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Cranking up the T-Bars

Discussion in 'Chevy Trucks' started by Hambrick & Co., Jan 9, 2008.

  1. Hambrick & Co.

    Hambrick & Co. PlowSite.com Addict
    Messages: 1,350

    I know this has probably been posted before but I want to tighten up the T-Bars on my 2005 Chevy Silverado 2500 HD 4X4. The front end is a little low when the plow is on and in the up/ travel position. How many turns do I turn the bolts? Are they the bolts on an angle underthe driver seat? Obviously I would do this with the plow off and then put the plow back on to test it correct? Any help would be greatly appreciated. Thanks Mike
     
  2. mikelawtown

    mikelawtown Senior Member
    from Mass
    Messages: 429

    1st jack up the front end to get the load off, then look under the floorboard/seat area for a long bolt with the head(3/4) facing down. (one on drivers and pass side) use a 3/4 wrench and turn clockwise 3-4 turns,(lube 1st) make sure u keep track of the turns and then in the spring just turn them back..Helps alot and is FREE..
     
  3. 06HD BOSS

    06HD BOSS 2000 Club Member
    Messages: 2,611

    Like mike said. jack up the front end, but i think the bolts are 15mm. i turned mine 4.5 turns
     
  4. Hambrick & Co.

    Hambrick & Co. PlowSite.com Addict
    Messages: 1,350

    Thanks for the help....
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Do not do anything until you take a few measurements.. measure the front and rear height at the body line right in front of the rear wheel well, and right behind the front wheel well. These 2 measurement will tell you how much lower the front is than the back AND most importantly it will give you a reference to return the truck back to the stock height if you ever decide to.

    Generally what you want to do is level the truck front to back BEFORE you attach the plow. Just getting it level will make it carry the plow fine..do not adjust the bars with the plow weight on the truck, it will make it too high once the plow is removed.

    After you have your measurements, jack the truck up until the front tire are off the ground, spray some lubricant of some type on the adjuster bolt threads and turn each bolt clockwise the exact same amount on both sides with an 18 MM socket..(make a note of how many full turns you turned them so you can also use this as a reference later if needed.

    Depending on how far the truck needs to come up in the front to make it level, I'd start with about 3 or 4 full turns and then take the truck for a quick spin around the block to resettle the suspension (important). Re measure it again and see where it's at.. if it needs to come up more, give it another turn or two.. don't be surprised if you need to go 6 to 8 turns or more to get it level as these trucks are pretty low in the front to begin with. Once you get it level, stop. Don't turn them anymore than it takes to get it level. This will give you the height you need without grossly changing the suspension geometry any more than needed.

    Torsion bar suspension isn't black science but to guys that don't understand it it can be.
     
  6. Hambrick & Co.

    Hambrick & Co. PlowSite.com Addict
    Messages: 1,350

    Thanks B&B
     
  7. PlowMan03

    PlowMan03 Senior Member
    from Maine
    Messages: 472

    After you mess with the torsion bars aren't you supposed to get an alignment right after wards so it don't chew up your front tires? Thats what I've been told a few times.
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    It depends on how much you actually need/want to raise the truck. So it's more of a "possibility" that a definite "yes"...but it never hurts to have one done regardless.

    An inch I wouldn't bother with it, anymore than that, yes I'd have it checked as it does affect the toe and camber after changing it a certain point.
     
  9. JD Dave

    JD Dave PlowSite Fanatic
    Messages: 11,045

    You should make a sticky about t-bars, you explain things very well.
     
  10. DeereGuy

    DeereGuy Senior Member
    Messages: 346

    gm notice/warning

    I was at the Fisher dealer having a plow install a week ago and asked about turning up the t-bars. He gave me a notice to read from
    GM about the possible braking of the shock and subsequent brake line damage: read, no brakes, big crunching noise when you hit that tree. I didn't do a search so maybe this is not news but I was a little surprised at the warnings.
     
  11. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Gm has been sending those out for years...they also include it in their up fitter manuals too.. The main reason they did it is from guys OVER adjusting the T-bars..

    These IFS trucks have a specific "working travel" and their is a spec to ensure it stays in this range (GM calls it the "Z-height") in the front suspension that is engineered into them (not total travel,"working travel"), and if it's exceeded can cause problems. As long as you don't get crazy with the adjustments their is nothing wrong with a T-bar adjustment. Why do you think they're designed with an adjustment capability in the first place?..Because not all trucks are used the same or or optioned exactly the same..and GM knows that some of these trucks will be outfitted with additional weight by the end user. So by designing the suspension to be adjustable, allows the capability to re-adjust the suspension back to "working travel" specs.
     
  12. DeereGuy

    DeereGuy Senior Member
    Messages: 346

    Thanks for the explaination B&B.
     
  13. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thanks JD... you might be right, this one and a good write up about duel battery installs would be perfect stickies in the Chevy forums...since they seem to be the biggest discussions in this forum.


    Glad the explination was helpful to you DeereGuy..
     
    Last edited: Jan 10, 2008
  14. saabman

    saabman Member
    from Maine
    Messages: 70

    As the risk of stating the obvious, added spring rate is what you need to handle a plow not additional static hight (T-Bar cranking). Any raising you do to handle to deflection of the truck with the plow will leave the truck nose "up" when undocked.

    Timbrens make the effective spring rate higher without raising the static ride height.

    The other option (pricey) is to get beefier tbars. The bigger diameter of the tbar is what gives it a higher rate.
     
  15. William B.

    William B. Senior Member
    from S.E. IA
    Messages: 978

  16. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Generally yes, the more weight you add, the more spring rate you'd want. But that doesn't totally apply to the T-bar suspensions on these trucks because a torsion bar suspension isn't as "liner" as a leaf or coil spring suspension. As long as the bars aren't too undersized for the job (most aren't if the truck was optioned correctly), you can imitate a higher spring rate without changing to a higher capacity bar on these GM trucks. And the way you do it is by raising the truck. When you raise these trucks, not only are you changing the static ride height, you are also changing the pivot point where the T-bar exerts it's twisting force in relation to the pivot point in the lower control arm. As you raise the truck, the C-arm is pivoted down and in, in relation to the mounting point on the frame (where the C-arm pivot point is) By doing this, your changing the mechanical advantage that the T-bar has on the ability to support it's load (the truck). Your basically creating a "fake" increase in the spring rate in the T-bars by making the job easier for T-bars to support the load.

    A simple and easy to understand example of this: If you get down on the floor to do push ups, are they easier to do with your hands right beside your body or are they easier with your hands 2 ft on each side? Of course they're easier the closer to your body they are...why? Because you moved the force closer to the load, not because your arms suddenly became stronger...well actually they did, but only because you moved the force closer to the load....same thing with the GM T-bar suspension. Has anyone noticed that guys find that after they installed a plow the truck drops a ton when the plow is lifted but after you turn the bars up to level the truck, the truck drops much less...why is that? You didn't physically change the spring rate of the bars, but by raising the truck, you changed the pivot point and thus the mechanical advantage that the bars have to help carry the weight. It's the same thing as moving your hands closer to you body in the push up example.



    Nothing wrong with running Timbrens..but a T-bar adjustment (not an over adjustment) should be done first..Some trucks aren't equipped with the correct T-bars for a plow application and in that case may not provide enough capacity to carry the additional weight, even with an adjustment (again with over adjusting them). So then yes, a set of Timbrems aren't a bad idea..
     
  17. Hambrick & Co.

    Hambrick & Co. PlowSite.com Addict
    Messages: 1,350

    OK so it sounds like half favor cranking up the T-bars and half don't go figure..... What is the diffrence between installing Tims and installing a Truxxx leveling kit. Would either one of those options definetly solve my problem? 2500 HD Plow Prep Package (2005)
     
  18. JD Dave

    JD Dave PlowSite Fanatic
    Messages: 11,045

    The trux leveling kit includes key and shock extenders, which what for you want won't do any better then stock. The timbrens are basically just a stop to keep your suspension from bottoming out. If you crank your stock keys a bit and add the timbrens, you'll be all set.
     
  19. Hambrick & Co.

    Hambrick & Co. PlowSite.com Addict
    Messages: 1,350

    OK so if I install the tims. which I can get at CPW do I need to do front and back?
     
  20. saabman

    saabman Member
    from Maine
    Messages: 70

    Just the front, they are passive until you load the front (and the plows weight is primarily borne by the front axle)