new springs equalled lift

[thistle3585]

I just replaced what I believe to be the stock springs with new, used ProComp springs on my CJ5 . Although I did not take any measurements prior to the swap, it appears that I gained about 1.5" to 2" in lift from the new springs. I'd say 1/2" of that came from the new shackles. So, I'm now looking at the drive shaft and thinking, "Is that too steep of an angle? How did that look before I put the springs on?" Hence, the lesson that you should take a measurement prior to such a job. So, my question is how much is too much of an angle on the drive shaft? How much play should be in the shaft to account for that 2" of lift? I have heard pro's and con's on using shims. Any ideas on a Jeep that will just be used for road driving? I haven't replaced the front springs yet, but will be doing that in the next week or two, so I don't want to do the job then come back and have to disassemble them and put shims in.

Also, there were no shims or spacers of any sort in the original setup.

 

[Torxhead]

You can take your newly lifted Jeep out for a drive to check for vibration at that rear driveshaft. If you look at 2" lift kits you will probably notice that they do come with shims and lowering spacers for the Transfer Case .

 

[thistle3585]

Thanks. I did not intend to lift the Jeep. I pulled these springs off a Jeep in the salvage yard and there were no shims on it, and I don't know if there were any spacers on the Transfer Case . I guess I'll drive it and see what happens.

 

[Old Dog]

I guess I'll drive it and see what happens.

That's the only real way to tell for sure.
How long are the new shackles center of bolt to bolt.
I would think the driveshafts would be ok, but when you install them make sure you have 1" or more extra each way.

 

[thistle3585]

The new shackle is only about 1" longer than what was on there and I understand that an inch in a shackle means 1/2" in lift. The lift happened going from flat springs to new, arched springs.

 

[Petescj]

My 78 CJ5 with 2 in springs and a small shackle lift needed a 1 in Transfer Case drop. Drive it and see but "usually" a CJ5 will need one with all else left the same.

 

[thistle3585]

So, do you drop the Transfer Case , shim the axle or both?

I got it put back together tonight and took it for a test drive. There was a little bit of a shudder when accelerating from a stop but I think that was more me than the Jeep. I haven't driven it for two weeks. It drove fine, so I'm guessing there isn't an issue but the drive shaft angle looks vicious to me. I'll keep an eye on it and go from there.

 

[thistle3585]

I know it probably feels like you guys have to hold the hands of the new guys, but we do really appreciate your knowledge and experience.

I enclosed a photo of the drive shaft. The angle concerns me, but also the amount of driveshaft that has been exposed with the lift. The red arrow shows what has now been exposed as a result of the lift. How much additional length should there be?

One other question related to this. When I removed the jacks from the axle, and the axle was hanging free on the springs, they hung about 1/2" below the shocks which were fully extended. I had to jack the springs up to get the shocks on. I am assuming that the shocks are too short, so I am going to buy new shocks. Is there a rule of thumb on how much longer they need to be? I assume that the axle can't be forced below the point in which it hangs free on the springs.

 

[Old Dog]

I enclosed a photo of the drive shaft. The angle concerns me, but also the amount of driveshaft that has been exposed with the lift. The red arrow shows what has now been exposed as a result of the lift. How much additional length should there be?

Go down to lowes or home depot and ge an angle finder they are only $10 or so. Put it back on jackstands and let the axle hang free (disconect your short shocks and driveshaft) if the angle is over 20* you should think about getting a double cardon shaft. Now see if the driveshaft has enough lenght to connect back up if not you need a longer one.

One other question related to this. When I removed the jacks from the axle, and the axle was hanging free on the springs, they hung about 1/2" below the shocks which were fully extended. I had to jack the springs up to get the shocks on. I am assuming that the shocks are too short, so I am going to buy new shocks. Is there a rule of thumb on how much longer they need to be? I assume that the axle can't be forced below the point in which it hangs free on the springs.

sounds like they need to be longer but be sure they won't bottom out when the springs are compressed.
Yes they can be forced down farther when it's flexed, but that depends on the springs.

 

[Petescj]

Get me a measurement for the shaft you need. I may have one with a double cardigan.

 

[thistle3585]

Where do I measure the angle? I thought I would measure the angle on the driveshaft?