1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Rear Leaf questions

Discussion in '40- & 55-Series Tech' started by bad_religion_au, May 10, 2003.

  1. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    would a 60 series rear leaf spring, to fj40 rear be a huge job?, do things like the pins line up (whatever you call that bit where the axle is bolted to the spring) or do i have to move spring hangers to keep drive train stock length? a friend of mine suggested this instead of getting the springs reset as 60 springs are cheaper
     
  2. Guest

    Guest Guest

    All I know is that the rear Dampers from a HJ60 fit on the rear of a BJ40.
     
  3. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    well, i've researched it a bit, and it looks like it may move the axle back about 2 inches, maybe slightly more. is this fine for stock 4sp drivetrain, or will my driveshaft come apart.

    i'd move the spring hanger forward, but i don't trust my welds well enough, and it is my daily driver.

    or could i just hook up a 3sp driveshaft (2inches longer) and get away with it?
     
  4. LT

    LT

    Messages:
    1,783
    Likes Received:
    26
    Joined:
    Apr 8, 2002
    Location:
    Portland, OR
    The front springs are the same length and the rear springs are about he same size as a rear pack from a FJ55 except they are off center. You would have to get bigger bushings and a bigger center pin as well.
     
  5. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    it will move your axle back, will require driveshaft lengthening, will require work to relocate the shackle hanger, will require some "adjusting" of the solid mount to squeeze in the larger diameter spring eye of the 60 packs, will require custom shock mounts, and more.

    That said, it's a great swap, since the longer springs increase your travel potential.

    "huge" is in the eye of the beholder (said as I begin modification of a spring pack for a 1/4 elliptical 4-link suspension.....)
     
  6. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    true, but as a relative newbie to machinery, ummm this has potential to be big.

    ok so if i butcher the solid hangers off, any tips on connecting them back up so my rear solid hangers don't just fall off due to problems in connecting them, like what is the best way to weld them.

    is the fj55 rear spring swap as "intense". will they fit the fj40's bushings etc.

    or should i just basically get the springs and both hangers/ shackle mounts etc, be brave, cut the rear hangers off and bolt (can you do that, prob better than my welds atm) or weld the 60 hangers on, a few inches forward to keep stock driveshaft, and the rear ones a bit back for shackle angle, or alternatively keep the rear shackle hanger in the same place and use a sicsor (spelling !!!) shackle, with the top one extending backwards flat (or almost) and a second hanging down like normal.  maybe secure the top shackle with a pin or something for on road driving (less sway due to less suspension component movement)  then offroad remove the retaining pin,  and voalla more rear travel.

    any and all flaws in there can be critisised, i'd appreciate the feedback.  as i've said many a time, i'm not much of a fabricator, little welding skills, no welder (can use friends though).  and this is my baby (and daily driver) so it probably can't be off the road for much longer than a weekend, so time constraints.....  and needs to be very driveable and reliable.


    ohh almost forgot.  if  i mod it enough to keep stock axle possition, can i get away with stock shock mounts. and stock driveshaft... would the 3 speed shaft work as an extended shaft? if i did the swap properly, and lined up the rear axle to stock position, would it be ok to keep stock driveshaft, or would it still need to be longer (to cope with lift/ more travel) if so, is my 3sp driveshaft idea bad, or ok, i'm trying to keep prices down

    also would i use 40 Ubolts, or 60 Ubolts. is there an easy way to flip them while their off? would this swap affect the shock mounting on the U bolt plate thingy (told you i was a newbie

    one other question, not as important, but in the distant future (when i get money, and maybe a daily driver) would the 60 rear springs be ok sprung over, or would they be too big

    sorry for all the questions, but as i'm on a tight budget, i want to get it right 1st time and make it completely road driveable (i cover 700Km or 420 miles) a weekend. thanks woody and you guys.
     
  7. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    hhhhmmm....let's see if I cover all the answers or not....

    -Yes, it can be done in a weekend.
    -40/60 u-bolts are the same...might need slightly longer since I'm guessing the 60 packs are slightly thicker
    -55 rear packs have a slightly smaller spring eye and do work in stock 40 solid hangers, BUT they will definitely move yer wheelbase 3.5" back.
    -u-bolt flip kits are a different animal entirely....IMO, use one of the many kits out there for this.
    -bushings are different regardless, and that's one "detail" that could cause issues....would want them in hand. see SOR.com, search for "poly"
    -I would not weld on hangers, but would re-bolt on with grade 5's
    -if you retain the stock axle location, no need to adjust the driveshaft
    -remember if you do run longer packs and reposition the stock hangers to retain the stock axle position, the hanger is lower on the frame and that = lifted slightly....might require shock change too, plus the longer/flexier springs might require it anyways.

    do you want the longer wheelbase or not?

    IMO, this is a definite day-only project, but you gotta be prepared...not prepared with all stuff can add a week in order time quick....
     
  8. tetradymite

    tetradymite

    Messages:
    18
    Likes Received:
    0
    Joined:
    Feb 25, 2003
    Sorry to jump in:

    Woody,

    Question about the grade five bolts on the spring hanger. Are they strong enough, or is grade 8 considered to brittle?
     
  9. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    honestly, I don't think there are enuf issues on the grade5 versus grade8 discussion to care....the general rule is, grade 5 for shear, grade 8 for tension. You'll find arguements for and against that all over....

    If these were airplanes, I'd worry. They aren't, mine contains a mismash of whatever the hardware store had handy in the size I needed, and I've yet to have any problems.

    (someone will post up with something technical and informative, but I still don't think it matters for our "light duty" situations)
     
  10. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    thanks. i'm not after extra wheelbase.

    so i don't have to weld really, just drill and bolt.

    i'd definately get all my stuff together 1st.

    i've seen pics of people positioning the moved solid hangers to the outside of the frame, to keep them up out of the way. i gather this requires fab work, or do they bolt them on sideways (poor explanation i know), but it sounds easy enough to just put them on the flat position on the chassis.

    if i was to go ahead, and used the existing shock, it'd still be driveable, and the shorter shock would just limit articulation wouldn't it. i'm just thinking it's easier to do this then outlay fat wads of $$$ for the shocks as well, guilt sets in if i spend more on my car than on food for 2 months.

    how about the siscor shackles in the back, bad idea or doable. respect you guys opinions heaps.

    should i just get the spring and the hangers of the 60 and work from there.
     
  11. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    get the springs and hangers, go from there.

    I'm not a fan of folding/scissors shackles....they do add articulation and are great for some areas, especially if you do a lot of "flattish" boulder crawling. They are marginal on steep uphills and IMO dangerous on steep downhills (tend to unload) But it does depend on your primary wheeling terrain.
     
  12. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    never thought of them downhill,, wow  :eek: that could have been a surprise.  might let my mate in the 75 try that one first.

    will i need 60 series shackle hangers, or can my 40 ones suffice. and take the 60 series shackle of course (being wider and all)

    shame, my rear shackles are awesome, their completely boxed, and don't invert at all...

    i'm guessing poly bushings are the way to go, although i've read bad things about poly lately...
     
  13. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    one last question for this conversion. from what i have seen, the 60's seem to have a short flat overload leaf. would the back of the 40 (with roof, and occasionally 2 rear passengers) be heavy enough to warrant the overload leaf, or should i ditch it straight away.
     
  14. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    I run all 8 leaves on my FJ55 rear packs in the back of my FJ40...plenty soft, no top, no rear passengers. I run all 8 factory leaves plus one additional leaf in front, even with the lighter V8 motor.

    IMO, it will limit up-travel a bit, but might be needed to keep some load carrying. Could go either way...it's an easy install/pull if you change your mind tho!

    I'd start with it in and see how it flexes/rides/carries, then decide. Removing right away and flexing up might flatten the rear packs prematurely and that creates other issues.
     
  15. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    thanks for that.

    i'll leave it in then. see how it goes. i suppose with stock fenders, the limit in upwards travel may stop the tyres from beating their own guards.

    this is getting crazy, each idea, or problem solved adds a new idea, crazier than the last.

    would adding 60 series rear springs in the front sua, using a similar method to my rear springs, moving the hanger back etc. alter the steering geometry and the such. or would it be streetable and alright to drive around, or safer keeping it stock.

    this is turning into an out of control fantasy.....

    watch it, as soon as the hj45 is back on the road, it'l be time for the fj to get all this stuff done.... my bro will kill me
     
  16. woody

    woody Internet Fireman Staff Member

    Messages:
    10,334
    Media:
    303
    Likes Received:
    1,089
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    lol....get the rears done first...then worry about the fronts!
     
  17. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
     :slap:   thanks, i needed that slap back to earth.  get hj back on road, fix it's transfer case (hopefully) then the rears, then rollbar, then do the front, by which time more problems will rear their ugly heads..... getting ahead of myself here

    p.s. if your in melbourne, and the rear springs of your 60 dissapear, i swear it wasn't me :D

    woody if i'm ever in USA, or you ever come down here i'm buyin you a  :beer:
     
  18. Guest

    Guest Guest

    If you're in Melbourne, And the rear Springs of your HJ45 dissapear, i swear it wasn't me :G
     
  19. bad_religion_au

    bad_religion_au

    Messages:
    2,212
    Likes Received:
    0
    Joined:
    Apr 24, 2003
    you want hj45 springs? why???

    their too stiff in my opinion
     
  20. Eskimo

    Eskimo SILVER Star

    Messages:
    1,358
    Likes Received:
    0
    Joined:
    Sep 6, 2002
    Location:
    Danville, PA
    BTW, a grade 8 is stronger than a grade 5 in all aspects...shear and tension. The whole "grade 8 is brittle" thing is folklore.