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Leaf Spring Question.

Discussion in 'Early CJ5 and CJ6 Tech' started by masscj2a, Jan 25, 2020.

  1. Jan 25, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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    I'm starting to work on my 70 CJ5 now, with a few days in the 40's, I've gotten a little enthused about getting work done. I've had a brand new set of Rancho, double military wrapped springs I bought for the Jalopy project, but decided to stay with the YJ springs on that one. The Rancho springs are supposed to be 2 1/2 inch of lift, but when laid on top of the stock springs, I see only 2 inch, but that's not under pressure. My question is this, I think they are going to be much stiffer than my saggy stock springs and that's to be expected, but could I remove the bottom most and shortest spring from the pack, without weakening the entire pack ? I'm also wondering if I need to ad a wedge under the perches in the rear. Prior to this and on more modern Jeep's, I would ad a wedge only around 4 inch spring lift, but not on 2-2 1/2 inch springs. But my drive shafts were longer on the newer Jeep's. I have not tightened the rear spring up yet or put the tires on the ground to check the angle yet. Figured I'd run it past you guys first.

    Have I ever told you guys how much I love taking apart old, original suspension parts ? Man it's the best thing ever, just love it...............
     
    Jrobz23 likes this.
  2. Jan 25, 2020
    Ns0mniac

    Ns0mniac Member

    San Clemente, CA
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    Aug 7, 2019
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    50
    If you shim the rear differential up make sure to shim the transfer case down the same amount to prevent vibrations and such.

    I wouldn't go taking the bottom leaf out, perhaps swap one of the leafs from your old saggy spring into the new lift spring? I'd try the lift springs out as they are right now first and see if they break in any, you might not mind them so much.

    Tom Woods has some great reading on his site regarding driveline angles, worth a read!
     
  3. Jan 26, 2020
    wheelie

    wheelie beeg dummy 2019 Sponsor

    York, PA
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    Mar 6, 2004
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    I would agree that the YJ springs would probably ride better but I have no beef with the Rancho lift on my 71. Rides good compared to the old Rough Country that was on it back in 1990.
     
  4. Jan 26, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I wouldn't do anything to the new springs other than install them and shim if necessary for driveshaft angle. You'll get used to them quickly, I did.
     
    Beach66Bum likes this.
  5. Jan 26, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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    Wheelie and Glenn, I heard that these were actually considered a pretty soft riding spring, hence my initial purchase. Usually what I do with new springs is ride around for a while on paved roads, without fully tightening the U bolts all the way. Then tighten them after a few hundred miles. I was told by old timers that was a way to allow the springs to fully stretch out to full length and allow a softer ride in the future.

    What length shocks or part number shock did you end up going with? I have almost 22 inches now at full drop from center of shock stud to stud.

    Also, did you go gas charged or plain oil filled on the shocks ?
     
    Ns0mniac likes this.
  6. Jan 26, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I don't recall using special shocks or different length shocks. Everything I bought was in a kit. As far as tightening the u-bolts I fully tightened them to begin with. Of course re-checking them for tightness after a few miles is a good idea. Not originally fully tightening them doesn't sound like a good idea to me, how does one determine what "not" fully tightened is?
     
    masscj2a and 45es like this.
  7. Jan 26, 2020
    sterlclan

    sterlclan Member

    exploring the...
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    i prefer old school oil shocks, seems less abusive on the mounts.
     
    masscj2a and Glenn like this.
  8. Jan 26, 2020
    Lockman

    Lockman My " Rosie" 2020 Sponsor 2019 Sponsor

    White City, NY 14617
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    A Cutting Torch makes it more Fun........ & Warmer :)
     
    Hônes likes this.
  9. Jan 26, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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    I was thinking the same thing and less rebound.
     
  10. Jan 26, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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    So obviously you have been to my barn. It's a hay barn, so if your not on top of the torpedo, you ain't warm.
     
  11. Jan 26, 2020
    wheelie

    wheelie beeg dummy 2019 Sponsor

    York, PA
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    Oil shocks for me on everything I own. Of course, the newest thing I own is 1999 soo.........

    I'd have to look for the Rancho PN for the shocks but I recall wishing I had a bit more down travel from them anyway. I think they limit my suspension movement and that's bad. Shocks should not be limiting factor. Bad for them.
     
    masscj2a likes this.
  12. Jan 26, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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  13. Jan 26, 2020
    duffer

    duffer Rodent Power 2019 Sponsor

    Bozeman, MT
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    I'm not sure which of my FSM's had torque specs for U-bolts based on their diameter but I think it was my 74 version. I torqued by 1/2" versions to 80 ft lbs and will probably re-torque them every 100 miles or so until there isn't any noticeable change.
     
    Glenn likes this.
  14. Jan 26, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sounds like a good plan to me!
     
  15. Jan 27, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    FYI the OME 2 1/2 inch rear springs for a YJ come with a 2 degree wedge already installed. Check your springs to make sure there's not one already there.

    I'm very partial to Rancho 90000 series shocks. One of the magazines did a big test a few years ago with a bunch of the name brand shocks in the $100-150 dollar range, and the Ranchos won.

    Field Tested:Rancho RS9000XL - Expedition Portal


    Mike
     
  16. Jan 27, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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    Mike I only mentioned the YJ springs as staying in my 46 project. I'm using new Rancho cj5 springs in this 70 cj5. Sorry for any confusion.

    I'm not sure which degree of shims I should use in the rears. I'm thinking between 2-4 degrees. I'll have to get the longer spring bolts as well.
     
    BadGoat likes this.
  17. Jan 27, 2020
    masscj2a

    masscj2a Member 2020 Sponsor 2019 Sponsor

    Chester Mass
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  18. Jan 27, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    Here are the shocks that Rancho recommends for their 2.5 inch springs. Looks like it's the same 4 shocks for each corner. 5xxx 55xxx 7xxxx and 9xxxx are just different series of shocks (e.g. 5000 series vs 9000 series).


    Mike
     
  19. Jan 30, 2020
    70cj5134f

    70cj5134f Member

    East Tn
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    Aug 18, 2018
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    I've got RC, 2in lift, YJ springs on my 70, with the bottom spring removed!
    I did cut a piece out of old spring to use as a space fill under axle.
    I also turned the spring upside down, parked a diesel pickup on top , over night
    To dearch spring a tad. Rides like an ATV!
     
  20. Feb 28, 2020
    Hônes

    Hônes New Member

    Colorado Springs CO
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    I say experiment with any combo of springs by taking out a leaf and testing how YOU like it.

    With 4” Superlift “SuperRide” springs years ago, (5 leaves per pack) I kept them like that until going SOA which then gave more lift than needed. I experimented pulling 1-2 of the shorter intermediate leaves out to flatten the pack out some but not the two longest ones. Ride was even better IMO and it softened up the pack nicely for more axle travel. I further increased their flex capabilities by heating and prying the spring clamps to be open on the top to let the leafs fan out vertically during suspension droop but not laterally. (see attached picture showing the supporting leaves pulled away from the main)

    Without the double military wrap that you mention is on yours, this does place additional stress on the main leaf. BUT, just like running soft rubber tires for off road traction, my #1 goal was off road capability not necessarily longevity of tire tread and spring life.

    I found basic hydro shocks to do all I needed for the relatively slow speed life of my CJ between crawling and top speed of 55 mph in OD. Those nice nitro-charged units were great for my higher-speed capable rigs for sure that saw air-time and sand dune running. ProComp used to sell (and maybe still does) ES1000 basic shocks and could be ordered in sizes up-to 36” fully extended with the eyelet mount style and with all those fun accordion boots if you like those.

    In rock crawling, I found that more expensive shocks RS9000, ES9000, etc found sharp rocks to tenderize themselves on the same as cheaper ones. After bleeding several out, I started just going with the cheaper units. I learned at the same time that moving shocks up out of the rocks by mounting them higher on axle tubes instead of on the u-bolt tie plate was good if a higher upper mount was feasible. This also permits turning the mounting bolt to be parallel to the frame rails to prevent bushing bind IF you've got a lot of articulation in your setup. It just depends on whether your shock needs to lean more side to side versus front to back. Mine needed side to side more and thus benefited from re-orienting the axle-side pivot bolt.

    My recommendation for shock length testing is:
    1) Do the lift you want first. (You get to drive around temporarily without shocks. It's fun I promise) Find a ditch to park diagonally over so that the body/frame is level to the horizon but the suspension is maxed out and preferably one drooped side is hanging in the air. You DID freshen up those limited slip clutch plates before this, right?
    2) Slide under in your Sunday best with tape measure in-hand and find out what your ACTUAL compressed and extended lengths need to be.
    3) Order shocks that won’t become your limiting strap nor a bump stop (leave that for your brake lines!! see picture below lol) If you can’t find one that does both, consider having your shock mounts moved farther apart. I built a 30° index ramp for comparative (quantitative) testing of suspension setups and combinations but for real world max/min shock travel, a nice drainage ditch was best.
    -Hônes
     
    Last edited: Feb 28, 2020
    txtoller likes this.

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