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Coil Spring Rear Suspension

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Interesting thread . I’ve been entertaining the idea of playing around with leaf combos to make my truck a little less taunt. I know nothing about leaf springs suspensions and asked a friend about removing a leaf , and he said that would be disastrous for the handling . I was hoping I could remove one of the thicker ones on the bottom to help soften the ride and lower the rear just a little . This is a toy truck for me and won’t see a lot of serious work , so ride comfort is important - we won’t even bring up my bad back. 
So it is possible to remove a leaf without serious consequences? 

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A shorter fat bottom one is ok to take out and try. The top ones have all the give and as they crush down the bottom ones add progressively more resistance. The top leaf packs are what keep the axle under the truck and resist side to side movement. On a coil spring vehicle a panhard bar can be used to stop side to side movement of the axle.

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When I lived in NJ I was restoring my jaguar xk140 and needed a new set of leaf springs. It was my intention to rally the car so I had a spring shop replicate the original spring set with two additional leafs of the same thickness  for stiffness.  I get no sway or lean in the turns now.  Additionally I had a set done for another car that rode like a truck. On that set they used thinner leaf material and removed 1 from the set but made the remaining leafs longer to make up for the subtraction.  If you have a spring shop in your area they can do marvelous things.

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PdlZJfk.jpg

 

Normally 5 leaves on my goon. I had an extra set so I have two number 4 leaves (down from the top) I had to trim end off so it clears the lump on the bottom of the one above it. This would hold more weight so the car wouldn't settle as much effectively raising it very slightly. At the same time I added lowering blocks. Came out alright and matches the lowered stiffer spring front. Also has some really HD shocks from a truck. (not in this picture) The shock shaft is visibly thicker than a car shock and has a rubber bellows on them. Something very much like

 

RS5240.jpg

 

Yes it's firm but ok around town. Often on the highway at speed a dip can jolt you but it never will bottom out and that is what I was after. You know that seats have come a long way in 44 years and the original buckets were the same I had in my 620 and they are killer uncomfortable. Good seats can also help with a firm ride as are the tires.

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I’ve solved the seat issue , but like to settle the bounce a little . I think I’ll try removing the bottom spring and give it a whirl . 

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19 hours ago, Madkaw said:

Interesting thread . I’ve been entertaining the idea of playing around with leaf combos to make my truck a little less taunt. I know nothing about leaf springs suspensions and asked a friend about removing a leaf , and he said that would be disastrous for the handling . I was hoping I could remove one of the thicker ones on the bottom to help soften the ride and lower the rear just a little . This is a toy truck for me and won’t see a lot of serious work , so ride comfort is important - we won’t even bring up my bad back. 
So it is possible to remove a leaf without serious consequences? 

 

18 hours ago, jagman said:

When I lived in NJ I was restoring my jaguar xk140 and needed a new set of leaf springs. It was my intention to rally the car so I had a spring shop replicate the original spring set with two additional leafs of the same thickness  for stiffness.  I get no sway or lean in the turns now.  Additionally I had a set done for another car that rode like a truck. On that set they used thinner leaf material and removed 1 from the set but made the remaining leafs longer to make up for the subtraction.  If you have a spring shop in your area they can do marvelous things.

Removing leaves from the pack is totally acceptable, but depending on the specific leaf pack, you may want to remove short or long springs. Your friend that told you it would be a bad thing to do, maybe based on his personal experience he is correct, but in most cases, I would like a soft spring and a stiff roll bar. Remember that this is a truck that was designed to carry loads, and if your future use does not include carrying loads, then take out as many springs as you like to get the spring rate where you want it.

 

I often make adjustments to leaf packs to get ride height and spring rate where I want it. On my 1957 Land Rover, I removed three leaves from the rear pack (it had eleven individual leaves) and then put one back in upside down. Putting the leaf back in upside down helped lower the height, but kept the spring rate where I wanted it.

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There’s about 2-1/2” difference in fender clearance . The back is jacked up to high for me.

This is a new leaf pack , but the original also had the rear high . I don’t like the look and don’t care much for the bouncing Betty ride . I guess I’ll start with the shorty overlord spring . But isn’t there a centering pin on the bottom leaf? I can’t remember . Hell- I would even turn down the torsion bars as far as ride height . Then I would have to recheck camber I guess . I plan on running 16” wheels , so I’ll lose a little of the rubber cushion from less sidewall . Don’t want any 33’s either . I don’t want to turn this truck into a doggy ride . It’s quick enough for a 83 mini truck for me . 

C8B25145-C75F-4E68-B387-38E3CD4E32BD.jpeg

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Madkaw, please let us know how this turns out. It sounds like we are wanting similar results, with different reasons. 

 

Don

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To me this appears to be a 4wd truck, what are the new leafs you installed on it, where did they come from?

 

17 hours ago, Madkaw said:

There’s about 2-1/2” difference in fender clearance . The back is jacked up to high for me.

This is a new leaf pack , but the original also had the rear high . I don’t like the look and don’t care much for the bouncing Betty ride . I guess I’ll start with the shorty overlord spring . But isn’t there a centering pin on the bottom leaf? I can’t remember . Hell- I would even turn down the torsion bars as far as ride height . Then I would have to recheck camber I guess . I plan on running 16” wheels , so I’ll lose a little of the rubber cushion from less sidewall . Don’t want any 33’s either . I don’t want to turn this truck into a doggy ride . It’s quick enough for a 83 mini truck for me . 

C8B25145-C75F-4E68-B387-38E3CD4E32BD.jpeg

 

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When removing or adding leaves, use c-clamps on either side of the center pin to help hold the pack together while loosening the center pin nut. After the center pin is removed, you can now loosen the c-clamps to get access to the leaves. Do not try to remove the center pin without some sort of clamp, or you'll get a slap in the face, literally.

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7 hours ago, wayno said:

To me this appears to be a 4wd truck, what are the new leafs you installed on it, where did they come from?

 

 

I believe it was general spring . I think they were around 250$ shipped 

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6 hours ago, Stoffregen Motorsports said:

When removing or adding leaves, use c-clamps on either side of the center pin to help hold the pack together while loosening the center pin nut. After the center pin is removed, you can now loosen the c-clamps to get access to the leaves. Do not try to remove the center pin without some sort of clamp, or you'll get a slap in the face, literally.

I really appreciate the info . I have a young help for those jobs . He likes learning all the shit jobs 🙂

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6 hours ago, Stoffregen Motorsports said:

When removing or adding leaves, use c-clamps on either side of the center pin to help hold the pack together while loosening the center pin nut. After the center pin is removed, you can now loosen the c-clamps to get access to the leaves. Do not try to remove the center pin without some sort of clamp, or you'll get a slap in the face, literally.

Do you think removing one leaf will change the height by much ? 

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Well, it's not just the thickness of the leaf, it's the added spring rate. How much do you want to lower it? If more than 1/2 inch, then maybe you remove one of the longer leaves and one of the short ones.

 

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If this is a 4wd and still has the stock leafs it only has 2 arched leafs and 2 over load leafs, I would not be removing the second arched leaf and removing the over load leafs will change nothing, fact is I am remembering that all 720s had 2 arched leafs and 2 flat overload leafs except for the Cab/Chassis, I would not be messing with the stock leaf packs of a 720.

 

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