MAF lift shackles

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Sep 2, 2007
I am planning to get a set of the Man-A-Fre Greasable HD Anti-Inversion Shackles. I currently have a 4 inch Skyjacker lift kit on my 40 and I am running 35x10.50R-16LT SSR Radial Tire by Super Swamper on TRD Trail Team wheels. I have alot of wieght on the rear of my 40 and was looking for for a little more lift on the rear to get a little more clearance and to level my 40 front to rear. I know that the stock shackles are 2 3/4 inches pin to pin. So my questions are:

1) How much lift will I really get with extended shackles? To clarify if I go from stock 2 3/4 to 3 1/2 will I really get 3/4 more lift or from stock to 4 3/4 will I get a full 2 inch lift?

2) Is there any thing else I need to look out for other than brake lines, such as castor or drive line angles? If so what is the best corrective action?

I have never used extended shackles so I don't know what problems they may cause. I was looking at the 3 1/2 for the front and 4 3/4 for the rear but that depends on the answers I get back.
1) Ratio is 2:1 after the 2 3/4".. you will gain approx. 3/8" of lift with the 3 1/2" shackles.

2) You won't see any difference IMO with the 3 1/2" shackle over the 2 3/4".. but going longer (4"-6") creates steering (ON FRONT SHACKLES) issues that need to be corrected with shims to get you back to a good angle degree. Rear shackle angle will become more vertical the longer you go and will give you a rougher ride.. But then again.. you are running a SkyJacker so you are use to that feel/ride already..

Pin failure is your enemy on LONGER shackles.. especially cheap India or China made ones...

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Anything above about a 1" increase in shackle length is going to affect your caster angle. I have shackles on my truck that were only about 3/4" over stock (less than 1/2" lift) but they changed my caster angle from about 1 degree positive to about 0.2 degrees positive. I definitely felt it in the steering. I'd plan on caster shims.
Given the choice and your goal of just raising the rear I would stay stock up front and just lengthen the rear. If you want an inch then add two inches of shackle. If you lengthen the front then you need to determine the castor correction afterward.
I had lift shackles on the rear of my '74 and never knew I had a caster problem for many years. I just thought the wandering in the steering was "normal" for these vehicles. Wasn't until I tried flat towing it I discovered I had a problem. When making turns while towing the 40, the wheels would not track and turned the opposite way.

I researched the issue here on MUD and fixed the problem by switching back to my original shackles and added caster shims on the front axel (was -2 degrees and is now +2 degrees). It now tows correctly and drives like a brand new car! I've had the vehicle since 1984 and wished I found this out sooner. Oh well, better late than never...

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