its a 77 150, im relifting the rear of the truck cause the po went the cheap route. im going with bronco graveyards 5 1/2 inch leaf springs and all new hardware and shocks but im curious what degree shim to use with that kind of lift? thanks

 

Is the truck a long or short bed? Long beds to my knowledge don't need shims. I've got 6.5" lift on the rear of mine and I haven't had a single issue yet.

 

its a short bed. i wouldnt have thought of that, but it makes perfect sence. i dont know that i have to have a shim but there cheap and i want to do it the best way possible to avoid issues later.

 

The driveshaft angle at the pinion and the angle at the t-case output have to be the same angle (well, opposite... sort of.) Let's say you have 2* at the t-case. You must also have 2* at the driveshaft. Otherwise, you get a nasty vibration. Let me demonstrate through a crude picture:

This is the t-case "l"
This is your drive shaft "\"
And this is your axle pinion "L"

Your driveshaft should have the equal (but opposite) angle:

l
\
.L

Like that, but I'm trying to work with letters and symbols, so it's not the best example lol

 

ok with that being said there has to be a fairly decent amount of +/- in the fact that they have to be the same degree. givin into consideration the movement of all the parts? right?

 

If I recall correctly, it has to be within 2* of eachother. They have to be at least 2* from being a straight shot also to keep the u-joints moving. You may end up needing to rework your t-case mounts if you lift it too high, but I don't know where the "too high" point is.

 

thanks for the info. i guess since the truck is already lifted 5-6 inches without any issues then i wont worry about the shims at this point.

 

If you are running U joints, then the pinion needs to be parallel with the transfer case. (Although I have never have felt any vibrations from having the pinion angled up a little.)

If you have a double cardan joint at the transfer case, then you'll want to point the pinion directly at the transfer case.

The Best way to accomplish this is not with shims but with a grinder, or plasma cutter and a welder. Cut the welds off of the spring perch grind it smooth, and re-weld with the pinion pointed in the proper direction. That will take a little more time, but it comes out cleaner, and offers more adjustability.

Pirate4x4.Com - Extreme Four Wheel Drive

 

I have a 96 bronco with 7in lift. Keep destroying my driveshaft . The rear end angle is off what degree shims should I us to fix this issue

 

Billy welcome to FTE, you are in the 73-79 section, try that question here.

1978 - 1996 Big Bronco - Ford Truck Enthusiasts Forums