another lowering question

[chevy99]

Hey guys have another question.Once i lower the back of this 79 four inches do i have to worry about the pinion angle or am i OK? Thanks for the info.

[rwhit57]

With a 4" drop the pinion angle doesn't change enough to cause any vibration problems that I know of. I have ran into driveshaft length issues when flippin the rear though.

[Captkaos]

Are you doing a shackle/hanger for the 4"?  If so, 98% of the truck I dropped with that method requires shims.
I have never had to shim a flip kit.

[chevy99]

Yes i am doing the shackle/hanger kit.Where do the shims go on this kind of set up?Thanks.

[Captkaos]

under the axle.

[got2haul]

The angle resulting from my hanger/shackle install was severe, so I had to use a 6-degree axle shim.  (When I did a '92 C1500 a few years back, I only had to use a 2-degree shim.)  The pictures below show the story.  The first shows the severe angle before the shim.  The second is a picture of the left side saddle with the shim installed, looking toward the rear of the truck.  The third picture is a side view of the same axle saddle (driver's side).  The front of the truck is to the left.  The fourth picture is the corrected driveline angle.

[got2haul]

And here it is with the rear half of the frame wire-brshed and painted.

[got2haul]

CORRECTION:  I said in the caption for picture 3 that the front of the truck was to the left.  It's to the RIGHT in the picture.  (I keep forgetting that you can't modify a message when you've attached pictures this way, too!)

[chevy99]

OK, the question now is there different shims with the kits? Also what about lowering springs and do you need shims with these? Trying to get this right because the wife wants this truck done asap! Hard on one income and family, thinking possible second job.

[Captkaos]

Generally speaking no shackle/hanger kit comes with shims that I have ever purchased.

[chevy99]

Thanks for the info so how do you know what degree shims you need? Also do you know if you need them with the lowering leaf springs? Just wandering if it is worth the trouble or i need to take it to the shop.Thanks

[Captkaos]

you need an angle finder to measure the angle of the driveline.

[chevy99]

Do they have a standard angle or do i need to measure the factory angle before installing the kit? What about moving the axle brackets to the bottom of the leaf springs? Thanks so much.

[Captkaos]

It needs to be around 3-4 degrees.  There is a whole post on this if you search but to make it easier measure what you have and then make it close to the same when you are done.

[chevy99]

Thanks so much! We will see what happens.Where can i find a 1 1/4" front swaybar that goes in the factory mounts? I believe the option was a f58 mine is a f59 1 1/8". The after market ones that i have seen use bolt on swaybar lenks and i would like to use the saddles instead.Thanks.