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rear spring flip

Discussion in '40- & 55-Series Tech' started by notaf-ingjeep, Feb 25, 2002.

  1. notaf-ingjeep

    notaf-ingjeep

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    has any one here fliped the rear stock fj40 springs around to gain the extra wheel base, it will make your pinion rotate diffrently as the suspension flexes will that cause any kind of negative effects.
     
  2. fecamel

    fecamel

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    Yes, I've done it. It makes axle wrap worse because the long part of the spring is in front of the axle. It probably wouldn't matter as much on a SUA rig than on a SOA rig, but a track bar is a good idea. The flexing doesn't cause a hugely different change in the pinion, just be sure your perches are in the right place and your pinion is either matched with the t-case (regular driveshaft), or pointed at it (CV driveshaft) when the rig is at rest. You will likely have to trim some of the rear quarters off to prevent the wheels from rubbing if you do this. It may cause aux gas tank clearance issues, and the shock mounts will have to be relocated. You might also need longer brake lines. You can flip the front springs to gain even more length.
     
  3. woody

    woody Internet Fireman Staff Member

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    IMO, the wrap bar is a must...I busted a pinion SUA once and SOA once, so I'm a believer. You gain 3.5" of wheelbase with a rear flip, and another 3.5" with the front flip. While yer in there, relocate your shackle hangers to get a better angle on those.
     
  4. FJ40JOHN

    FJ40JOHN

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    I knwo I am a little late on this...but....I did this recently on my SUA 40 with 4" springs and havent noticed any negative effects. I love the front end cuz of the killer approach angle I have. My bumper sticks about 4" past the front of my 36's. anythign i need to look out for when wheelin like this?? I knwo the SOA rigs have more trouble with the axle wrap.
    Thanks
    fj40john@yahoo.com
     
  5. woody

    woody Internet Fireman Staff Member

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    If your running aftermarket 4" springs, I wouldn't expect a wrap bar to be necessary. Those leaves are thicker and stiffer and much less likely to wrap than the thin stock leaves.
     
  6. bogdawg13

    bogdawg13

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    i flipped my rear and front springs also. i have the stock springs with a spring over. im running a big block so my spring wrap was horrible. trac bar fixed that problem. other than that all u gotta worry about is how much u like your sheet metal cause the rear fenders need to be cut if u wanna get flexy :D
     
  7. trastor

    trastor

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    hi
    i started puting on my fj40 a pair of fj62 spring, its fit on fj40 81+ (in venezuela) the only thing you have to do is turn the perch around so the longer spring fit property. with this set up you get about 3 inch in front and 3 more inch at the rear.

    sorry about my english, i am from south America :-[
     
  8. Slowerthanu

    Slowerthanu SILVER Star

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    What all will I have to watch out for if I flip the front springs (not wanting to do the rears until I SOA). I have a shackle reversal and Saginaw P/S already, what about shock mounts (I would figure the more forward position of the shocks would help with a shackle reversal? I dont think the steering will be a problem, but the driveshaft could present serious problems.
     
  9. GloNDark

    GloNDark

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    I ran both sets of springs reversed on my 69 FJ40. Other than SEVERE axle (Even with lift springs and a spring over) A trac bar for the rear is an absolute must. You WILL break pinions.

    But if you really want wheel base, put it on jackstands, cut all the mounts off and push it waaaaaaay out.

    103.5" is where it sits today. :D
     
  10. nuclearlemon

    nuclearlemon not an addict Moderator

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    i'm stock mounts, reversed front and rear, soa and i love it. but as everyone else has said, torque bar is mandatory. you've never experienced axle wrap until you've done it in this configuration with your clamps opened all the way.
     
  11. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    I ran the Rubicon with 32" tires, a shackle lift, sm420, lockers sag PS and bots sets of stock springs flipped. No track bar. I never noticed a problem. But apparently I am in the minority..
    [​IMG]

    It is a bit bigger now...
     
  12. trastor

    trastor

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    I reverse my front spring (fj60rear) and put a set of fj45 rear spring (rear) and its work pretty good. its doesnt need track bar (probably because Im using a 2f modify engine) :D
     
  13. Cracker

    Cracker

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    Dont forget that the coarse spline pinions are very susceptible to minor wrap. Broken pinions seem to be the most common breakage in LC 3rds.