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five-string 09-04-2010 09:26 PM

Bastard Pack S10 Springs on YJ Build Thread


So, I am going to attempt the famous S10 bastard pack mod. The first photo above is how it looks today with supposedly 2" lift shackles. The next photo below shows how the Jeep sat with same tires before I added the longer shackles. This was the day I bought it. The front tire has been changed to match the other three and I turned the white letters out......

As you can see, the stock leaves are almost straight. No shame for them, thought. The jeep has 239,000 miles on it.

And the shackes I installed a few months ago are just not what I want. Can you say Buckey Beaver?

For reference, I have 23" from ground to body in the back and 30" from ground to fender in the front.

So, I went to the local bone yard and retreived four rear spring packs from two S10 donors. These came from a mid '80 and around '90 2WD trucks.

I cut the eyes from the ends at the junkyard but kept the center pins in till I got home to keep the packs organized better.

five-string 09-04-2010 09:42 PM

Getting started
My goal is to remove the stupid looking shackles, reinstall the factory shackles and gain about 2" of lift from where I started, i.e. I would like 25-26" on the rear measurement and 32" or so on the front.

I removed the center pins by clamping the packs then unbolting them. Then the clamp can be released gently.

Here's what the S10 packs look like once disassembled.

Even though I cut the eyes off the S10's, the main leaf is still pretty long, at just over 48".

I removed the stock spring pack from the left rear of the YJ. Liquid Wrench is my friend.

five-string 09-04-2010 10:09 PM

Here is the center pin/bolt on the YJ. I disassembled the pack the same way I did the S10 packs.

Hmmm. The lower bolt is from the S10, the upper one is from the YJ. I will need to purchase a longer bolt since I am adding S10 leafs and don't plan on removing any YJ leafs. I will get bolts in the smaller YJ diameter.

The YJ springs are significantly shorter at right around 45".

I also discovered that the S10 springs do not have the center hole in the, uh, center. One end of the leaf is slightly longer than the other, measured from the center hole. All the S10 leafs appear to be about the same thickness and arch, so I chose to use the second longest S10 leaf. I cut it to almost as long as the YJ main leaf. I had to cut off a little more on one end than the other. I used a 4.5" angle grinder with a cutoff wheel.

That's all for now. I will update as I make progress.....TTFN :wave:

06camarodude 09-04-2010 11:06 PM

Thinking of doing this to my YJ, I could really use a couple extra inches of clearance for the 31's under mine. I don't think the PO did any kind of lift before the tires were installed. Curious to see what kind of results you get with this. I'm planning on installing my 1" lift boomerang shackles and a small body lift at the same time. It looks relatively easy judging by your posts so far.

Keep up the good work, and let us know how it works out!

five-string 09-06-2010 12:07 AM

Day 2
Cutting the S10 leaf to size. If you do this job, have some spare cutting wheels around. They only last for about 1 spring cuts. That spring steel is some hard stuff.

I used a bench vise and a big pry bar to open up the stock clamps on all the packs. On the rear springs I just squeezed them back together somewhat after swapping out leafs (leaves?) but on the front ones I tried straightening out the top tang of the clamp. It ain't easy but a large hammer and some perseverance got it done.

Here is a pack ready for reassembly. This is the left front spring. I added a full leaf and replaced the second YJ leaf with another S10 leaf (including the nice clamps on the ends) because the front end was originally sitting an inch or so lower than the rear so I want to try to get it close to level. It's a guessing game as to which leafs you use and how many. Here's an interstin' piece of info: the original YJ springs measure .260" thick (just a hair over 1/4"), and the S10 springs come in at .325". Not a huge difference but enough to suffice. The two white-ish leafs are the S10's.

A rebuilt pack ready for install (rear). I made new center pins from grade 5 bolts and ground the heads round.

This is what it looks like installed. This is the right rear. You can see the full leaf I added right under the main YJ ply. You can see just a little difference in thickness.

A note on extended shackles. As I was preparing to start on the front end, I noticed my front two shackles were bent and the front springs, diff and all had shifted toward the driver's side by about 1/2" or better. I haven't gone off road at all since I installed them. They just bent from road use. Do ya think this might cause a slight hanling problem at highway speeds!? Getting rid of these should make her handle way better on the road.

I hereby take an oath, I will never, ever use lift shackles again as long as me and my Jeep shall live. Amen.

So, how much lift did I gain, you say? Patience, Glasshoppa. Patience...

I measured the rear while the extended shackles were still installed and I netted right at 3" of lift. In other words, if you do this mod and don't change anything else, one S10 ply will give you roughly 3" of lift. I removed the piece-o-crap shackle and I still got 25" to ground for a final 2" lift from where it was before I did this upgrade.

The front, I have only one side installed and need to get to the bone yard for some oe shackles as I cut a couple of mine up installing the new junk. But I measured it with one oe shackle in place and I got 3" of lift there.

The fronts are a bit more difficult to get everything lined up for reinstall. I ended up unbolting the shock so I could lower the front diff far enough to hang the spring pack on the axle saddle first then bolt it to the spring hangers.

Combining an additional leaf on the front along with swapping out a YJ leaf for a thicker S10 leaf, my front u-bolts are not going to be long enough to get the nuts on the u-bolts fully. So I will be finding a spring shop to get some new front u-bolts made.

It just happened to work out that I could have gotten by with just two S10 Springs instead of four. Each S10 pack had three plys plus a honkin' big helper spring. I used one middle ply on each rear pack and then a main ply and a lower ply on each of the front packs. Who knew.

I will post some final pictures of the Jeep once I get that last front spring done along with a preliminary road test report.

medic-11 09-06-2010 06:49 AM

Good information and well presented too! I might do this myself one day. Please report back about ride quality when your done.

five-string 09-06-2010 08:50 AM

Thanks for the comments. This is a tight budget build as I don't have the extra cash to throw at the Jeep like I wish, but a lot of other folks are I are tightening their belt these days. So far I have $50 in this project. I will have a couple more $ in a couple oe shackles and some bolts but the whole thing will come in under $75.

I will recommend to others, this is a perfect time to replace old bushings and it would be a good idea to use all new u-bolts.

Tools needed:
big prybar
4" grinder with extra cutoff wheels
safety glasses (a must have item, I have been to the eye dr. twice in my life to remove bits of metal from my eyes because I am a dufus)
large bench vise
big hammer
C clamp
jack stands
wheel chock
PB Blaster, WD-40, or you favorite spray lube/rust eater
sockets, breaker bar, ratchet, etc.
vise grips
usual array of misc tools
cold beverage(s) of your choice

The bigger the vise, prybar, hammer, etc, the better.

I hope to update this thread tomorrow evening as I should be able to finish it up by then. I took a test ride when I got the back end done. It's amazing how much you will notice 2" of lift. The ride was very good but the real test will be once all four corners are complete so I 'll wait till then to pronounce victory.

Mean Max 09-06-2010 09:11 AM


Originally Posted by five-string (Post 10077049)
As I was preparing to start on the front end, I noticed my front two shackles were bent and the front springs, diff and all had shifted toward the driver's side by about 1/2" or better. I haven't gone off road at all since I installed them.

The reason is because you still have a track bar. By lower the axle/raising the frame to a new position, the track bar is at a steeper angle which effectively shortens it. This draws the axle to the driver's side.

Ditch the track bars, front and rear.

Nice write-up! :thumbsup:

Max :cheers2:

five-string 09-07-2010 10:38 PM

Thanks, Max. That is some new information to me. I am planning on removing the track bars eventually but want to get this mod finished and test drive to see what it is like. That way if something isn't right I know it wasn't the track bar removal that messed me up.

I finished up the lift tonight. Having a hard time typing. I squished my little finger pretty good on the stupid sway bar, of all things.

I measured again and got 1" final raise on the rear and 2" on the front. Now remember, I removed 2" lift shackles in the midst of adding leaves so your results may vary and probably will. I am guessing I would have gained 3-3" on the rear and 4" or so on the front had I left the shackles alone.

Things that would have made this job easier:

Air tools, especially a " air impact wrench
More than one small floor jack
Air tools
a small bottle jack to help line things up when bolting everything back up
A buddy to help line things up
Air tools (hint to wife)

One other tool that proved very handy, a nylon ratchet strap, like the ones used on flatbed trucks to hold down cargo. I used one several times to help pull axles or springs just a little to line up bolt holes etc.

Too late for a test drive tonight. I will take her for a spin in the morning and post results. And 'after' pictures.

five-string 09-08-2010 09:51 AM

Here are some pictures of the Jeep after all is finished up, well almost all...
('scuse the chickens, they are nosey)

It may not appear as much of a lift to most people, but I am 1" higher in the back and 2" higher in the front. Exactly the look I was going for.

Driving: First, I don't need a Cadillac ride from my Jeep. I like it feeling a little on the stiff side as opposed to soft or squishy. If I want a smooth ride, I'll get a sedan. So....

I can notice more of the little bumps in the road than before, but handling is much tighter than it was due to those long shackles that were up front. I could not find any OE shackles in the junkyard (I still need 3 pieces) so I cut down the junk lift shackles and drilled new holes to get it on the road till I locate some. Once those OE shackles are installed on the front, I will lose maybe " or so of lift there.

No noticeable vibrations from driveline angles, etc.

Over all I am very pleased with the outcome and am glad i did it. It isn't hard in a technical sense but it is a lot of hard work and sweating and a dirty job. I would do it again if I bought another YJ needing spring help.

One question, what is the best thing to do with the clamps sticking up on the front springs? I read where some guys will drill a hole and mount a bolt through there, leaving space for the springs to move. Other folks bend them shut. Opinions, please.

Now my 31/10.50/15 tires look a little small. I am in the process of getting some 32/11.50/15's and white spoke 'wagon' wheels for her. Should be sweet.

Louie4 09-08-2010 11:53 AM

This is an awesome write-up. I've seen tons of questions on making bastard packs out of S-10 springs but I've never seen it done. Looks like it's a decent setup for the price as long as you don't mind getting dirty. As for the clamps I would cut the very front ones down or off and clamp the one behind it. I would also recommend putting some new bushing in those stock spring eyes since it's all apart anyway. You also need to chunk the track bars. For shackle length I wouldn't go more than 5" eye to eye but that's me. Looking good.

Destr0 09-08-2010 12:27 PM

Nice write-up. Saves me the trouble as I was planning on pics and a write-up when I do mine. I will be going for a bit more lift than you by replacing most or all of my YJ leaves (except the main one) with the S-10 leaves. I am shooting for 3-4" of lift. All my parts are here, just waiting on finishing up a couple other things first.

As for the clamps- I would cut off the shorter one and add a bolt across the longer one in the pic above. Leaving them open will give you more flex off road, but you do not want them to be able to slide over the top of your clamps. I did it this way on my XJ bastard packs and it made a noticable difference from when I first set them up (and clamped them down).

Cheers and nice looking Jeep!


Castr8r 09-08-2010 07:27 PM

Great writeup! Cheap lift, lotta work. Some better-late-than-never advice: U bolts should be available at your local farm supply store and at auto parts stores. Check the size in the package; it will probably not be the same as it's labeled. And, like was mentioned before, ditch the track bar as it serves no useful function.

five-string 09-09-2010 02:38 AM

Thanks for the compliments. I will take the track bars off directly. And I am going to TSC and look for clamps.

Destr0, you won't have any problem getting 3-4" of lift. I would have had 3" or so had I kept the same shackles and I only added one leaf all the way around and replaced one of the stock ones up front on each side. If you used all the S10 springs I imagine you would get 5-6", maybe more.

I took the Jeep to work last evening, a 40 mile one-way trip. I can say the truck springs do stiffen things up a bit, but I like it that way. It feels ready to take on more than just some asphalt. And at 60 mph I can feel the slightest vibration from the driveline angle. If you didn't know the vehicle like I do, you probably wouldn't notice it, but I will be dropping the t-case a wee bit very soon.

Side by side of before and after with the same tires and shackles...

BrockGrimes 09-13-2010 09:26 PM


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