationals that went to you at some point?

Todd Z.

 

[jamesroney]

james- be kinda fun to try this but there are too many variables to get anywhere close I think.

You mentioned-
" I'm not getting paid enough to do the math, but it would be something like 30 HP required to push a 3500 lb brick at 65 mph on a flat, overcoming both wind, and rolling resistance. Turning that number into torque at the wheel gets you about 114 lb-ft, and divide by 4 for the gear ratio...and you end up with something like 30 lb-ft of torque at the pinion. So the answer is somewhere between 30 lb-ft, and 156 lb-ft. Average tightening spec for a 3/8-24 hex nut on a 1350 u-joint nut is about 30 lb-ft. So how much does the pinion rise when I tighten the u-joint? I can measure that. "

Many questions but this is the first- Where does the spring rate figure into the math?

Oh, I wasn't anywhere close to developing a relationship between driveshaft torque and pinion rise. I was first trying to figure out how much torque the pinion sees at cruise. Then I figured I would apply that torque to the pinion nut and see how it reacted.

That's where spring rate, geometry, bending moment, and load would come into play. But I still like your Go-Pro idea best.

 

[Broncobowsher]

Sounds like that could've been my old pair of Nationals that went to you at some point?

Todd Z.

Sagged out 10-leafs I got from Randy about 01 or 02. Didn't help that I also had a set of lift blocks under them as well.

 

[gtme1996]

Been sidelined by some medical issues but I finally started working on my axle. I’ve gotten on side ground down to where I’d think the crack would be but I’m not seeing it. Any thoughts? Do I need to grind into the C more? I really don’t want to screw this up!

 

[lars]

Been sidelined by some medical issues but I finally started working on my axle. I’ve gotten on side ground down to where I’d think the crack would be but I’m not seeing it. Any thoughts? Do I need to grind into the C more? I really don’t want to screw this up!

My memory is kinda dim after all these years and I've only done one (mine) but yeah, more over into the C and less in to the tube- no deeper than you've already gone. Maybe James will chime in, his experience is broader and more recent.

 

[nvrstuk]

Agreed, less tube thinning!

 

[gtme1996]

Agreed, less tube thinning!

Thanks for the input! I kinda wish I hadn’t made that last pass around but I thought it just might show me something.

 

[Apogee]

I semi-recently did this on a '76 F150 HPD44, and I had to cut into the C a bit more, though I was using an air arc to do it for speed reasons. I heated it up with a torch and expanded the C's on the tube and the crack appeared pretty readily at that point...still put up a fight coming off, but at least I could see a crack all the way around. I put it in the press and coaxed it off with about 25 tons of force after building a lift kit for the H-frame press, as the housing was too long...but an EB width might have worked. Once off, I cleaned everything up and things certainly went together a lot easier...I put a stop on the tube, heated up the C, dropped it on and then clocked it where I wanted it and it shrank into place. A few heavy gorilla tacks and they're where I think I want them, but I'm rotating the wedges and the C's, so I was able to set my pinion angle and caster separately. It's mocked up under the rig now and just waiting on the steering and track bar before I do the full weldout, but I set it with 6° caster at ride height with CAGE long arms and 3" lift springs, which goes to 0° at full stuff and 12° at full droop.

 

[gtme1996]

Well, a lot has happened since my last post but none of it has involved my axle housing. A couple of medical incidents and unexpected home repairs plus life in general have kept me from working on it and unfortunately, I don't see that changing anytime soon. So...is there anybody out there who might be able to finish this thing for me? I'm near Savannah, GA so anywhere in eastern GA or western SC and maybe even NC near I-95 could be doable. Worst case, I might bite the bullet and ship it somewhere. Thanks in advance.

 

[Apogee]

I'm sorry about the unforeseen medical stuff, but hope you're feeling better. Hopefully someone local to you can help you out, as I think shipping to the West Coast would be a cost prohibitive.

 

[ntsqd]

Years ago I suggested a design for a tool to make measuring the caster of a bare housing. The original suggestion consisted of two cone shaped pieces of metal that matched the diameters and the taper of the lower ball-joint hole in the 'C', and another to match the taper & diameters for the upper ball-joint. Thru them is a reamed hole for translational slip-fit on a piece of drill rod or other precision diameter round bar. With the tool inserted a simple angle finder pressed against the side of the bar would measure the before and the after angles.
My design suggestion since evolved to using a pair of discs rather than the cones. The diameter of these discs need to be such that one edge of each is roughly centered in each taper. I further evolved it in suggesting that the lower disc not be a translational slip-fit like the hole in the upper disc, that it instead be a light press-fit. With a spacer (or by making the upper disc fairly long) and a shaft collar from McMaster the tool will hold itself in place.

With a Wrap-Trap type of anti-wrap linkage the forward half of the leaf springs will be in compression. Not quite true of the ladder bar w/ shackle design.* I would expect the compressive strength of the main leaf to be a large part of predicting how much pinion angle delta there is under load. No doubt the other leaves will be a factor, but the main leaf is the only one constrained at both ends. I don't think Euler's formula will handle a curved rectangular "column" very easily........ the math there might be rather ugly.

*I'll suggest that those with a ladder bar design pull the bolt at the front end of the ladder bar, and then conduct some experiments in looking at how far and in what direction that end of the ladder bar moves relative to the shackle as the suspension cycles. I did this with the Bronc-up by mocking up a "ladder bar" that I bolted to the pinion carrier. My results are why I've since been saying since then that if a Wrap-Trap isn't enough axle control that you need to go to a 4 link. The ladder bar, as typically implemented, isn't a good design. Unless you like torturing leaf springs and tearing stuff up. Then it's an excellent design. Put it this way, w/o a ladder bar the pinion angle relative to the ground isn't fixed, but it doesn't change nearly as much as it is commonly thought to. Certainly FAR less than a ladder bar forces it to change. IF you're determined to run a ladder bar with leaf springs you would be well advised to build housing rotators, ala some drag racer suspensions or how one particular "Early Bronco" desert racer was built, instead of rigidly clamping the housing to the leaf springs.

 

[nvrstuk]

You put this out there "well", TS!

I think your idea is great & would have paid to rent it from ya when doing mine. Slick idea for sure.

I went thru all this as others have over the decades & I fought it & fought it..."it" being as you said- "torturing leaf springs and tearing stuff up" as you said above.

I built a single antiwrap bar that was attached (in three places) on top of the center of the rear housing and on each side of the drop in carrier to spread the load and I did cycle my suspension full travel b4 building the frt swing shackle and knew I'd have to deal with pinion angle thru 14" of straight droop/rise. 4 link cured it all but I wasn't ready (for several reasons) to build it then.

4 link cured it all... Great explanation!

Pic shows frt shackle antiwrap disconnected & hanging.

 

[ntsqd]

I know that at least one of those tools has been made. I didn't make it and I've no idea if the builder still has it or who does.

How I would approach it being out of the truck would be to ask people with the same amount of lift to measure the angle of the inspection cover gasket surface while parked on level ground. A simple digital level could be zero'd on the ground so that any slight slope is taken out of the measurement. Shouldn't take too many responses to zero in on what is normal. Then set the housing up on some BIG V-blocks* duplicating that averaged angle, and clamp the housing down so that it can't move.
Next using something like the tool that I described above I would set the 'C's to the desired Caster angle and weld them into place.

*I bought a cheap set of these to work on Snowball's rear D60 housing. I *think* that I bought them off amazon.
[EDIT] I did get them from amazon, LINK.[/EDIT]
They're not high precision, but this work didn't need anything better than these. Found a pic of it set-up on the mill when I machined the housing for the speed sensor:

Why a Ford guy painted those housings Chevy Orange I'll never understand.

 

[Yeller]

Excellent description of all that!

Chevy Orange is what all the cool kids run on their axles, if they are clown cars and why mine are black, I’m not near cool enough for orange

 

[jamesroney]

Excellent description of all that!

Chevy Orange is what all the cool kids run on their axles, if they are clown cars and why mine are black, I’m not near cool enough for orange

I agree. The only other acceptable paint scheme is the random blue paint stripe indicating that you bought your axle from the truck section of the pick-n-pull.

Also important to write in indelible yellow paint stick on the cover a large "710" and "ON"

I'm not joking. Lots of rigs out here running the "710" rear axle.