Popping my top

[Jsweezy]

Recommended U-Bolt Torque, Suspension Replacement Parts

Not sure exactly what your bolts are but this should help.

[boywonder]

Thanks! that's exactly the info that I need.

[Pntyrmvr]

Axle wrap is increased by the added leverage the blocks give the axle. The axle centreline moves further away from the spring and allows a greater change in ujoint angle.

This will manifest itself in a marked change in vibration while the driveline is heavily loaded. The angle is set perfectly in a static situation in a shop, but when under the gun the axle turns upwards thereby changing the angle. The blocks magnify this effect.

I plan on adding a 1 degree downward tilt to my rear axle when I shim it to allow for the upward tendency. Much reading on this subject suggests 1-1.5 degrees of upward windup is normal. With blocks who knows. New custom springs would fix this although I would still check the angle.

Some driveline shops will tune the shims based on repeated road tests to determine the exact shim degrees.

My Advanced conversion is from 1985. Doesn't look like they changed much.

U bolts are cheap. I'd replace them.


"Talk is cheap. Whiskey costs money."

[Flux]

Yesterday I had no idea what axle wrap is.

I learn something every day around here.

[Pntyrmvr]

Essentially as the axle shaft turns in one direction the axle housing wants to spin in the opposite direction. That spin also move the u joint.

High school physics. For every action there is an equal and opposite reaction.


"Talk is cheap. Whiskey costs money."

[Flux]

Yowza:

https://www.youtube.com/watch?v=54_6GaYJvWI

You can really see the differential and drive shaft moving up and those springs flexing with it. Seems to me that offroading and heavy travel would cause some wrap too as your drive shaft is a fixed length, that differential is gonna have to rotate a bit.

EDIT: I know know what a slip yoke is too thanks to shenrie's post below.

[shenrie]

^^^ most drivelines have a slip yoke. that guys tranny is all over the place too. and that's the shortest driveline ive ever seen, lol.

[boywonder]

......axle wrap is worse with tall lift blocks since the blocks act as a nice long lever arm on the springs......

[Flux]

That new Spring setup you got looks much stiffer than your old set.

Sorry to hijack your thread, I have all these.....questions!!

[Jsweezy]

Originally Posted by Pntyrmvr

My Advanced conversion is from 1985. Doesn't look like they changed much.

Maybe that's why my Advanced came with a 1987 Dana 44, if it ain't broke, don't fix it!