Caster / pinion angle
#11
JK Jedi
I meant to say "a bit more peace of mind for when we run Holy Cross on the next trip!"
Last edited by resharp001; 08-18-2020 at 08:11 AM.
#12
Super Moderator
For the vibration check the new flange to ensure it is tight on the TC. Friend years ago had this issue on his 78 F150 when it was near new.
Last edited by Sixty4x4; 08-18-2020 at 06:19 AM.
#13
JK Enthusiast
Thread Starter
good point. When I had the drive shaft installed, it had the vibration(very slight). I went to Moab and the drive shaft actually became really loose. I guess the installer forgot to locktight the bolts. The shop in Moab didn't do anything to the flange as far as I know.
#14
JK Enthusiast
Thread Starter
Well, I just shortened my UCA's by 1 revolution and changed the angle by 1* (at the flat spot on the diff). Test drove the jeep and the steering is better (less wander), but the rumble appears to be a little more noticable. Going to pull the DS at next opportunity.
#15
JK Enthusiast
Man my iPad hates this site anymore, multiple resets , slow loading, and very slow typing response.
Last edited by Seizer; 08-18-2020 at 04:54 PM.
#16
JK Enthusiast
The real question I guess is what driveshaft do you have now? That would determine what your pinion angle should ideally be, then you can play the caster game some more to find the mix of drive ability versus happy angles
Last edited by murdoc319; 08-18-2020 at 06:51 PM.
#17
JK Enthusiast
Thread Starter
i thought 3 degrees of caster was the sweet spot after a lift? The factory setup should have 4 degrees of caster built in when the pinion flange is at 90 degrees. Rotating the pinion up 1 degree leaves you with 3 degrees of caster. If you’re at more than 4 degrees, wouldn’t your pinion flange be less than 90, potentially causing a vibration?
The real question I guess is what driveshaft do you have now? That would determine what your pinion angle should ideally be, then you can play the caster game some more to find the mix of drive ability versus happy angles
The real question I guess is what driveshaft do you have now? That would determine what your pinion angle should ideally be, then you can play the caster game some more to find the mix of drive ability versus happy angles
Last edited by pcmasten; 08-18-2020 at 10:11 PM. Reason: additional info
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murdoc319 (08-19-2020)
#18
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i thought 3 degrees of caster was the sweet spot after a lift? The factory setup should have 4 degrees of caster built in when the pinion flange is at 90 degrees. Rotating the pinion up 1 degree leaves you with 3 degrees of caster. If you’re at more than 4 degrees, wouldn’t your pinion flange be less than 90, potentially causing a vibration?
Caster 7* = Pinion 1* dn
Caster 6* = Pinion 0*
Caster 5* = Pinion 1* up
Caster 4* = Pinion 2* up
Caster 3* = Pinion 3* up
This is am image from the Dynatrac PR44 FAQ that has been floating around for years now. Gives a decent illustration of how rotating the housing will affect caster and pinion angles.
#19
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Better to use posted numbers as starting points, not hard fact. The 'best' caster/pinion angles will depend on lift height, type of driveshaft joints, usage, etc.
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murdoc319 (08-19-2020)
#20
JK Enthusiast
You're on the right track, but there is a 6* separation between Caster and Pinion, not 4.
Caster 7* = Pinion 1* dn
Caster 6* = Pinion 0*
Caster 5* = Pinion 1* up
Caster 4* = Pinion 2* up
Caster 3* = Pinion 3* up
This is am image from the Dynatrac PR44 FAQ that has been floating around for years now. Gives a decent illustration of how rotating the housing will affect caster and pinion angles.
Caster 7* = Pinion 1* dn
Caster 6* = Pinion 0*
Caster 5* = Pinion 1* up
Caster 4* = Pinion 2* up
Caster 3* = Pinion 3* up
This is am image from the Dynatrac PR44 FAQ that has been floating around for years now. Gives a decent illustration of how rotating the housing will affect caster and pinion angles.