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'08 rear suspension

Discussion in '2nd Gen. Tacomas (2005-2015)' started by BLOCKADE, Feb 22, 2008.

  1. Feb 22, 2008 at 7:12 PM
    #1
    BLOCKADE

    BLOCKADE [OP] Well-Known Member

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    I have been wondering for the last few weeks whether or not my '08 TRD Prerunner needed the rear leaf TSB. Today was the first time I really had enough weight in the bed to really test out the suspension and from what I could tell, even though it is only a three leaf set up, I had no bottoming out. I have tried to find out if they beefed up the metal by making it with a more rigid alloy but haven't been able to find any information. The part numbers are slightly different (the '08 ends with a F) so this could be the case. It really doesn't make much sense to me to just leave that 'flaw' in the newer model year.

    Any body have any thoughts on this?
     
  2. Feb 22, 2008 at 7:27 PM
    #2
    lsocoee

    lsocoee My hair is all natural Staff Member

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    Did you check out your clearance between the bumpstops and the frame?

    How much weight did you have back there?

    I think that once your suspension breaks in, you'll suffer from it more. The bottoming out isn't too harsh, so you might not notice it.

    Toyota might only need to replace 40% of the springs. If they have a bunch left over, they'll probably finish using them and then change the design. The stock springs are more comfortable than the newer ones. Many people prefer a softer ride than a larger capacity.
     
  3. Feb 22, 2008 at 7:39 PM
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    BLOCKADE

    BLOCKADE [OP] Well-Known Member

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    I don't know exact weight, it was a front end loader full of topsoil. I've had 200lbs in there before and this was definitely over 400. I will take pictures tomorrow, I have to go back and get a second load. I'll also check the clearance.

    You could be right though about the newness and time making a difference. I'll keep you posted.
     
  4. Feb 22, 2008 at 7:59 PM
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    lsocoee

    lsocoee My hair is all natural Staff Member

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    It really depends on the front end loader and the soil dryness. Before my tacoma, I rented a Silverado to get some sand to my house. I had him put one bucket in and then I decided that it was a rental and he should add another bucket to it. I calculated it out; the sand, which has a density greater than top soil, ended up weighing 1000 lbs per bucket.
     
  5. Feb 22, 2008 at 9:39 PM
    #5
    kjnkidd

    kjnkidd Member

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    I'm glad you posted that. I've been reading all of these post sitting here thinking I would have to have work done on my 4 day old truck.

    The most I ever carry is maybe a transmission, light lumber or a couple of gas cylinders. No towing.

    I think I'll stick with the softer ride.
     
  6. Feb 23, 2008 at 8:56 AM
    #6
    klown

    klown Tacoma World Ring Leader

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    Yeah, toyota corporate tells me the rear leaf springs have been redesigned to address the TSB. I tried to get the TSB but was told by toyota corporate that the TSB wasn't applicable to 2008 models. The issue was apparently addressed with a newly redesigned rear leaf spring. I hope this is the truth, cause I like the stance of my truck as it is, I don't really want the rear end to be raised up due to the fourth leaf spring. I'm glad you've given your account with about 400lbs of stuff in the back. When I load my bed up I will check the ride also, but at this point it doesn't look like it's an issue for 2008 model years.
     
  7. Feb 23, 2008 at 9:44 AM
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    Zebra

    Zebra Well-Known Member

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    i loaded my 08 up with 20 cases of bottled water from sam's club the other day and no bottoming out.
     
  8. Feb 23, 2008 at 10:21 AM
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    Mellow

    Mellow Well-Known Member

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    Just picked up mine 2 days ago, loaded it with 8 bags of quickcrete (400lbs) and about 10 landscape timbers and a few other boards. I couldn't tell any difference in ride and no noticeable difference in the bed height however, I'm sure there was at least a little.

    I don't know what part numbers to look at so let me know and I'll go check, maybe it doesn't matter if they redesigned the part?
     
  9. Feb 23, 2008 at 12:14 PM
    #9
    JTDTacoma

    JTDTacoma Well-Known Member

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    I loaded my 08 up with firewood (a heaping pile) expecting it to be draggin ass after all the complaints. It wasn't close to bottoming out with the 3 leafs. I hope they addressed the issue!
     
  10. Feb 23, 2008 at 2:57 PM
    #10
    klown

    klown Tacoma World Ring Leader

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    Looks like you guys don't have an issue, from what I can tell, before 2008 these types of loads would have caused you to bottom out.
     
  11. Feb 23, 2008 at 3:30 PM
    #11
    concrete jedi

    concrete jedi Well-Known Member

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    My 06 doesn't have an issue with only three leafs, lucky I guess.
     
  12. Feb 23, 2008 at 3:52 PM
    #12
    BLOCKADE

    BLOCKADE [OP] Well-Known Member

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    I went back today and got quite a lot more dirt so I was not able to get an accurate measurement (this time it was definitely bottoming out, I had 800+ lbs) . I'll be building a fence in the next couple of weeks and check the measurements then. But it does sound like they may be a bit more sturdy.

    All that would have been necessiary for the three leaf setup to work is to just use a more rigid pieces of steel (just change the alloy chemistry a bit by adding more carbon). I bet they are stronger, just not as strong as the four leaf set up.
     
  13. Feb 23, 2008 at 6:37 PM
    #13
    Zebra

    Zebra Well-Known Member

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    from what i've seen they redo the shocks as well. that may play a role as well as the leaf springs
     
  14. Feb 23, 2008 at 9:26 PM
    #14
    TacoTurd

    TacoTurd Defying Alliances since 2007

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    That's wrong. The modulus of iron or steel doesn't change with carbon content (or hardness or anything else I can think of).
     
  15. Feb 23, 2008 at 10:35 PM
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    lsocoee

    lsocoee My hair is all natural Staff Member

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    I thought, what the hell happened to TurdTaco? Then I realized that you are actually TacoTurd, dropping some knowledge.

    Adding carbon to steel increases the hardness and strength.
     
  16. Feb 24, 2008 at 8:44 AM
    #16
    TacoTurd

    TacoTurd Defying Alliances since 2007

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    Up to a point adding carbon increases hardenability of steel (by heating and quenching). Hardness IS strength, just measured in a different way.

    But NOTHING changes the stiffness (young's modulus). It will be 30 x 10^6 psi no matter what. If the 08 springs are dimensionally the same as 05-07 (I think they are), then the spring rate HAS to be identical.

    Gotta go spin the propeller on my beanie now.... :eek:
     
  17. Feb 24, 2008 at 9:10 AM
    #17
    lsocoee

    lsocoee My hair is all natural Staff Member

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    It can be anywhere between 28 and 31, so there are some options there.
     
  18. Feb 24, 2008 at 9:46 AM
    #18
    TacoTurd

    TacoTurd Defying Alliances since 2007

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    Not as a function of carbon content.

    My point is nobody is alloying steel to change the section modulus of a Toyota leaf spring. It's a silly notion. I'm all about silliness, but not when it comes to metallurgy.

    The section modulus of a leaf spring will be directly proportional to the material modulus and the width, but the cube of the THICKNESS. Guess which knob it makes sense to twist.

    OK OK I'm going back to the MPG threads now... :)
     
  19. Feb 24, 2008 at 12:31 PM
    #19
    BLOCKADE

    BLOCKADE [OP] Well-Known Member

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    I'm not sure if tacoturd is correct or not, but, it sounds like he knows what he is talking about... so I'll agree with him. Maybe they are thicker pieces of metal?

    (any time you start throwing numbers and fancy formula at me... you automatically win.:eek:)
     
  20. Feb 24, 2008 at 1:41 PM
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    lsocoee

    lsocoee My hair is all natural Staff Member

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    :lalala:
     
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