Leaf spring question

[nsiti]

Hi all,

I am in the process of restoring my 1972 Chevy Suburban 3/4 ton 4x4.

I ordered a full suspension set, with 5" lift including rear shackle flip, from ORD and it seems they miscalculated in the design of the rear leaf springs (the front are fine).

When I ordered the springs I was not asked for the weight of the vehicle, which is stock, except for the 40 gallon fuel tank. Now I am being asked for the weight and thought I would get some advice from you as to how to respond. Any assistance would be appreciated.

You can view my build on this site at: https://67-72chevytrucks.com/vboard/...=839107&page=4

See post 79 and 83 for some pictures of the springs.

Thanks in advance,
Nick

[Short 3/4]

Just go to a truck scale. Weigh it three times. Once each with just one axel on the scale, then with the whole truck on it. That should give them all the info they need

[Richard]

Hard to believe that you are getting so much irrelevant information from ORD. The reason your springs will not compress has nothing to do with the weight capacity of the leaf packs. Has ORD actually seen pictures of the installed springs? There are two options to fix what you have. Move the shackle hanger closer to front hanger to correct shackle angle at unloaded state, or make new springs that have a longer eye to eye dimension in an unloaded state. If the people at ORD you are speaking to are saying anything different. They should not be working there. Ask to talk to the owner Stephen.

[v30crewcab]

your springs are way too short. they need to be 5 or 6 inches longer.

[nsiti]

Originally Posted by Short 3/4

Just go to a truck scale. Weigh it three times. Once each with just one axel on the scale, then with the whole truck on it. That should give them all the info they need

Hi, and thanks for the suggestion. Unfortunately, the truck has been stripped as part of the restoration process, motor removed, etc.

[nsiti]

Originally Posted by Richard

Hard to believe that you are getting so much irrelevant information from ORD. The reason your springs will not compress has nothing to do with the weight capacity of the leaf packs. Has ORD actually seen pictures of the installed springs? There are two options to fix what you have. Move the shackle hanger closer to front hanger to correct shackle angle at unloaded state, or make new springs that have a longer eye to eye dimension in an unloaded state. If the people at ORD you are speaking to are saying anything different. They should not be working there. Ask to talk to the owner Stephen.

Richard, thanks for sharing your thoughts. We have come to the same conclusions. Moving the shackle hanger forward would raise the truck even higher than it already is (which is higher than the specifications call for) and move the axle further off-angle, so that's not an option. Making new springs seems to be the correct route. After getting the run-around from a couple of ORD employees over the past 12+ months, I am now communicating with the owner Stephen, with whom I have shared photos. He told me that the springs were designed for a much heavier truck and asked for the weight of my Suburban. I provided him with the weight and am interested to see what comes next.

Regards,
Nick

[nsiti]

Originally Posted by v30crewcab

your springs are way too short. they need to be 5 or 6 inches longer.

We have come to the same conclusion. Now the vendor needs to agree with us. Thank you very much for your help.

Regards,
Nick

[Richard]

Originally Posted by nsiti

Richard, thanks for sharing your thoughts. We have come to the same conclusions. Moving the shackle hanger forward would raise the truck even higher than it already is (which is higher than the specifications call for) and move the axle further off-angle, so that's not an option. Making new springs seems to be the correct route. After getting the run-around from a couple of ORD employees over the past 12+ months, I am now communicating with the owner Stephen, with whom I have shared photos. He told me that the springs were designed for a much heavier truck and asked for the weight of my Suburban. I provided him with the weight and am interested to see what comes next.

Regards,
Nick

Moving the shackle will most likely lower the truck. Some things to help understand. if you lower the rear of the spring 2" it would only raise height by 1". But you do not consider the spring. Yours are locked up and cannot compress. The 10 leaf Deaver springs on my truck have a bit over 13" of free arch. They compress over half of that with the vehicle weight on them. The springs you have are made similar. Once you free them up you will be surprised how much they compress.

[nsiti]

Originally Posted by Richard

Moving the shackle will most likely lower the truck. Some things to help understand. if you lower the rear of the spring 2" it would only raise height by 1". But you do not consider the spring. Yours are locked up and cannot compress. The 10 leaf Deaver springs on my truck have a bit over 13" of free arch. They compress over half of that with the vehicle weight on them. The springs you have are made similar. Once you free them up you will be surprised how much they compress.

Richard, I see what you're saying so thanks for the info. We had already checked and the shackle doesn't have room to shift forward due to the gas tank (support and hose exit). I spoke with my build team about this some more and there are some other unknowns to this, such as knock-on effects to wheel centering, shock orientation, and differential angle. Overall, doesn't seem like a viable option for us that are looking to do things correctly. In the meantime, I'm still waiting for Stephen at ORD to respond to my email of Monday in which I answered his question about the weight. I'm curious to see what comes back. Cheers, Nick

[Richard]

Originally Posted by nsiti

Richard, I see what you're saying so thanks for the info. We had already checked and the shackle doesn't have room to shift forward due to the gas tank (support and hose exit). I spoke with my build team about this some more and there are some other unknowns to this, such as knock-on effects to wheel centering, shock orientation, and differential angle. Overall, doesn't seem like a viable option for us that are looking to do things correctly. In the meantime, I'm still waiting for Stephen at ORD to respond to my email of Monday in which I answered his question about the weight. I'm curious to see what comes back. Cheers, Nick

Okay, sorry the info does not help. I suspected the main reason for not wanting to move shackle was your tank. Note- a longer spring will make the shackle point down, therefore lowering the rear of the spring. Unless the new spring is made with the added length only to the back. The axle will move toward the rear, much more than moving the shackle The pinion angle will also still change. So all the things you noted will happen whether you move shackle or change spring. Just sayin, you kind of are ovethinkin this. I wont bother anymore and let the path continue as it has. Really, I wish the best of luck you get things sorted out the way you want them.

[kwmech]

For some reason nobody seems to get the rear springs correct on the Suburbans the first time. Went back and forth on my 91. I finally took the new spring pack and the old one to Sacramento Spring, told what I wanted and how much lift. Got them back and they fit perfect and the rear squat was gone

[nsiti]

Originally Posted by kwmech

For some reason nobody seems to get the rear springs correct on the Suburbans the first time. Went back and forth on my 91. I finally took the new spring pack and the old one to Sacramento Spring, told what I wanted and how much lift. Got them back and they fit perfect and the rear squat was gone

Thanks, this is interesting and good feedback.

[nsiti]

By way of follow-up, I was informed by ORD that they will provide a spring to hold 1050# at a 6 to 6.5” loaded arch measured from the spring perch up. I'm not sure what to make of this and have call into them but the owner is away for the week, so I thought I would ask for some feedback from all of you. Thanks!

[Richard]

Originally Posted by nsiti

By way of follow-up, I was informed by ORD that they will provide a spring to hold 1050# at a 6 to 6.5” loaded arch measured from the spring perch up. I'm not sure what to make of this and have call into them but the owner is away for the week, so I thought I would ask for some feedback from all of you. Thanks!

I really was trying to not comment. All I see with info provided is how much new spring will compress and support with a correct mounting. Your springs are not mounted correctly and cannot compress. If the dimensions of new springs are the same as you have now. They will not compress. I would think that those seeing pictures could figure that out? How can they figure a new weight load when the springs you have are locked up? The Free arch eye to eye dimension is what matters in a shackle mounting.
Please look at what I did with my new rear springs in my build thread. Had to purchase two different sets to get what I wanted.
I understand, you purchased "a kit" But when you customize there are always changes needed. I am not a fan of the compression shackle myself. Kept with the tension type. If you had ordered 5" lift springs for the stock mounts from Deaver, Alcan or Atlas. This would have never been a problem.

[v30crewcab]

it looks like the problem is they sent 52" springs in stead of 57" springs. I'm not sure the burbs ever came with 52" springs in the rear.

[Richard]

Originally Posted by v30crewcab

it looks like the problem is they sent 52" springs in stead of 57" springs. I'm not sure the burbs ever came with 52" springs in the rear.

Interesting thought. Never heard of 57" springs offered in any 67-72 light duty trucks. Even later ones after 72. The later ones have offered 56". Maybe a typo. None the less, first I have heard or seen of longer than 52" rears in 67-72.

To nsti maybe you could post measurements from eye to eye on spring as well as front hanger bolt to rear shackle bolt?

A thought came to me. Maybe the springs you have installed are 5" lift designed for a tension shackle. As I see them, they would probably work well and function properly with a tension shackle.
The springs sent with the shackle flip would be 3" lift. The shackle flip provides 2" of lift. Why ORD offers these two options confusing people wanting custom springs. I do not understand.

[nsiti]

Originally Posted by v30crewcab

it looks like the problem is they sent 52" springs in stead of 57" springs. I'm not sure the burbs ever came with 52" springs in the rear.

Thanks, I think this is generally a correct thought. I have been told there are 52 and 56 inch springs in some configurations of that era.

Originally Posted by Richard

Interesting thought. Never heard of 57" springs offered in any 67-72 light duty trucks. Even later ones after 72. The later ones have offered 56". Maybe a typo. None the less, first I have heard or seen of longer than 52" rears in 67-72.

To nsti maybe you could post measurements from eye to eye on spring as well as front hanger bolt to rear shackle bolt?

A thought came to me. Maybe the springs you have installed are 5" lift designed for a tension shackle. As I see them, they would probably work well and function properly with a tension shackle.
The springs sent with the shackle flip would be 3" lift. The shackle flip provides 2" of lift. Why ORD offers these two options confusing people wanting custom springs. I do not understand.

The bolt to bolt measurement in the attached photo is almost exactly 51 inches. We have considered that there may have been a build error having to do with the shackle flip (which our spec sheet says is designed to provide 4 inches of lift) or the spring is simply too short (or both!). Unfortunately, I am unable to measure the spring from eye to eye as they are currently still installed. But the photo illustrates they may be too short. I'm still waiting to hear back from the owner to clarify the specs and shipping logistics.

[b454rat]

Looks like the shackle flip was installed in the 56" spring holes. The frames are the same, only difference is spring length between 1/2-3/4 ton. Front hanger is the same regardless. The holes should be there to move the shackle flip forward 4".

[57taskforce]

1/2 ton and 3/4 ton pickup use the same spring length and frame at least for 69-72. That’s why they use the same lift kit. 67-68 use different rear springs so maybe there’s truth there I can’t confirm. There aren’t any extra holes in the frame I’m aware of at least not on my K20.
I do however agree that it looks like that setup would be a lot more happy with 56” springs. I don’t really know much about the suburban stuff.

[b454rat]

Don't know much bout the 67-72s lol. I'd say just move the hanger forward. If the axle is in the right spot, has the lift you want, then drill holes n move it.....

[Richard]

Originally Posted by nsiti

The bolt to bolt measurement in the attached photo is almost exactly 51 inches. We have considered that there may have been a build error having to do with the shackle flip (which our spec sheet says is designed to provide 4 inches of lift) or the spring is simply too short (or both!). Unfortunately, I am unable to measure the spring from eye to eye as they are currently still installed. But the photo illustrates they may be too short. I'm still waiting to hear back from the owner to clarify the specs and shipping logistics.

Thanks for posting that. The hanger location coincides with a stock 52" spring. Apologize, was going off of memory on offerings from ORD on the shackle flip. The flip will you have is designed to drop rear of spring 8" for a 4" lift. Springs supplied should only be 1" over stock for a 5" lift. By seeing the arch it is obvious they are way over that. You have the wrong springs. I would bet a dollar if you installed these tension hangers from ORD. It would sit correctly. https://www.offroaddesign.com/tensio...hevy-pair.html
Another question if you do not mind. Did you have to spread the spring eyes to get get them installed?

[v30crewcab]

you sure they didn't send you 4 front springs? the fronts are shorter than the rear. those rears are too short to even work with the stock shackle setup. run a tape measure around the backside of the spring to confirm length. either way, they should be stock height with a shackle reversal unless you're wanting 8" or more lift.

[Orange Crate]

The position of the rear shackle is not correct. When weight is added to the back the shackle as it is will try to move up. This is not right, it should pivot towards the rear. At a minimum the shackle should be vertical or slightly angled to the rear.

[b454rat]

After trying to get a closer look, I don't see a hoover (overload) spring. I think you have a front spring on the rear. It would make sense since it looks to be way short....

[Richard]

@ Orange_Crate, what I have pointed out since I saw this in the build thread.
@ v30crewcab please look at my build thread to see how a tension setup works.
@ b454rat understand the springs are custom spec 10 leaf springs made for ORD by Alcan most likely. Not an off the shelf "kit" spring like Tuff Country.
A bit from the tension shackle link I previously posted.
"With our custom spring systems, this will let you get 5” of lift from the rear while keeping the travel benefits of the tension shackle system."
Why ORD does insist on pushing the shackle flip with custom springs, I do not know?
Bottom line OP has the wrong springs for his application.