howeitsdone Posted December 31, 2021 Share Posted December 31, 2021 My main leaf springs have seen better days. So I started down the "what JY swap will work?" path before dropping $500+ and came across old GM 1-ton springs. They are only 1" shorter in the rear than the Comanche's (30" vs 31"). They also use 9/16" bolts. Ours are M14, but it's literally .01" difference so should snug in there just fine. So I got to wondering if you could swap them & if anyone has tried. I've already got drop shackles which have two different holes to adjust if needed. You can find these packs easily at a JY for $50 or even buy the main leaf for $75 new. Obviously I'm not sticking 9 springs under my truck, but thinking I could make a bastard pack if needed. I'm not sure the arch though. Anyone have any insight? Link to comment Share on other sites More sharing options...
Pete M Posted January 1, 2022 Share Posted January 1, 2022 my biggest concern is that the shackle angle will be wrong and it might invert when the truck comes down off a lift or flexing offroad. if you keep your main leaf, you can swap all sorts of packs under them. what is it that you want the new packs to do? lift? greater capacity? Link to comment Share on other sites More sharing options...
howeitsdone Posted January 1, 2022 Author Share Posted January 1, 2022 Dirt road is about the only off-road it'll see in this condition, and no one is lifting it but me so those are a plus I suppose. You're thinking I should keep my main even though they're bent the wrong way? Curious what's the reasoning? Link to comment Share on other sites More sharing options...
Pete M Posted January 1, 2022 Share Posted January 1, 2022 I simply added a new leaf between the main and the one below it to provide support. Link to comment Share on other sites More sharing options...
Pete M Posted January 1, 2022 Share Posted January 1, 2022 this is what I mean by shackle inversion. if the shackle is too short, or the leaf is too short, the shackle can actually move forward after full droop. Link to comment Share on other sites More sharing options...
Eagle Posted January 3, 2022 Share Posted January 3, 2022 On 12/31/2021 at 10:57 PM, PocketsEmptied said: Dirt road is about the only off-road it'll see in this condition, and no one is lifting it but me so those are a plus I suppose. You're thinking I should keep my main even though they're bent the wrong way? Curious what's the reasoning? How are they bent the wrong way? I dodn't see that in your photo. Link to comment Share on other sites More sharing options...
howeitsdone Posted January 3, 2022 Author Share Posted January 3, 2022 I guess I mean they're just so worn that once under an actual load and start to flatten, the main starts to invert. Don't have a pic showing since I don't have a load in the bed. But if there's no integrity issue with the main doing this then I could do as Pete suggested and add another leaf under it. Ultimately was trying to find a JY main leaf replacement. Thought this was a decent idea. @Pete MDo you remember what that leaf came off of? Looks like it should be about 50-52" or so at the length you have in your photo. I'm sure I would need to cut something Link to comment Share on other sites More sharing options...
Pete M Posted January 3, 2022 Share Posted January 3, 2022 my AAL is just an MJ main leaf with the eyes cut off. I wanted full support of the main and this was the only way I could figure out how to do that. Link to comment Share on other sites More sharing options...
DirtyComanche Posted January 3, 2022 Share Posted January 3, 2022 I looked at these before I think... And they are flatter than factory MJ springs. You would also have to do something about the shackle location. I wanted them to go SOA and not get 5-6" of lift. I didn't buy them because it cost too much to gamble at the time, and the springs I had proved to perform fine in the end, even if a little too tall. Edit, I think I was looking at "C" truck (2wd) springs actually. I need to go dig into that again. Link to comment Share on other sites More sharing options...
zomeizter Posted January 8, 2022 Share Posted January 8, 2022 I scored a set of rear leaves off a 99 Silverado HD which will be swapped in once I get some home time. I mocked them up under the 'manche and they look like they could work, maybe some shackle bracket relo will get them mounted... Link to comment Share on other sites More sharing options...
DirtyComanche Posted January 9, 2022 Share Posted January 9, 2022 On 1/5/2022 at 2:54 AM, saveevryjp1998 said: It sure doesn't look like the GM springs have anywhere near enough arch according to the charts. Which charts are you using? I'm looking for springs that are flatter than the stock MJ springs, so I can go SOA with a little higher spring rate and not get more than 4"~ lift. If that's possible without a custom spring. Link to comment Share on other sites More sharing options...
howeitsdone Posted January 9, 2022 Author Share Posted January 9, 2022 4 hours ago, zomeizter said: I scored a set of rear leaves off a 99 Silverado HD which will be swapped in once I get some home time. I mocked them up under the 'manche and they look like they could work, maybe some shackle bracket relo will get them mounted... Technically a lot of springs will work with shackle mount relocation lol, but I was trying without doing so. I don't have a welder or I would try. 1 hour ago, DirtyComanche said: Which charts are you using? I'm looking for springs that are flatter than the stock MJ springs, so I can go SOA with a little higher spring rate and not get more than 4"~ lift. If that's possible without a custom spring. Technically the Comanche is 11.75" from bottom to top of eye. The GM springs are 9.125" from bottom to top of eye. However, if you were to keep all 8 leafs, I have no idea how much the rear end would sit down since it would have a lot more reinforcement. But you could certainly remove them. Early Ford Ranger springs are only 3/8" shorter than the Comanche's and the total height is much lower. Maybe you could get away with those and an AAL? Dunno Link to comment Share on other sites More sharing options...
zomeizter Posted January 9, 2022 Share Posted January 9, 2022 12 hours ago, PocketsEmptied said: Technically a lot of springs will work with shackle mount relocation lol, but I was trying without doing so. I don't have a welder or I would try. My bad, I thought you were after swapping in GM 1 ton springs... Link to comment Share on other sites More sharing options...
DirtyComanche Posted January 12, 2022 Share Posted January 12, 2022 On 1/8/2022 at 6:24 PM, PocketsEmptied said: Technically a lot of springs will work with shackle mount relocation lol, but I was trying without doing so. I don't have a welder or I would try. Technically the Comanche is 11.75" from bottom to top of eye. The GM springs are 9.125" from bottom to top of eye. However, if you were to keep all 8 leafs, I have no idea how much the rear end would sit down since it would have a lot more reinforcement. But you could certainly remove them. Early Ford Ranger springs are only 3/8" shorter than the Comanche's and the total height is much lower. Maybe you could get away with those and an AAL? Dunno A Ranger lift spring look like a possible good option, if one could find them, or add another cut down main leaf. Or like you say, take the GM spring and maybe pull 3 leaves out of it. Definitely some options. Link to comment Share on other sites More sharing options...
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