Swapping coils for leaves:

[conoverbandit]

Hey Y'all,
I got a friend who has a 69 lwb c-10 pick up with the trailing arm rear suspension set-up.The coils have long ago lost thier ability to hold up a load and he wants to see if there is any way to put leaf spring suspension in under his rig.He does have a 75 lwb 2 by parts truck with axle and leaves inunder it. Would this interchange? He wanted to set his 69 body up on the 75 chassis, but the frames are bent different, the 69 bends after cab while the 75 bends under the cab, so we figured that route was shot. So he suggested taking the rear suspension out of the 75 and installing inunder the 69. I told him I thought it would or could work, but just had a brain storm..... the 73-up trucks are narrower? then the 67-72's? I had a 91 k-5 that we sold and I took the hitch off the back before we sold it, tried to put it on my 75 k-10 and it was 2in to wide to fit, but it fit on my dad's 71 GMC 2 by truck no problem.If this is the case he'll either have to re do the spring mounting plates or find another rear. Lucky for him I got an eaton 8 lug (which is what he wanted to go with anyways) from a 71 chevy camper special, this axle should be the samw width (plate to plate wise) as his current one? am I even close here? Thanks for the help in advance,

[fine69]

Why not just buy new rear coils and some heavy duty shocks? Less than $150 invested. And way less time. Any auto parts store can order the coils for him.
I think it would be foolish to do such a swap just because of saggy coils.

[1969K10]

I'm fairly certain I'm going to be doing this same thing to the 67 I just picked up. Keep a journal and some pics to post so I can see what I'm getting into before I start. I wish I could help on this, but I haven't even gotten the bed off the 67 to see how it compares to the frame on my '72 w/ leafs...

[lofly'a]

i hope i'm not getting to far off or hijacking your thread, i also have a question....my 71 gmc project has leaf rearend and i'm planning on swapping to trailing arm from a lwb parts truck. who has done the leaf to coil swap and what did you encounter? the frames are'nt different out back are they? that's my only worry.

on the issue of swapping, and i've ridden in both, the coil rear ride and handling is superior to leaves if you don't carry a heavy load, and leaves way out perform coils for tow/haul needs. to do a coil to leaf swap would require some cutting and welding unless you have another rearend, and i could be wrong but i think the 73-87 rears are wider than 67-72's.

[neonlarry]

You can swap the leaf setup from a 67-72 truck onto one with trailing arms. But why? I understand that there are ppl that like leafe spring trucks, but I probably wouldnt buy a 67-72 unless it had coils. lol

[conoverbandit]

I think he'd really like to swap his truck for one with leaves, but this is the route he's decieded to go I think, just trying to help him gather information at this point. It's not the "ride" he's after, it's the ability to haul loads and stuff. I can get pic's of his truck to see if anyone has a leaf sprung lwb truck to trade.At this point if he could find a leaf sprung chassis for his ........

[StingRay]

Put new cargo coils on it and find a set of half leaf overloads. Ask for em on the parts board. Everybody that's ever parted a truck or two has a set lying around. For leafs it would be best to swap em off of a 67-72 leaf truck. I can't understand why anybody would want to though. I have a leaf SWB frame that I'm going to convert to coil!

[Longhorn Man]

stock for stock, the coils and leafs have the same rating.
And with coils, if you overload it, (like when i had 2200 or so pounds of bricks in the old GMC) the coils will go into coil bind and just stack up...after that point, only the strength of the axles are all that's holding you back...that and tires.

[lofly'a]

i want coils, got a complete 71 gmc leaf sprung truck and i don't want leaves. not going to haul or tow much of anything (pretty much of cruiser). the question is/was, what can i expect in the way of obstacles when doing this swap? i do have plenty parts to do the swap. i agree with you for the most part longhorn, but you forgot to mention how the coil setup tends to break the shock mounts off when overloaded often. have welded quite a few shock anchors back on.

[Longhorn Man]

Hmmm, I DID have to welb mine back on too...but it was from being an old POS...although it was probably overloaded a few times in it's life, esp with the mentality of the dope smokin old man.

[1970 CST Short Wide]

I have the back half of a frame with the leaf spring perches attached. For a small fee and shipping I could be persuaded to remove and send them to you

[Longhorn Man]

I think shipping from Cali to north carolina might be a little unreal.

[cduster]

Originally Posted by StingRay

Put new cargo coils on it and find a set of half leaf overloads. Ask for em on the parts board. Everybody that's ever parted a truck or two has a set lying around. For leafs it would be best to swap em off of a 67-72 leaf truck. I can't understand why anybody would want to though. I have a leaf SWB frame that I'm going to convert to coil!

This would be easiest IMO. I have a set of overloads laying around and available, as I am sure many guys here do.

Dan

[GlennBrittain]

I have been considering changing my coils out to a late model rear end and leaf. I have been told by the local auto machine shop, who also does some restoration it works well in these trucks. I have not made any measurements yet as I still have the bed to remove on my frame. I had planned on posting a request for info also. I would like to know if anyone has made this swap.
Here in East Texas the older farmers always carried some extra weight in the back of thier trucks so they would handle better on out poor dirt roads. I am told by changing out to a late model rear end with the longer leaf's the truck will handle better. This is a lot of time and money that could be potencially be wasted.

[cableguy0]

no offense guys but the coil spring suspension is a much better setup and if you use 3/4 ton coils there wont be much you cant haul around my heavy half 72 has had over 3k pounds in the bed it was sunk on the overloads but it hauled it anymore than that and your asking to break an axle or the rear itself

[GlennBrittain]

None taken, thanks for the info

[Longhorn Man]

heavy half?

[A.P.]

Have you guys seen this article: http://www.earlyclassic.com/Tech.asp...=Spring%20Time

Its in Early classics web site. Its about GM Coil vs leafs springs. Good info.

[GlennBrittain]

Good info, heavy loads are not a consideration in my decision, sway and sliding sideways after a washout on a dirt road or pot hole on the pavement is what I am looking to minimize. From the information I have recieved or have been directed to, I would be better off to to stay with the coil/trailing arm setup, with the aftermarket upgrades

[c10-377]

On my 69 pickup I put leaves on it. It wasnt very hard jsut took a little time. Mainly just drill holes in the frame so it can mount up properly and bolt it up.