Suburban leaf spring choice - sagging rear - question on stock ride height

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90Supurban

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My V1500 suburban rear springs are apparently sagging, but I understand the rear is often sitting lower than the front on many of them. I measured center of hubs to fender line, and the front is around 23" with the back about 20". Looks pretty bad. All original springs as far as I know, I believe nothing was ever modified on this truck. I did replace the leaf spring bushings in the front, have not done the back yet, as it is going to need springs anyways. The new front bushings should not affect ride height anyways, especially since I drove it around the property with the bolts loose, and then torqued them with it on level ground. Body bushings are intact.

What is a typical center hub to fender measurement on these trucks? Stock rear spring options are 5-leaf 2000 lb, and 7-leaf 2300 lb. I could just put new stock replacement 5-leaf springs in, but I have a suspicion that, after they settle out, it is still going to sit lower in the back.

I don't plan on doing much, if any, towing with it, and would rather not over spring it. Would it be best to find a 2-3" lift aftermarket rear spring? All the reviews I have found state they ride hard. I really just want to level it out, or an inch of rake (rear higher) just to be sure. Leaf springs are too expensive to just try this one or that one, so I am hoping the square body experience of the members will help to avoid that!
 

legopnuematic

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You may not know, squarebody trucks the front fender opening is taller than the rear wheel opening is.

I do not recall what the difference is but I’d say about 2”

I’d re-measure at the upper body line or bottom of the rocker panel and see what you get.
 

Goldie Driver

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If I did this right, the link below will give you some more dimensions to check on page
16.

It's from the GM Heritage website.





*EDIT* No idea why the links say sight maintenance. :think:
 

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GM Heritage lists an overall height of 73.8" for the op's vehicle but doesn't say where on the roof line that measurement was taken. A useless number considering even non-stock tire size will affect the results.
 

Goldie Driver

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GM Heritage lists an overall height of 73.8" for the op's vehicle but doesn't say where on the roof line that measurement was taken. A useless number considering even non-stock tire size will affect the results.
Ground to top of rear load floor of 30.1 might help. Dimensions of prior year's may help also - I want to look at the 1980 data.

Page 4 gives a GT dimension plus 40 inches to the rooftop.

 

bucket

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You may not know, squarebody trucks the front fender opening is taller than the rear wheel opening is.

I do not recall what the difference is but I’d say about 2”

I’d re-measure at the upper body line or bottom of the rocker panel and see what you get.

Yeah, measure at the rocker panel. If the rocker panel is level, the truck is level.
 

bucket

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Also, if you are happy with how the truck rides, just install lift blocks. Without seeing pictures, I'm betting you won't need more than 2" to do what you want. Simple, cheap and doesn't change the spring rate.

And before anyone starts saying "lift blocks are bad, blah, blah blah..." They are perfectly fine. Use quality cast steel blocks and quality 5/8" u-bolts. Torque them properly and then again after a couple hundred miles. All will be well. There's literally millions of trucks driving around with factory-installed lift blocks up to 4" tall.
 

legopnuematic

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Also, if you are happy with how the truck rides, just install lift blocks. Without seeing pictures, I'm betting you won't need more than 2" to do what you want. Simple, cheap and doesn't change the spring rate.

And before anyone starts saying "lift blocks are bad, blah, blah blah..." They are perfectly fine. Use quality cast steel blocks and quality 5/8" u-bolts. Torque them properly and then again after a couple hundred miles. All will be well. There's literally millions of trucks driving around with factory-installed lift blocks up to 4" tall.

For a data point, every 2nd gen dodge 4x4 truck has 4" factory blocks in the rear. 1500's to 3500's all have them.
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Now stacking blocks on the other hand...
 

90Supurban

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Thanks for all the replies! I did not know about the wheel opening being different. They had t he same shape front and back, so I didn't consider that. But now that you mention it, I can see it. I will measure at the rockers to put a number on it, but there is definitely some sag.

I am surprised to hear that Dodge uses that much block, especially if it has a torquey diesel.
 

bucket

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Thanks for all the replies! I did not know about the wheel opening being different. They had t he same shape front and back, so I didn't consider that. But now that you mention it, I can see it. I will measure at the rockers to put a number on it, but there is definitely some sag.

I am surprised to hear that Dodge uses that much block, especially if it has a torquey diesel.

Ford has for a long time too.

Like I said, there's literally millions of them out on the road.
 

89Suburban

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I measured from the ground to the pinch welds and there is only 1" difference between the back and front. It's an optical delusion!
We messed around with this before here.


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89Suburban

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The whole rear of the body tapers in.
 

bucket

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We messed around with this before here.


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I forgot you did those pictures!
 

bucket

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I measured from the ground to the pinch welds and there is only 1" difference between the back and front. It's an optical delusion!

Hey, I guessed right! Lol. A simple 2 inch block will get you 1" of rake to combat the illusion.

Or if you are good with just getting it level, you can get a pair of 1" "zero rates" from Offroad Design. They are basically a 1", solid steel block but they actually bolt into your spring pack.
 

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