Looking for recommendations on replacement rear leaf springs

[Bilskirnir3124]

Afternoon (or applicable time when you read this)

I have a '97 Cherokee with, about, a 2" lift on, about, 30" tires (they're metric; when they go I'm getting 30"s). I'm chasing around some suspension problems, front and rear. I know the front is a wheel balance problem because it's only there between 55mph-65mph. I do have some steering slop also, but the vibration and main problems are only between those speeds, and thus, I'm 99% sure that it's a wheel balance problem.

My rear problem is a little more... complicated. So, I can see my rear leaf springs are almost flat at rest. I have maybe and inch or two of bow with nothing in the back end. It sags even more when I have my usual arsenal of fluids and equipment in the cargo area (never needed it, but I wouldn't be caught dead without them). The right side is also a little flatter than the left.

I'm not really experienced with suspension work, but I'd like to get my options sorted out, and see if it's a job I can do myself. What is an optimal solution for replacing these parts? I like to buy once and cry once. I've seen a bunch of options out there, and I have little knowledge to help me discern what I should buy, and what I should be on the look out for. For instance: should I be looking for overload springs to add to the leaf pack? Should I consider add-a-leaf kits to add to another spring pack? What rate springs should I be looking for?

Thanks in advance.

 

[RCP Phx]

Can't help you with the rear (maybe shackles), but for the front you have signs of ( Death Wobble ) so some further investigation to do.

 

[Bilskirnir3124]

Can't help you with the rear (maybe shackles), but for the front you have signs of ( Death Wobble ) so some further investigation to do.

Yeah. I suspect I'll need to do some bushing replacement soon. The previous owner (TM) had strange maintenance priorities. I am worried about my right front wheel bearing also, though I need to get some jackstands before I can check that. Last time I had it at the shop the techs didn't mention anything.

Also, I just realized that I forgot to mention that this Cherokee is a Daily Driver, so I mostly care about good on-road ride quality more than I do about rock crawling performance. It goes off road sometimes, but it's usually through mud and dirt.

 

[Tim_MN]

What is the rear leaf spring budget?

Short overload spring leaf and extended shackles are not a good solution for saggy leaf springs. The will just accelerate the sagging. You want a long spring leaf, either a store bought add-a-leaf or a donor from a stock XJ leaf spring pack. An AAL will restore some leaf pack arch and add a slight amount of lift, and add some cargo capacity. AAL are simple to install, mix-n-match, or remove with the leaf pack still installed on the Jeep if you want to tune the lift height.

I installed a Rubicon Express 2.5" long AAL in my 1998 XJ to add some lift and correct saggy stock leaf springs. The stock had +180,000 miles on them, and now they have +290,000 miles and no sagging.

If you go with new leaf springs you will want a higher load rating. IMO the stock XJ Cherokee suspension was always too soft and squishy.


Stock XJ Springs, rear

LM - 5-5/8" free arch, load rating 605
LS - 6" free arch, load rating 675
LT - 7" free arch, load rating 755 UpCountry + 1 "

Dealer part numbers:
52000050 Standard Duty, Coded LB
52000051 Standard Duty, Coded LC, EC
52000706 Standard Duty, Coded LN, ES
52000544 Heavy Duty, Coded LK
52000707 Heavy Duty, Coded LM
52002390 Heavy Duty, Coded LS
52002392 Heavy Duty, Coded LT ( UpCountry package +1” leaf spring)

 

[Bilskirnir3124]

What is the rear leaf spring budget?

Short overload spring leaf and extended shackles are not a good solution for saggy leaf springs. The will just accelerate the sagging. You want a long spring leaf, either a store bought add-a-leaf or a donor from a stock XJ leaf spring pack. An AAL will restore some leaf pack arch and add a slight amount of lift, and add some cargo capacity. AAL are simple to install, mix-n-match, or remove with the leaf pack still installed on the Jeep if you want to tune the lift height.

I installed a Rubicon Express 2.5" long AAL in my 1998 XJ to add some lift and correct saggy stock leaf springs. The stock had +180,000 miles on them, and now they have +290,000 miles and no sagging.

If you go with new leaf springs you will want a higher load rating. IMO the stock XJ Cherokee suspension was always too soft and squishy.


Stock XJ Springs, rear

LM - 5-5/8" free arch, load rating 605
LS - 6" free arch, load rating 675
LT - 7" free arch, load rating 755 UpCountry + 1 "

Dealer part numbers:
52000050 Standard Duty, Coded LB
52000051 Standard Duty, Coded LC, EC
52000706 Standard Duty, Coded LN, ES
52000544 Heavy Duty, Coded LK
52000707 Heavy Duty, Coded LM
52002390 Heavy Duty, Coded LS
52002392 Heavy Duty, Coded LT ( UpCountry package +1” leaf spring)

That's some good intel. Thanks. The 7" free arch ones were the variety I was looking at on Quadratec. I don't know if there is a better place to look for parts. RockAuto seems to only have the 6" variety.

As for budget I'm hoping I'll be able to get out of this job with no more than $350 in parts, including greasable bushings (if those even exist, they seem hard to find but one of leaf packs I was looking at mentioned them existing so who knows), u-bolt, shackles, and other mounting hardware. I know I'll need to get a map or propane torch to get the bolts out.

 

[ChillyB]

You say you have 2" lift but springs are flat? Seems like you must have either blocks or lift shackles?

 

[Bilskirnir3124]

You say you have 2" lift but springs are flat? Seems like you must have either blocks or lift shackles?

Blocks under the leaf spring packs. And I believe there are spacers under the front coils.

EDIT: I say, "I believe," because I've been lazy and haven't gotten under there with my calibers and taken proper measurements of the spacers and blocks.

 

[ChillyB]

I think your rear problem may be related to pinion angle. If your springs are flat the axle will be more prone to "wrap" under load. This will cause vibrations. Ignored long enough, the vibes become permanent because it'll eat up the u-joints.

I think you asked about optimal solution, and also offered a $300 budget. Not sure those parameters will get us there. I'd dispense with the blocks and get a full leaf pair. That will eliminate pinion wandering up and down in elevation. Once stable see how it runs. If you still have vibes you have a decision point: do you adjust pinion angle for u-joints on both ends (keep slip yolk), or do you install slip yoke eliminator and tip up the pinion, along with a new driveshaft?


If you aren't off-roading I'd eliminate the lift components you have on it and appreciate a cool 4wd station wagon. Make it reliable. Proper lifting is RARELY addressed by whatever is marketed as a kit.

 

[Bilskirnir3124]

I think your rear problem may be related to pinion angle. If your springs are flat the axle will be more prone to "wrap" under load. This will cause vibrations. Ignored long enough, the vibes become permanent because it'll eat up the u-joints.

I think you asked about optimal solution, and also offered a $300 budget. Not sure those parameters will get us there. I'd dispense with the blocks and get a full leaf pair. That will eliminate pinion wandering up and down in elevation. Once stable see how it runs. If you still have vibes you have a decision point: do you adjust pinion angle for u-joints on both ends (keep slip yolk), or do you install slip yoke eliminator and tip up the pinion, along with a new driveshaft?


If you aren't off-roading I'd eliminate the lift components you have on it and appreciate a cool 4wd station wagon. Make it reliable. Proper lifting is RARELY addressed by whatever is marketed as a kit.

I don't know that it has enough of a lift for pinion angle to be the problem. Though it very well could be. I actually like the lift. The ride height is quite comfortable, as is the ability to do most work I need to do under it without putting it on jack-stands. That being said, I don't know much, if anything, about what the previous owner did in the lift. I'd prefer to improve what is there rather than removing it.

Here's some images of the rear left leaf spring pack.

From the front side. You can see that the spring pack's deflection under load looks almost inverted.

Here's the rear side. Completely flat under load. Sorry about the mess of trailer wires. They're on my to do list. Clearly the previous owner thought that the aftermarket diff cover was higher up.

The lift block itself. It seems to be about two inches.

 

[dktool]

Toss the blocks, buy Crown Up County replacement leaf packs and an Iron Rock full length AAL.

You will end up with 2+" of good riding, good load carrying suspension.

 

[Tim_MN]

A 2.5" Rubicon Express RE1410 long add-a-leaf will probably solve the sagging problem. At 2-3" of lift most XJ's do not need any drive line angle modifications. Most often if modifications are needed, a transfer case/transmission crossmember drop spacer will suffice.


Lift blocks bad.


.

 

[Bilskirnir3124]

A 2.5" Rubicon Express RE1410 long add-a-leaf will probably solve the sagging problem. At 2-3" of lift most XJ's do not need any drive line angle modifications. Most often if modifications are needed, a transfer case/transmission crossmember drop spacer will suffice.


Lift blocks bad.


.

So, if I were to delete the lift block while wanting to maintain the current lift height how would I go about that? Clearly the rear springs are cooked so they need to go to. May as well do the dampers while I'm down there. I was looking at the Crown 7" Free Arch as replacement springs. I don't know what shocks I should get to maintain a well mannered on-road set of suspension characteristics in the rear. You mentioned an add-a-leaf kit. Would that be needed if the rear springs are being replaced at the same time? Would I want helper springs (I've seen those mentioned around) to go with it, or are those the same an AAL pack?

Also, yikes. Good to know that blocks can do that.

 

[Tim_MN]

I have installed an AAL in several of my XJ's and in several XJ's for members of my local Jeep 4x4 Club to either fix saggy springs or to lift the suspension for off-roading. My 1998 has an RE 2.5" AAL and the original 290,000 mile leaf springs. The leaf springs were saggy but the AAL returned them to a proper arch.

If you are thinking about new Crown 7" Free Arch leaf springs, re-use the original stock XJ main leaf with the spring eyes cut off as your AAL. That should get you about +2" from the stock measurements. Keep the remnants of the old leaf springs if you want to fine tune the lift height. New leaf springs will need some time and miles to break in and settle.

I recommend DoetschTech DT3000, ARB, and BDS shocks for a smooth pavement ride and good off-road control. I cannot recommend any Rancho shocks.

You do not want a short thick overload/helper leaf.

 

[Bent]

Lift blocks bad.

Yes generally speaking. I run a 1 inch block in order to run a spring with less arch in the back. Without any anti-wrap bar the extra torque will make an ass out of the passenger side spring no time.

 

[ChillyB]

While 3" USUALLY isn't so high to have driveline issues, having a weak and flat spring pack WITH A BLOCK invites axle-wrap. So your springs may not be able to maintain pinion angle. If your pinion is hunting up and down then you cannot have a CORRECT pinion angle. Because it's wandering up and down.

Is the vibration felt mostly when rolling out from a stop? Axle wrap. Two great ways to create axle wrap: flat springs, and lift blocks.

 

[Bilskirnir3124]

While 3" USUALLY isn't so high to have driveline issues, having a weak and flat spring pack WITH A BLOCK invites axle-wrap. So your springs may not be able to maintain pinion angle. If your pinion is hunting up and down then you cannot have a CORRECT pinion angle. Because it's wandering up and down.

Is the vibration felt mostly when rolling out from a stop? Axle wrap. Two great ways to create axle wrap: flat springs, and lift blocks.

No actually. The vibration comes from the front end, roughly, between 55mph and 65mph.

The thing I think is coming from the back end is a kind of clunking noise that can also be felt a little. Most often from a stop, but sometimes also when changing lanes, when going over parts of the road that are not bad enough to cause that level of shock, and just randomly for no rhyme or reason that I can discern. Either way, I need to get the back end sorted out.

The scale of this job has increased a little. Now it is rear shocks and springs and front shocks as well. The front springs seem to be fine.

I need to collect some measurements and do some research, essentially, on how to lift and XJ, since I don't believe the Previous Owner (TM) did it correctly.

 

[Tim_MN]

A vibration that appears at about 50/55 mph, and disappears at about 60/70 mph, is most often a tire balance issue.

Clunking can be bad suspension bushings, rear sway bar bushings, or shock bushings. Worn u-joints may also clunk.

A clunk that can be felt is often a binding driveshaft slip yoke. A binding slip yoke is most often felt when starting from a dead stop.

 

[Long_Range]

Toss the blocks, buy Crown Up County replacement leaf packs and an Iron Rock full length AAL.

You will end up with 2+" of good riding, good load carrying suspension.

Crown and Dorman have the Up Country rear springs. Auto Zone carries the Dorman with a lifetime warranty.
Which is the better spring?

 

[Bilskirnir3124]

So, I got the measurements finally.

The center of the truck sits 17.5 inches above the ground, and both wheel arches sit 32.5" above the ground. My wheels are 29.1" in diameter (converting from metric, 235/75/R15). It seems that the Previous Owner (TM) also deleted the bumpstocks. Or they rotted out somehow. Not going to speculate on that. For my own sanity.

I presume that these are coil spring spacers, and they measure an inch in thickness (1 and 1/64 of an inch on my calipers).

Spoiler: Coil Spring Spacers?

Here's the rear leaf spring spacers. They measure at 2 inches, and the rear leaf springs are completely flat as you'll see in the second image.

Spoiler: Leaf Spring Spacers

Spoiler: Completely Collapsed Leaf Springs

All of this makes me think that the Previous Owner (TM) performed the lift after these rear springs had started to collapse given that the rear has more lift than the front, yet the vehicle rides level.

Anyhow, I need to figure out now how I'm going to get to a ride height of between 33"-34" at the wheel arches, or 18"-19" at the floor boards. I want to remove the spacers entirely and have proper height springs front and rear for the rid height I want. I'll also need to install some proper bump stops in the front and also do front and rear shocks to match the new spring rates. Does anyone have a good write up or a good video (series) to watch about how to do this sort of job? Extra tools I may need? I have a 1/2" torque wrench between 25ft-lb and 150 ft-lb, breaker bars for 1/4", 1/3", and 1/2" sockets, and I'm getting press (for bushings) and a torch. Anyone have any good question I'm not asking?