what is the reference between pinon angel and caster as in degree ?

[dons68sport]

what the reference between pinon angel verse caster having bad steering problem like i am chasing the the wheel like scary bad
So here is what i have for a set up factory pitman arm drop bracket 2.5 lift 68 frame 77 d44 everything else is stock

 

[dons68sport]

there must be some reference between the 2 oh 7deg c bushings

 

[LUBr LuvR]

Pics of front end with dropped pitman arm. Has since been changed to stock per vendor recommendation.

Will post current pics later

 

[jamesroney]

what the reference between pinon angel verse caster having bad steering problem like i am chasing the the wheel like scary bad
So here is what i have for a set up factory pitman arm drop bracket 2.5 lift 68 frame 77 d44 everything else is stock

Pinion angle vs caster is shown in the pic. A Bronco is supposed to have perfectly horizontal radius arms. When it does, the caster sits at 4 degrees. and the pinion sits at 8 degrees. Bronco's with heavy duty springs, sit closer to 3 degrees of caster at 9 degrees pinion inclination. Once you lift them, the arms start to drop and the caster heads towards zero.

 

[Brush Hog]

I have 2.5 inch WH lift. Started with stock pitman arm and no track bar drop bracket. Steering wasn’t what I wanted it to be. After reading all the info on this forum I went to drop pitman arm and drop track bar and things improved. Your angles look pretty steep already so stock pitman arm is likely to make things worse. But every bronco is different. Just my $.02.

 

[Oldtimer]

My 77 D44 had a measured delta of 11.5° (driver) and 11.7° (pass) between pinion and inner Cs, before cut 'n' turn.
Jame's drawing shows a delta of 12°.

 

[Steve83]

The difference between them is set before the axle tubes are welded into the center casting. To change that difference, you'd have to cut the welds & rotate them.

The difference between adjusting the caster & adjusting the pinion is that caster will make the truck steer on pavement properly. Setting the pinion angle will reduce driveshaft vibration when in 4H at high speeds (like in sand, hard desert, prerunning, snowy highways...). Since very few people care about 4H at highway speeds, most ignore it & just set proper caster without cutting those welds.

(click this text)

 

[jamesroney]

My 77 D44 had a measured delta of 11.5° (driver) and 11.7° (pass) between pinion and inner Cs, before cut 'n' turn.
Jame's drawing shows a delta of 12°.

Did you confirm that the pinion centerline was orthogonal to the machined face of the cover? I always thought it was. but never knew 100%. Usually Spicer is pretty good at that, but it's not guaranteed.

That sketch was written on my garage wall over 20 years ago.

How is that cut and turn working out for you now that you've got that fancy new steering box? Still happy?

 

[Oldtimer]

I always assumed (risky) they were.
From a manufacturing perspective, life would not be pleasant if the pinion bore was not orthogonal to the machined face for the cover.
I did not measure pinion bearing bore angle to machined face.
I did measure angle of pinion end yolk cups for the driveshaft u-joint caps. It was parallel to machined face for cover, but not a lot of confidence in comparing the 3" span for u-joint to face that is over 1 foot away.

Love the cut and turn improved caster with rebuilt 4 turn box.
Bronco tracks great and returns to center when I let go of steering wheel.