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.