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Leaf Spring Replacement

Discussion in 'Daihatsu Hi jet' started by superhijet, Jul 10, 2008.

  1. superhijet

    superhijet Member

    just an idea to get rid of leaf springs to use air bags
    would weldin box steel legs with support brace onto the axel work?
    so that it becomes a swining arm
    then fit brackets and airbags
    comments please or other ideas
  2. Mighty Milt

    Mighty Milt Active Member

    take a look at that site i sent you for air ride, they have a system like that for 3/4 ton trucks i think. the key would be to use good thick walled tubing, fish plates and gussets to make sure it's going to hold together.

    it's not a bad system, it's just limiting if you are looking for a lot of travel. to get travel you really need to step it up to a 4-link system... but it you are just looking for low with a decent ride quality then you can do it like that with no problem.

    i would do your c-notch or step notch first, then take lots of measurements and pictures. try to lay out the "swing arm" against the springs to make sure your geometry stays the same. you will also have to factor in some "wedge" to keep you pinion angle correct once it's been lowered. no wedge = bad vibrations and premature wear on the 3rd member.
  3. superhijet

    superhijet Member

    heres my idea

    Attached Files:

  4. superhijet

    superhijet Member

    i may have to c-notch the frame aswell
    im just looking to close the 8" gap i have between body and rim
  5. Mighty Milt

    Mighty Milt Active Member

    i don't think i would feel comfortable welding to the axle house to be honest. i would find a way to use mechanical fasteners instead. it will also be easier to adjust for any inconsistencies in alignment and any replacement later on down the road.
  6. superhijet

    superhijet Member

    why wouldnt you weld to the axel?
  7. Mighty Milt

    Mighty Milt Active Member

    I wouldn't weld to the AXLE because you take a chance at warping the axle tube and damaging it, not to mention you have no adjustment for alignment of all 4 wheels. you would have to use (in my opinion) at least 1/4" walled tubing and the heat saturation when welding that can do a lot of damage.

    even if you decide to weld to the axle you will have to have at least a "3-Link" set up, some sort of sway control from the side of the frame to the rear axle.

    go to this link, it's installation instructions for a kit they sell that does exactly what you are looking to do, it's all mechanical fasteners, no welding and some decent pix for you to get an idea.

  8. superhijet

    superhijet Member

    man, you are like the advice guru
    that page has rested my mind on a lot of issues
    i can now sleep (maybe)
    ill do another diagram to see what i can make
    (i can visualise it now but i like to put draw it so it makes more sense, if you know what i mean)
  9. Mighty Milt

    Mighty Milt Active Member

    thanks, just glad to help.

    you can always add to my reputation power if you like ;)
  10. superhijet

    superhijet Member

    some thing like this?

    Attached Files:

  11. Mighty Milt

    Mighty Milt Active Member

    much better, now you just have to see how that jives with the frame, and remember keep the airbags behind the axle!! otherwise there is too much unsprung weight and it will work more like a fulcrum than an airbag and will bend your trailing arms.
  12. superhijet

    superhijet Member

    id like to get all the components before i start
    i cant afford an air kit so ill source the bits individualy
    when the air is in the system how is it let out?
    i know how a compressor works and obviously turning it on will fill the bags but not sure how they empty
    i know i dnt have to have a tank as i could have the van rise when i start it up by fitting sensors but its better to
    ill need to know the ins and outs if im mixing and matching bits
    i have my eye on a used range rover p38 compressor, new lines and connectors
    not sure on the size of bags ill need at the moment, could i use range rover ones? or will the be too big?
  13. Mighty Milt

    Mighty Milt Active Member

    a couple different ways to do it...

    down and dirty...
    compressor with a check valve that goes to a gauge and switches in the cab... the line goes from the gauge to a TEE and then a line to each back wheel. inside the cab where the gauge is there is one switch is for power to the compressor the other is a mechanical "dump" for the air.

    i don't like it this way for a couple reasons. the first is that i don't like the smelly air that comes out of bags, and i don't like the sound of the air in the cab either. the second thing i don't like about this system is having one line tee off to both wheels. this perpetuates "body roll" in curves.

    when making a right turn all the weight shifts to the left, when you have a common line it allows the left bag to compress there by inflating the right and will make the truck feel like it wants to flip.

    the way i prefer to do it...

    air ride has a nice one called load controller II or something like that... it was about $150 or so the last time i bought it.

    it's a little digital box that mounts in the cab, it's about the size of a trailer brake controller and has a digital read out. it controls the the air bags separately. one control for left and one for right, eliminating body roll problems. once you have the pressure set any increase in weight will be compensated for. but you can also fill and dump manually if you chose. i had the compresser, check valves and dumps mounted under the bed of my truck. i like to run a tank so it will inflate faster. just a small one gallon is usually enough. otherwise you have to sit there and hold the button for what feels like forever while that tiny little pump slaves away.

    i would look into getting the little "beer can" bags... http://www.airliftcompany.com/ride_control.html i had them and they worked great, they will compensate for about 2000lbs i think and they come with all the brackets and lines. they were about $200 if i remember correctly and would be perfect for a truck as small as the minis.

    for prices you can check on http://www.summitracing.com that's where i got a lot of mine

    check out the air lift site i've refrenced for more than just the page i referenced, i learned a lot reading up on there.
    Last edited: Jul 10, 2008
  14. superhijet

    superhijet Member

    top sites with top info
    thanx for that
  15. superhijet

    superhijet Member

    i know where im going with this
    im going to make a 3 link set up
    i think there is enough room under there with the propane tank
    when using airbags i dont need shocks do i?
    if not, im going to make a rod/solid bar (adjustable tie rods) 3 link set up
    ill hopefully use the shock mounts on the axle for the rods
  16. Mighty Milt

    Mighty Milt Active Member

    you are going to need shocks, absolutely
  17. superhijet

    superhijet Member

    ok thanx
    when looking around the web some have fitted bags without shocks on the rear not even the ones within the airbag
    it does make sense to have them though
    with each end of the tie bar is it better to fit rose joints or bushes?
  18. greg0187

    greg0187 Moderator Staff Member

    Came across this looking for something else, and then it reminded me of this thread. Rear suspension of a HiJet Van. I believe this is what you are wanting to achieve. Enjoy.


  19. mitsu911

    mitsu911 Member

    Hauling wood with lift

    The rear springs don't seem to hold much weight, would like to put airbags between the frame and axle tube. Does anyone that knows something about these have any suggestions?
  20. mitsu911

    mitsu911 Member

    Wood hauling

    Right now I have leaf springs in the rear
  21. cajun666

    cajun666 New Member

    my hijet have no problem handling a ton with stock shocks
  22. Socal Sonny

    Socal Sonny Member

    Nice find Greg! that rear setup with some coilovers would be perfect..

    Has anybody found a company that has stiffer leaf springs for our Hijet??

    Heres a picture of some guy in a japan who added an extra shock to stiffen up his Suzuki Carry

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