1-ton leaf spring swap

[equality72521]

Hey everyone, I've got a 1987 Chevy V20 with a heavy-duty RPO. It has a Corporate 9.5" 14-bolt in the rear with 13" drums. The rear leaf springs are OE HD 8/1 56". They are getting tired.
Are 1-ton springs a direct-fit replacement? Both standard and heavy-duty 1-ton springs are actually cheaper than HD 3/4-ton and they seem to be the same size (true, lower arch, lower ride - don't really care). Center-pin on mine is 26" from the front. I plan on replacing the springs, u-bolts and shackles. The hangers look...serviceable.
Questions: Is this possible? Can I use new 3/4-ton U-bolts and the existing anchor plate (also serviceable), or do I need new 1-ton u-bolts and a new 1-ton anchor plate that goes below the axle? Anything else I'm missing?

Thanks!

 

[CSFJ]

Unless I'm mistaken, the width of the spring packs on the 1 ton will be narrower to accommodate the dual rear wheel trucks. And you might want to double check the rear axle you have, I was under the impression that the heavt duty 3/4 trucks got the 14 full float with the big ring gear. Where as the semi float 9.5 was under the light duty 3/4.

 

[equality72521]

So, I may have been a little hasty in my OP. After looking closer at the truck and the RPO codes, it has a G51 code for the rear springs, which I guess is a different heavy duty variant. As such my rear springs have *8* leaves total, not 9. The widths listed on both 3/4 and 1-ton springs that I've seen is the same: 2.5"
And yes, you're right about the rear axle - it is in fact the light duty 9.5". My truck is an enigma of factory options that must have been hand-picked by the original owner for a specific reason. Silverado...with no AC...? Quad shocks, heavy springs, big brakes...light duty axle? Heavy duty radiator, factory oil cooler...TH400 trans....

Here's a few relevant RPOs:

C6P GVW RATING 8,600 LBS/3,900 KG
F51 SHOCK ABSORBERS FRT & RR, HD
F60 SPRING FRONT HEAVY DUTY
GQ1 AXLE STD RATIO
GT5 AXLE REAR 4.10 RATIO
G51 SPRING REAR HEAVY DUTY, VAR 2
JB7 BRAKE POWER, DISC/DRUM, 8,400 LBS
J55 BRAKE SYSTEM HEAVY DUTY

 

[CSFJ]

Lol. Gotta love the days when you could order a vehicle the way you wanted it, instead of picking from 3 or 4 option packages. Completely eliminated the oddball stuff like that. I'll lay a tape measure across the springs on my truck when I get home, I've got a light 3/4 and a 1 ton frame sitting next to it, waiting to be swapped under. You could be correct on the springs, I keep hearing that there are some differences, to accommodate the duals, but haven't found out exactly what yet.

 

[CSFJ]

You're correct on the spring width. Just measured both of mine, 2.5" on the nose.

 

[chengny]

Call these guys - they are all over this. They also usually have the correct spring sets for your truck on the shelf:

Donovan Spring & Equipment Co Inc

Address: 6 Enterprise Rd, Londonderry, NH 03053

Phone: (603) 669-2250

And they are very reasonable when it comes to pricing. Recently - well not that recently, it was in March of 2013 - I bought a set of 9 stacks with auxiliary springs for my 86 (single wheel rear axle K30) from them.

That included everything except the hangers - like you, my hangers were still serviceable. I got shackles, shackle bolts, nuts & washers. Also included all the u-bolts & nuts/washers, upper spacers and anchor plates. This was all real quality, heavy duty commercial truck stuff.

I think I paid around $500 - maybe not even that. Below are some images of what was supplied (and no comments about my use of old encyclopedias & alloy rims to increase effective jack-stand height - heard it all before):

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[chengny]

And here are some shots of how these springs (and the associated hardware) look after 4 years. They have held up well:

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A good hint to extend the service life of the anchor plates and u-bolts:

Refer to the last photo and note the pooled water in the anchor plate - as indicated by the yellow arrow. Prior to installing new anchor plates and u-bolts/washes & nuts, drill a 1/4" drainage hole in each of the u-bolt cups. This will greatly decrease the rate at which the plates and bolts become wasted due to rust. I had to drill them after they were in place - it wasn't that hard but it is easier on the bench.

 

[CSFJ]

Call these guys - they are all over this. They also usually have the correct spring sets for your truck on the shelf:

Donovan Spring & Equipment Co Inc

Address: 6 Enterprise Rd, Londonderry, NH 03053

Phone: (603) 669-2250

And they are very reasonable when it comes to pricing. Recently - well not that recently, it was in March of 2013 - I bought a set of 9 stacks with auxiliary springs for my 86 (single wheel rear axle K30) from them.

That included everything except the hangers - like you, my hangers were still serviceable. I got shackles, shackle bolts, nuts & washers. Also included all the u-bolts & nuts/washers, upper spacers and anchor plates. This was all real quality, heavy duty commercial truck stuff.

I think I paid around $500 - maybe not even that. Below are some images of what was supplied (and no comments about my use of old encyclopedias & alloy rims to increase effective jack-stand height - heard it all before):

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

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And here are some shots of how these springs (and the associated hardware) look after 4 years. They have held up well:

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

A good hint to extend the service life of the anchor plates and u-bolts:

Refer to the last photo and note the pooled water in the anchor plate - as indicated by the yellow arrow. Prior to installing new anchor plates and u-bolts/washes & nuts, drill a 1/4" drainage hole in each of the u-bolt cups. This will greatly decrease the rate at which the plates and bolts become wasted due to rust. I had to drill them after they were in place - it wasn't that hard but it is easier on the bench.

Good info to know. If things go as planned, I'll be contacting them this summer after I get my frame blasted and painted.

 

[equality72521]

Appreciate the info guys, thanks.