86' CJ-7 Laredo Suspension Lift Questions: Need Advice

[OneBadMudder]

Okay, so I'm trying to get a little bit of advice before I start trying to install a 4" BDS suspension lift on my 86' CJ7 . First of all, it has a Dana 30 front, Dana 44 rear 2.73 gear ratio (getting that changed to 4.10), Dana 300 TC.

I want to make sure that the driveline is angled properly, but am not too sure about how to accomplish this. I know that I can order a tom woods cv driveshaft, and will probably need to have the spring plates re-positioned on the axle tubes.

Will I need to get a SYE like i did on my Jeep TJ? What is the procedure for lining up the pinion angle / re-positioning the spring plates? I'm sure this stuff is covered somewhere on this site. Anyone know of any good threads that have a detailed install? Thanks in advance for your input!

 

[Torxhead]

Tom Woods provides a "Driveline Geometry 101" which is quite boring and hard to read. You might want to check that out for a better understanding of modifing a CJ driveline, it not really that complicated. To properly design a driveline setup with a 4" lift, it will take rotating the pinion angle to almost match the driveshaft angle drop, then into a cv joint. So you will not have to lower the Transfer Case . I had the existing driveshaft modified to accept the cv joint to try and save a few bucks. The front axle should be rotated in a similar way to provide proper steering alignment.

 

[Jimbos76cj]

Okay, so I'm trying to get a little bit of advice before I start trying to install a 4" BDS suspension lift on my 86' CJ7 . First of all, it has a Dana 30 front, Dana 44 rear 2.73 gear ratio (getting that changed to 4.10), Dana 300 TC.

I want to make sure that the driveline is angled properly, but am not too sure about how to accomplish this. I know that I can order a tom woods cv driveshaft, and will probably need to have the spring plates re-positioned on the axle tubes.

Will I need to get a SYE like i did on my Jeep TJ? What is the procedure for lining up the pinion angle / re-positioning the spring plates? I'm sure this stuff is covered somewhere on this site. Anyone know of any good threads that have a detailed install? Thanks in advance for your input!

I would install the lift and drive it to see how it does.. 4" is seems to be the cross over point for needing to drop the T/C and turn up the axles. IF your not doing some crazy offroading where grong clearence is critical then I would install the T/C drop and run a degree shime in the rear axle. If you do need to get a double cardan shaft the axle set up is different from regular shaft.

With stock drive shaft you wantthe angle of the Pinion yoke to be the same as the T/C out put. If the Out put is at 5* down you want the rear end to be 5* up.

For a Cardan shaft you want the rear end angle to point right at the rear out put, find the angle then subtract 2*. so if a dowel placed from the center of the rear out put to the pinion nut on the rear yoke was at 8* you would want to turn the axle up to 6*

As for the SYE you should have the Dana 300 for a T/Case... it has a fixed yoke and the slip part is in the drive shaft. For the front shaft you can grab a double cardan shaft from the front of a waggy or j-truck and have it cut down to fit you rear length.. they are heavier duty and already have the double cardan joint built in. You will need to buy a double cardan yoke for the Dana 300

26ZCV131 - Tom Wood's Custom Driveshaft - 1310 CV Yoke 26 Spline For Dana 300 For 1980-86 Jeep CJ : Tellico 4x4

If it were me I would install the lift with a set of 4* shimes and no Transfer Case drop and see how it does. If it vibrates drop the Transfer Case then try. if its still no good go to the tom woods shaft.

 

[OneBadMudder]

would a drop pitman arm correct any steering angle issues that might come with a 4" lift, or is that just a cheater way of doing things?

 

[Torxhead]

A better way would be to reverse the drag link.

 

[diddy2003]

I am using the T/C drop on my Jeep. Seems to be working fine. It definitely helped on the angle. No issues now.

 

[OneBadMudder]

Doesn't the TC drop just take away ground clearance under the body of the jeep?

 

[diddy2003]

Doesn't the TC drop just take away ground clearance under the body of the jeep?

I guess technically it does. But, it drops it maybe an inch in the middle of the jeep. I am not worried about an inch there to be honest. The Skid plate doesn't come down too much IMO. It was the cheaper solution vs Tom Woods and other options. No Vibs and it works well.

 

[Old Dog]

Yea what Jimbo and Torxhead said.
I run a 4" superlift, I used the shims that came on the rear springs
with NO t/c drop. I didn't want to loose any ground clearance.
My shaft was at about 12*
It did fine at 55mph. I never really drive my cj any faster than that
so not sure about anything faster.
Oh yea, use steel shims not alum. or better yet reweld your perches.

 

[Jimbos76cj]

would a drop pitman arm correct any steering angle issues that might come with a 4" lift, or is that just a cheater way of doing things?

No its not a cheater way.. you want the drag link to be as close to paralel as possible. Cheating would be a Z bar..

A better way would be to reverse the drag link.

Not sure what you mean by reverse the drag link? Ive heard of Tie rod flip but never reverse the drag link.

 

[Old Dog]

Not sure what you mean by reverse the drag link? Ive heard of Tie rod flip but never reverse the drag link.

I'm thinking that is what he ment.

 

[Jimbos76cj]

I'm thinking that is what he ment.

Tie rod flip won't change the steering linkage. It move the tire rod to the top o the arms to allow more clearance.

 

[Old Dog]

Tie rod flip won't change the steering linkage. It move the tire rod to the top o the arms to allow more clearance.

If you also flip the drag link you don't need a drop arm. Heres mine with a 4" lift and a stock pitman arm.

 

[Dan86CJ7]

old dog, what flip kit did you use? also did you flip the drag at the pitman end also..tks

heard flip is better

 

[Old Dog]

old dog, what flip kit did you use? also did you flip the drag at the pitman end also..tks

heard flip is better

I used the reamer and inserts from Rocky Road because my buddy already had the reamer. If I was to do it again I would use the kit from "go for it"
I'll look for the link if you need it. There was a good thread by Sasquach awhile back.
No you don't flip the pitman arm end just the other 3 at the knuckles.

found the thread http://www.jeep-cj.com/forums/f19/tie-rod-flip-10552/