Need add-a-leaf advice

[Test Guy]

Installing a lift on an 88 long bed that I rescued on it's way to the scales.  I have a set of Rusty's 3.5" full length add-a-leafs to install.  Does anyone have experience with Rusty's add-a-leafs to know if I can expect to get 3.5"?  The leaf doesn't look any beefier or arched then the stock leafs when removed.

 

I also have a short 2" add-a-leaf from another manufacturer.  What amount of lift might I expect if I installed the Rusty's 3.5" as well as replaced the overload spring with the 2" short add-a-leaf?  Anyone done that sort of pack before? 

 

I also have an extra set of RC shackles that could give more if I don't get what I need out of the add-a-leafs.

 

Any recommendations?  (Other than full packs, for now)

 

Thanks

[Eagle]

Is Rusty's AAL rated for 3-1/2" in an MJ, or in an XJ? If it's the latter, expect about an inch to an inch and a half less lift in an MJ.

[Test Guy]

It was not application specific on the site so I called Rusty's to ask.  They seemed to understand the differences between XJ and MJ leaf springs and said that I should get very close to 3.5".  I'm still cleaning up the old springs so I have not put them back together.  Just wondered if I might be better off to go ahead with the short leaf and the Rusty's leaf to try to get 3-4".  I have RE 4.5" coils and control arm drop brackets for the front.  This is my first MJ.  All my experience has been with XJs that were also DD's.  Thanks.

[Eagle]

Rusty deals mostly with XJs, so unless it says the AAL is for an MJ, it's rated for an XJ. XJ springs start out nearly flat, because they are SOA from the factory. MJ springs start out with an arch.

 

For reference: Rancho also lists the same AAL for both the XJ and the MJ. Unless they have revised their catalog, the listings claim 2-1/2 inches for the same AAL in either an XJ or an MJ. I wasn't buying that, so I called Rancho, and eventually I was connected with a product engineer. She understood my question, but she didn't know the answer. She put me on hold and went off to talk to someone else. Eventually, she came back and said that the AAL generates 2-1/2" of lift in an XJ, and about 1-1/2" in an MJ.

 

Based on that, for Rusty's AAL I would expect to see 2" to 2-1/2" in an MJ. If you're looking for more than that, go ahead and try it with both the long and short AALs. But I wouldn't scrap the overload leaf -- it's also useful to control spring wrap.

[Test Guy]

That's about what I suspected.  Thanks for the input.  I will post the outcome for future reference.

[Test Guy]

Just FYI, the Rusty's "3.5 inch" add-a-leaf gave me about 2.25 inches of lift.  Guess I will add the shackles to get the rest in the rear.  Figured the 3.5 was for an XJ but trusted the guy I spoke with on the phone at Rusty's.

[Eagle]

Figured the 3.5 was for an XJ but trusted the guy I spoke with on the phone at Rusty's.

Remember what Ronald Reagan said: "Trust, but verify."

[86FUBAR]

FWIW when I purchased my first lift for the mj about 14 years ago the 4.5" lift was specifically for a xj as there was only one lift specially for the mj and I couldn't afford it . It came with AAL rear which I installed and they worked just fine leveling out the truck with the front and are still under the back to this day in a spring over configuration working just fine .

[Incommando]

Short add a leafs have a bad rep especially if they are for a moderate or better amount of lift. It seems they do not naturally conform to the original spring packs well enough and that they place the pressure points for the lift in the wrong places on the original spring pack. Just something for someone looking to use short AAL's to maybe research before doing so.