Bds Lift Question

About to pull the trigger on the 2.5" kit for my 71. Do I need to extend bump stops? Do I also need shims?

Any insight would be great!

cheers

 

I didn't but it's probably advisable.

You should check your alignment when done, you may need caster shims.

 

which bump stops did you use?

 

Likewise, I don’t have extended bump stops…and I have the longer BDS rears fitted up front. Flexes pretty well. No issues, but I’ve also got extended / longer shocks. Put it together, do some flex tests and go from there.

As far as shimming goes, you’ll have to put it together and take measurements. You’ll want your caster at 6-7 degrees positive. Toe-in around 1/8” - 3/32”.

Lastly some folks have had issues getting the correct U bolts with this kit. All the different ECJ-intermediate axles have different tube diameters. If you have the stock axles (Dana 27 front - and 44 Flanged offset rear) you’ll need 2.25” bolts for the front and 2.75” for the rear IIRC. Measure your tube diameters to verify.

 

I've read up on the u-bolt issue, so that's another good call that I'll need the 2.25" front bolts as they seem to be the issue.


I'm less worried about bumping when flexing as that would be more low-speed. More inclined to worry about FS road holes, etc.

 

Sounds like you’ve got it figured out… but just remember the common ECJ5 tapered Dana 44 has a 2.5” tube diameter. I believe yours (70-71) is like the intermediate 44s: 2 3/4” tube. So just another potential point of confusion.

 

I'm hoping BDS has 3-4 early CJ kit packages for a reason, but we will see

 

Used the BDS 2" lift kit on my son's TJ. Don't remember using the extended bump stops. Probably 14 years ago.
It has worked great.
Took it straight to the alignment shop after install.
Dave

 

does anyone know what width shim works? there are some off-the-shelf versions that seem compelling.

 

I did a 2.5" bds on my 70. I ended up getting 7/16 ubolts due to the ones that came with didn't fit without major drilling to my spring plates.
I bought 6 or 7 degree caster shims from warrior products. They were 2" wide, springs are 1.75" wide so minor grinding with an angle grinder was needed, no big deal.
I used the original driveshafts and bu.pstops and have never had an issue. I live the shocks that came with it too.
I will never by anything but BDS suspension products for any ECJ I own. Light-years better than the rough country I bought.

 

ECJ5 and Intermediate springs are 1.75” wide unless someone has changed the springs to something else.
WFO has nice steel shims. WFO

It’s a little bit of a pain to to put it together and take it apart again…and folks can guess…but you won’t know the caster for sure until you put it together and measure. Suspension work often takes a bit of trial and error to get things just right.

Good insight on bolt diameter / tie plates above.

 

I'd almost rather shoot for "close enough" on the first attempt with a 4 or 5 degree shim and have the jeep mostly driveable than have to redo everything after the fact in case the caster angle is way off and you have to tear everything apart again. Does that logic hold?

 

I’m sure plenty of guys have done just that and it turns out fine. You’ll know pretty quick after the first drive.
Are you also replacing the shackles?…a slightly longer shackle will also reduce caster…tilts the pinion up a little.

 

I planned on using the factory shackles, but I’m open to opinions. I know that shackle lifts aren’t generally great but if it helps accomplish two things (more lift and caster help) maybe that’s a better option?

 

A slightly longer shackle will let the longer spring travel a little further. And I think you might need rear shims to account for pinion angle, you might get a little DL vibration at speed. I have never needed front shims with a 2-1/2" lift, I think the caster change is minimal.

 

Yes, like Tim said a little longer would increase articulation. 1/2 -3/4” longer or so. And so 3.25 inches between bolt centers. Stock is 2 3/4” off centers. Any more than an inch over stock length is generally considered too much. Longer shackles are usually “bad” for caster….contributes to negative caster, sometimes requiring a correction. You will get 1/2 the length over stock in lift.

A nice aftermarket shackle would be stronger. Not sure what’s out there right now… I’m still running the old Con-Fer shackles. Maybe someone will suggest something.

Edit: For reference, I have about 3.5” in suspension lift and run 6 degree shims for 6 degrees of positive caster.

 

Your Purple thread says you have a Dana 20 transfer-case. Is your rear pumpkin centered in the axle? What front end do you have...Dana 27 or 30?
If the rear is centered there is a good chance you will get the correct though 1/2" u-bolts for the rear. If the front is a D-27, you might as well order
the Rancho RS714 as the u-bolts that come with the kit will be 1/4" too large and BDS does not have the correct bolts. These are also 1/2" diameter
and will require enlarging the holes. A die grinder works well for this and you want to maintain the inside or spring side of the hole if using the stock
spring plates. WFO Concepts makes 1-3/4" shims in 2,4,6, and 8 degrees. If using the stock length shackle, I would go with 4 degree just cause. If you
do have a centered pumpkin rear and a Dana 20, you will likely need shims in the back as Tim said. This will also help with the nose down effect BDS
springs have. They need about 1" more arch in the front springs. The Fox shocks are nice and can be mounted with the body of the shock up to give
more clearance at the bottom. Stock length shackles are 2-3/4" from the center of the holes. I would not go more than 1" longer for 1/2" of lift. The
spring center pins are 3/8" and the shims will need to be drilled out. The centering bolts will be close on the length with shims. All I got...Good luck.
Edit: Even with 5" bump stops, I doubt you will be close to hitting on them.

 

I put BDS springs on my '71 a couple years ago. The bolts in the kit I ordered were correct for the flanged D44 rear and D27 front.

I did 6 degree caster shims while I was at it because it can't hurt. I didn't like how the front sat lower than the rear, so I made 1" longer front shackles and used the stock rears. Some of my front sitting lower is due to the caster shims, some is due to BDS.

Front shackles:


Shackles and caster shims installed:


Final ride with longer front shackles and 32 inch tires:


I put XJ Cherokee bump stops in both ends. You can slot the holes in them and they will literally bolt on. The fronts help keep the wheels out of the fender enough to turn at full flex. The rears never touch even with the longer bump stop.

XJ bump stop installed:


Flexed out onto the front XJ bump stops:

 

Right on. I never get tired of seeing your Jeep on that landscape. Jeeps, actually.