I know we already discussed this, but... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Kiss My SS · 12-03-2002, 05:53 PM

OK, so I know in a previous post I asked about 3/4 ton axles and such out of a mid '70s truck for my '72 Jimmy. Well, what I am still confused about is the 3/4 ton springs. What I need to know is, will the 3/4 springs go in as a direct replacement for my 1/2 ton springs? Are the 72 1/2ton and mid 70's 3/4 ton spring the same length? I was hoping to at least upgrade the suspension for now and the axles at a later time. (money is tight for a college student with 4 vehicles)

Also, I posted previously that I couldn't get my 205 t/c to engage. Well, I figured out what was wrong. The shifter and linkages weren't tight so it wasn't engaging the front shaft. Some grease and a few turns of the wrench got that taken care of. On the the next problem. The hubs were locked and the front shaft turning, but alas, not wheels were turning. Well, I popped off the hubs only to find that they were full of rust, dirt and little grease. 2 solid days of work and $200 later the front axle was completely rebuilt with new bearings, seals and lots of fresh grease. 4x4 now works. That is one reason why I want to keep the old axles for now. I just figure that the heavier springs will fix the gimpy stance that my truck has.

Scrub · 12-03-2002, 11:57 PM

When you order a lift kit, they always ask you to go measure the rear springs. Some are longer and I don't know why, but i don't think it is a 1/2 vs 3/4 ton thing.

Anyway, just measure your springs and find the same size.

good luck

Pont · 12-04-2002, 09:24 AM

The only difference in spring length that I'm aware of is 67-68 truck rear springs being 56" long from eye bolt to eye bolt and the axle centering pin is dead center. The 69-newer are 52" eye bolt to eye bolt and the axle centering pin is offset. The front springs have the same dimensions on all years. Hope this helps.....

Mike C · 12-04-2002, 10:31 AM

Most of the 73 and up 3.4 ton springs are 52" eye to eye, but some are 56". I have a set of 56" 4" lift springs that came off a '76 Blazer parts truck I had and was told they were re-arched 3/4 tons from a '74 truck. They could be used if you were willing to relocate the rear perch. I have 52" 3/4 ton National 4" lift springs on my Jimmy. If it was my money (and it was, after bending spring perches with cast iron blocks) I would buy aftermarket lift springs and not monkey with blocks or add-a-leaves. Obviously if you are needing 3/4 ton axles you want big tires and that means a lift.

ozarkhippie · 12-04-2002, 01:41 PM

To the best of my knowlege the front springs on 73 up are longer than those on 72 down 4x4's.

69custom4x · 12-04-2002, 08:26 PM

ozarkhippie is correct on this one. I took the springs from a 78 chevy and put them in my 69. I had to relocate the rear hanger on the front springs otherwise the shackles would hit on the frame. Made for an extremely stiff ride.

12-03-2002, 05:53 PM	#1
Kiss My SS Registered User Join Date: Nov 2002 Location: Omaha/Grand Island, NE Posts: 229	I know we already discussed this, but... OK, so I know in a previous post I asked about 3/4 ton axles and such out of a mid '70s truck for my '72 Jimmy. Well, what I am still confused about is the 3/4 ton springs. What I need to know is, will the 3/4 springs go in as a direct replacement for my 1/2 ton springs? Are the 72 1/2ton and mid 70's 3/4 ton spring the same length? I was hoping to at least upgrade the suspension for now and the axles at a later time. (money is tight for a college student with 4 vehicles) Also, I posted previously that I couldn't get my 205 t/c to engage. Well, I figured out what was wrong. The shifter and linkages weren't tight so it wasn't engaging the front shaft. Some grease and a few turns of the wrench got that taken care of. On the the next problem. The hubs were locked and the front shaft turning, but alas, not wheels were turning. Well, I popped off the hubs only to find that they were full of rust, dirt and little grease. 2 solid days of work and $200 later the front axle was completely rebuilt with new bearings, seals and lots of fresh grease. 4x4 now works. That is one reason why I want to keep the old axles for now. I just figure that the heavier springs will fix the gimpy stance that my truck has. __________________ 1972 GMC Jimmy 4x4 1985 Chevy Monte Carlo SS 1996 Saturn SC-2 1996 Ford Explorer XLT -Wife's rig

12-03-2002, 11:57 PM	#2
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	When you order a lift kit, they always ask you to go measure the rear springs. Some are longer and I don't know why, but i don't think it is a 1/2 vs 3/4 ton thing. Anyway, just measure your springs and find the same size. good luck __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-04-2002, 09:24 AM	#3
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	The only difference in spring length that I'm aware of is 67-68 truck rear springs being 56" long from eye bolt to eye bolt and the axle centering pin is dead center. The 69-newer are 52" eye bolt to eye bolt and the axle centering pin is offset. The front springs have the same dimensions on all years. Hope this helps..... __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness" Last edited by Pont; 12-04-2002 at 10:26 AM.

12-04-2002, 10:31 AM	#4
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Most of the 73 and up 3.4 ton springs are 52" eye to eye, but some are 56". I have a set of 56" 4" lift springs that came off a '76 Blazer parts truck I had and was told they were re-arched 3/4 tons from a '74 truck. They could be used if you were willing to relocate the rear perch. I have 52" 3/4 ton National 4" lift springs on my Jimmy. If it was my money (and it was, after bending spring perches with cast iron blocks) I would buy aftermarket lift springs and not monkey with blocks or add-a-leaves. Obviously if you are needing 3/4 ton axles you want big tires and that means a lift. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

12-04-2002, 01:41 PM	#5
ozarkhippie Registered User Join Date: Nov 2002 Location: Eureka Springs AR Posts: 494	To the best of my knowlege the front springs on 73 up are longer than those on 72 down 4x4's. __________________ Buy Sale or Trade 71 3/4 4x4 72 1/2 ton cheyenne 4x4

12-04-2002, 08:26 PM	#6
69custom4x Registered User Join Date: Oct 2002 Location: Albuquerque, NM Posts: 24	ozarkhippie is correct on this one. I took the springs from a 78 chevy and put them in my 69. I had to relocate the rear hanger on the front springs otherwise the shackles would hit on the frame. Made for an extremely stiff ride.



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