3600 rear leaf spring options? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

51 3600 · 03-17-2018, 09:23 PM

Been on this forum almost two years mostly lurking, learning and buying a few items from members. Getting to a point where I now have questions I haven't seen covered here or I've just missed them. This is my first AD truck (previous experiences with Karmann Ghias and Shovelheads) so a lot of ignorance behind my questions.
I have a '51 3600 I'm trying to upgrade to use as a reliable, daily work truck. I flip houses so it needs to haul sheetrock, flooring, mulch, etc. So far truck is down to frame, unwanted items removed, frame blasted and painted, Blazer front suspension installed, Exploder 8.8 rearend with 3.73 diff & traction-lock ready to install, and 2001 Tahoe purchased for donor 5.3LS & 4L60e sitting in the wings.
Keeping a leaf spring rear suspension but would like to update it with newer wider (2.5") leaf springs for better ride/handling but keep load capacity. Also was hoping to utilize the original spring hangers which I know are made for 1.75" springs but thought inner side of hanger could be welded up and then machined to accommodate the the wider leaf. And rather than have a custom spring made is there a vehicle out there that has a appropriate spring (2.5" wide x 47" long) that would work. I know square body 3/4 tons have the kind of setup I'm trying to mimic but springs are a lot longer.
Any help and suggestions greatly appreciated. Al

ADchevys · 03-19-2018, 07:49 AM

Just got done putting a Firebird reared under a 54 3600. We used early 80’s 1/2 ton c10 leaf springs and hangers. The hangers bolted to the side of the frame, we put the rearend on top of the leaf springs.

whitedog76 · 03-19-2018, 09:00 AM

Quote:

Originally Posted by ADchevys

Just got done putting a Firebird reared under a 54 3600. We used early 80’s 1/2 ton c10 leaf springs and hangers. The hangers bolted to the side of the frame, we put the rearend on top of the leaf springs.

Did you have any clearance issues with the rear running board mount?

I know one of the issues I've ran into with my 54 is that the forward spring mount is up against the rear running board mount as it is.

I've looked at Chevy Colorado, Ford Ranger, and even Jeep XJ rear springs as an alternative myself. I also have planned on using Ranger Spring mounts.

The Jeep seem to be the best for fitment, but they have no real load potential since they don't have a lower overload spring.

I've complicated things by buying an IFS frontend. So, doing the axle over spring setup may be what I will need to do.

mobileortho · 03-19-2018, 09:33 AM

Quote:

Originally Posted by ADchevys

Just got done putting a Firebird reared under a 54 3600. We used early 80’s 1/2 ton c10 leaf springs and hangers. The hangers bolted to the side of the frame, we put the rearend on top of the leaf springs.

Any pics?

ADchevys · 03-19-2018, 06:35 PM

What’s a good site to host pictures. We removed the back running board mount.

whitedog76 · 03-20-2018, 09:16 AM

If you have pics on your computer/tablet, you can upload them to this sight in the advanced settings.

dsraven · 03-20-2018, 09:51 AM

before you go and install a bunch of heavy duty springs to haul around a heavy load, think about what you have for brakes to stop the heavy load.
a stop by your local spring shop seems to be the next step. if doing this for a long time daily driver you would do yourself a favor if you simply get a set made to fit your truck. a new set of spring hangers may not be a bad idea to match up with some wider springs or, for a softer ride with no load, install some overload springs above your regular springs that contact some frame "slipper" brackets when the truck is loaded sufficiently. that way you ride on 1/2 ton springs until you get a heavy load, then the overload springs help out. still gotta be able to stop the whole thing though. the 3600 may have come with this set up. you could remove a few leaves from the stock heavy set up and still have a comfortable ride if you keep the overloads. you could also install some air helper springs for those days when you haul something heavy. check here for a pic of the overload leaves and the air helper springs. available at a camper shop if you wanted to see them first hand

https://www.truckcampermagazine.com/...ft-suspension/

check here for a pic of what I mean about the overload springs.

http://chevy.oldcarmanualproject.com...esto/51128.htm

51 3600 · 03-20-2018, 08:52 PM

Good info here. Didn't think about interference with the running board bracket until whitedog mentioned it. Since old rear suspension is removed I hadn't paid attention to the spring hanger location. All springs I've looked at seem to be 52" and 56" long which would compromise the RB bracket. Judging by the loose fit of the spring clips, this truck at some point had additional leaves beyond stock 3600.
Dsraven's suggestion of custom modern spring and helper set up has merit. Get 1/2 ton ride for most of the time but 3/4 ton capacity when needed. By loaded I mean how you normally load a pickup (maybe occasionally more than one should as all do) not like Jed Clampet moving to Beverly Hills. Truck will have discs on all 4.
Haven't found a spring shop in Jacksonville yet although I've been told there is one.

03-17-2018, 09:23 PM	#1
51 3600 Registered User Join Date: May 2016 Location: Orange Park, FL Posts: 191	3600 rear leaf spring options? Been on this forum almost two years mostly lurking, learning and buying a few items from members. Getting to a point where I now have questions I haven't seen covered here or I've just missed them. This is my first AD truck (previous experiences with Karmann Ghias and Shovelheads) so a lot of ignorance behind my questions. I have a '51 3600 I'm trying to upgrade to use as a reliable, daily work truck. I flip houses so it needs to haul sheetrock, flooring, mulch, etc. So far truck is down to frame, unwanted items removed, frame blasted and painted, Blazer front suspension installed, Exploder 8.8 rearend with 3.73 diff & traction-lock ready to install, and 2001 Tahoe purchased for donor 5.3LS & 4L60e sitting in the wings. Keeping a leaf spring rear suspension but would like to update it with newer wider (2.5") leaf springs for better ride/handling but keep load capacity. Also was hoping to utilize the original spring hangers which I know are made for 1.75" springs but thought inner side of hanger could be welded up and then machined to accommodate the the wider leaf. And rather than have a custom spring made is there a vehicle out there that has a appropriate spring (2.5" wide x 47" long) that would work. I know square body 3/4 tons have the kind of setup I'm trying to mimic but springs are a lot longer. Any help and suggestions greatly appreciated. Al

03-19-2018, 07:49 AM	#2
ADchevys Registered User Join Date: Oct 2009 Location: Marysville KS Posts: 105	Re: 3600 rear leaf spring options? Just got done putting a Firebird reared under a 54 3600. We used early 80’s 1/2 ton c10 leaf springs and hangers. The hangers bolted to the side of the frame, we put the rearend on top of the leaf springs.

03-19-2018, 06:35 PM	#5
ADchevys Registered User Join Date: Oct 2009 Location: Marysville KS Posts: 105	Re: 3600 rear leaf spring options? What’s a good site to host pictures. We removed the back running board mount.

03-20-2018, 09:16 AM	#6
whitedog76 Registered User Join Date: Jan 2014 Location: Peoria, IL Posts: 1,450	Re: 3600 rear leaf spring options? If you have pics on your computer/tablet, you can upload them to this sight in the advanced settings.

03-20-2018, 09:51 AM	#7
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 7,824	Re: 3600 rear leaf spring options? before you go and install a bunch of heavy duty springs to haul around a heavy load, think about what you have for brakes to stop the heavy load. a stop by your local spring shop seems to be the next step. if doing this for a long time daily driver you would do yourself a favor if you simply get a set made to fit your truck. a new set of spring hangers may not be a bad idea to match up with some wider springs or, for a softer ride with no load, install some overload springs above your regular springs that contact some frame "slipper" brackets when the truck is loaded sufficiently. that way you ride on 1/2 ton springs until you get a heavy load, then the overload springs help out. still gotta be able to stop the whole thing though. the 3600 may have come with this set up. you could remove a few leaves from the stock heavy set up and still have a comfortable ride if you keep the overloads. you could also install some air helper springs for those days when you haul something heavy. check here for a pic of the overload leaves and the air helper springs. available at a camper shop if you wanted to see them first hand https://www.truckcampermagazine.com/...ft-suspension/ check here for a pic of what I mean about the overload springs. http://chevy.oldcarmanualproject.com...esto/51128.htm

03-20-2018, 08:52 PM	#8
51 3600 Registered User Join Date: May 2016 Location: Orange Park, FL Posts: 191	Re: 3600 rear leaf spring options? Good info here. Didn't think about interference with the running board bracket until whitedog mentioned it. Since old rear suspension is removed I hadn't paid attention to the spring hanger location. All springs I've looked at seem to be 52" and 56" long which would compromise the RB bracket. Judging by the loose fit of the spring clips, this truck at some point had additional leaves beyond stock 3600. Dsraven's suggestion of custom modern spring and helper set up has merit. Get 1/2 ton ride for most of the time but 3/4 ton capacity when needed. By loaded I mean how you normally load a pickup (maybe occasionally more than one should as all do) not like Jed Clampet moving to Beverly Hills. Truck will have discs on all 4. Haven't found a spring shop in Jacksonville yet although I've been told there is one.



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