Lowering blocks

[ocnblu]

Yes sirs, my new truck is in. 2007 Sierra regular cab shortbed 2WD. It's a goodlooking truck, to be certain, however, the rear end sits a bit too high for me, it has a definite rake. Lowering blocks seem to be a simple solution. Question for anyone who knows: If my truck has progressive rate springs, that means the more pressure that is put on them, the harder they'll ride, correct? Do lowering blocks compress the springs? Can I install a set of 2" lowering blocks to level the ride height of my truck without affecting the ride? Sorry to sound like a dummy, but this is out of my line of experience. Thanks in advance!

[Intrepidation]

I think it gives it a stance, which looks good.

[balthazar]

Lowering blocks on a leaf-spring vehicle should install between the axle and the spring pack (assuming the spring mount below the axle tubes). The axle would remain in the same position of course, but the springs (& frame & body) would now be lower. This would not effect the spring compression (the arch would remain the same), just the relative position of the 2 to each other. Ride would be unchanged.

Lower away!

[ocnblu]

Thanks, balthy. I trust your judgment. I surfed for some info after I posted this thread. What I'm after is a level stance, I don't want to drag my butt. I am thinking of 2" steel blocks. I understand due to the geometry involved, a 2" block will actually bring the bumper down more than 2" back there. I'll have to do some measuring, I guess.

[balthazar]

Is that true: the spring pack is on top of the axle tube on the '07s? Just seems weird to me- wouldn't that limit travel/suspension compression that much more? Doesn't seem logical, but I've not stuck my head under a GMT900....

[76ChevyTrucker]

Well, for the past.....30-ish years all GM full-sizers have had a 2-inch higher ass than their nose. My truck sits that way, personally I like it, but if you're looking to level, two inches should drop the truck level.

[capriceman]

Quite Simple

Step 1: Buy several 50lb. bags of sand.

Step 2: Add 50lb. bags in the bed until desired height.

Edited January 18, 2007 by capriceman

[76ChevyTrucker]

Yeah, you could always do like caprice said, and gain traction in the process!

[ocnblu]

That's a good idea to see how it looks with a level attitude, then measure for a more permanent solution. Edited January 18, 2007 by ocnblu

[ocnblu]

Hmmm... I spoke to a friend of a friend today. He has an '02 Silvy same bodystyle as I'm getting... he says blocks will not work on a GM fullsize truck, he had to change his rear spring shackles to bring his truck to level.

[balthazar]

'blu- can you get us a pic of the axle/perch/spring area on your truck- I'm still curious about the specific set-up.

[ocnblu]

Sure balthy... I'll be picking it up tomorrow morning. As long as the weather is decent (it doesn't look encouraging), I'll be posting some pictures.

[76ChevyTrucker]

I'm with Balth, if its a traditional leaf spring set up on your truck, you should be able to block it without changing the shackles, now if you wanted to actually LOWER the truck, not just level it, yeah you'd have to reshackle it.

[Sixty8panther]

An ass 2" too high when empty means your truck will not be

draggin' its Captin's Quarters when under a decent load.

[ocnblu]

Here's a picture of my spring setup:

[balthazar]

Yeah- you're left with different shackles (if available) or new, lower-arch springs as options (assuming sand bags is out). I put new springs in my F-150 when one side broke; bring it over.

[76ChevyTrucker]

Asside from reshackling it you could try, and I do mean try, putting the block between teh bottom of the axle and the plate, I've seen some people do it that way, so you'd be bringing the axle up under the truck some, thereby lowering it.

[ocnblu]

There is a 2" shackle kit for the new style trucks available already, I think the company is called DJM Suspension. And the top of the rear bumper is exactly 2" higher than the top of the front bumper. I think this is gonna be my first mod. Edited January 21, 2007 by ocnblu

[balthazar]

Asside from reshackling it you could try, and I do mean try, putting the block between teh bottom of the axle and the plate, I've seen some people do it that way, so you'd be bringing the axle up under the truck some, thereby lowering it.

Take another look at the pic, 76: that's not going to do anything but lower the plate. The distance between the axle and the body (more specifically: the spring hangers) will remain the same. The axle's position cannot change; the tires are on the ground- you have to move the spring's height either where it contacts the axle or where it anchors to the body (hangers).

[rkmdogs]

Hmmm... I spoke to a friend of a friend today. He has an '02 Silvy same bodystyle as I'm getting... he says blocks will not work on a GM fullsize truck, he had to change his rear spring shackles to bring his truck to level.

Tell your friend to look again!

Yes, blocks will work on any leaf-sprung truck however.......

He was correct in telling you that you will have to get new, longer shackles, which are the U-bolts that go over the top of the axle

and down thru the spring perch mounting plate. Since you will be increasing this distance with the addition of the lowering blocks,

you need to add that amount to the length of the U-bolts that you will need. If you buy a lowering kit, they usually include the

longer bolts with the lowering blocks.

Most leaf-sprung trucks from the factory mount the springs under the axle. The bit about mounting the OVER the axle is

a conversion done by the off-roaders for more clearance for bigger tires.

Go to a bookstore and look in a Chiltons manual. It should have a picture to show you the set-up.

[balthazar]

The axle's height will never change (barring flats, different height tires, or a floor jack).

'Blocks' fit between the spring pack & the axle tube. If the spring pack goes under the axle tube, adding blocks between will push the spring pack lower, in turn lowering the body. But if the spring pack is above the axle tube, adding blocks between will raise the spring... and the body. In order for blocks to alter the height, they must go between the spring pack & the axle tube - placed outside of the axle tube/spring pack 'sandwich'- they do nothing to alter body height.

Unfortunately, with the spring pack on top of the axle, the only remedy is to change the spring shackles (or get new springs) if you want to go lower.

Check http://www.sportruck.com/howto/suspension.htm for some general pics/items.

1" or 2" lowering shackles: $10-$60.

[ocnblu]

I'll put a picture of my shackles up. The spring is bolted to the top of the shackle, therefore, a longer shackle will effectively lower the truck. As far as I know, u-bolts are u-bolts, shackles are the brackets with bushings that mount the rear of the leaf spring to the frame.

[balthazar]

>>"As far as I know, u-bolts are u-bolts, shackles are the brackets with bushings that mount the rear of the leaf spring to the frame. "<<

That's the way I know it, too.

[ocnblu]

Well, I just ordered a set of shackles from Stylin' Concepts, made by DJM Suspension. The dude on the phone said they will bring the truck down exactly 2 inches. I'm sure there will be instructions. I'm guessing I just need to jack up the rear of the truck at the frame until there is no tension on the spring and then unbolt it from the factory shackle.

[76ChevyTrucker]

Balth, you're right, I only glanced at the shot.