GMC leaf spring lowering - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GreenAcres · 03-10-2010, 10:50 AM

Doh!...already committed to buy a '68 1/2T, SWB GMC.

How do you lower a leaf spring rear suspension? (I realize converting to coil spring gives more options...let's skip that part for now please)

How much drop is possible? Any photos, or links?

(note planned on a drop spindle front)

Thanks,
John

Orange · 03-10-2010, 11:03 AM

There are really 2 common options.
First is the cheapest which is to flip the rear end...that is put the springs on the other side of the axle.
http://www.stylintrucks.com/parts.as...tfamilyid=3339

The other most common option (what I did) was the Early Classic lowering leaf's.
http://www.earlyclassic.com/catalog.aspx (Go to Leaf Springs and Rear Shackles).
Coupled with their drop shackles you can get 5.5" drop.

I have to get some better pics of mine, but here's one that shows it pretty good:

(full size is at slickorange.com - which is out of date...been busy lately.)

That's static with 3" CPP springs and the ECE rear drop leaf's @ 4".

DLB

Ackattack · 03-10-2010, 11:30 AM

I removed leafs from my 72 GMC (that's really cheap!). I did have wheel hop problems when I was at the track (broke a u-joint).

GreenAcres · 03-10-2010, 11:38 AM

Thanks DLB,

Great links. (I obviously didn't have the patience to find the right parts on the ECE site).

Next question...can I expect the same results as if using 6" lowering coils? That is, no interfence with the frame? no need to notch?

And would like to see more examples (thanks again) to see what the option combinations are.

John

butternut1972 · 03-10-2010, 11:47 AM

I used a bell tech flip kit on mine and a de-arched spring. It did require a c-notch. The ride is pretty good.

dieselarmy13 · 03-10-2010, 12:05 PM

I used the flip kit and removed a couple of leafs. Pics in my build thread down below.

GreenAcres · 03-10-2010, 12:45 PM

Thanks Gentlemen...more great links!

Anyone else? "To notch?...or not to notch?"

chevydog66 · 03-10-2010, 10:56 PM

I did some drop shackles from styin concepts and then removed that top leaf. It dropped about 4". O ya, and try to search the Suspension section.

dieselarmy13 · 03-11-2010, 03:21 AM

You will need a notch

slow72 · 03-11-2010, 05:19 AM

I used a flip kit from DJM. Dropped the rear almost 6 inches. Afterwards it was evident that a notch was required since my axle was less than an inch away from my frame. For now i have avoided notching by adding helper airbags on top of the leafs. I will be switching to a coil frame and full air ride setup this summer with a bolt in notch.

CHEMPOWR · 03-11-2010, 08:26 AM

I have a flip kit with lowering shackles and it is notched. Check out my avatar and profile for pics. I can't figure out how to post pics to my reply yet.

I think you will need to notch the frame if you lower more than 4 inches I believe.

Jeffs70 · 03-11-2010, 08:58 AM

Quote:

Originally Posted by GreenAcres

Thanks DLB,

Great links. (I obviously didn't have the patience to find the right parts on the ECE site).

Next question...can I expect the same results as if using 6" lowering coils? That is, no interfence with the frame? no need to notch?

And would like to see more examples (thanks again) to see what the option combinations are.

John

I have non arched leafs and axle on top with a leaf removed and a C-notch on one of my trucks there is no way of getting away from a Notch I do not believe at how low you have specified you wish to go.

Even with rear Coil's at a 6" drop you will still need to notch the frame

GreenAcres · 03-11-2010, 09:19 AM

Quote:

Originally Posted by Jeffs70

... I do not believe at how low you have specified you wish to go.

Even with rear Coil's at a 6" drop you will still need to notch the frame

Jeffs70,

My thoughts for spec's are:
Drop Front with 2 1/2" spindles and 1" lowering springs.
Drop Rear is my question mark. Level would be ideal, but slightly higher (subjective...I know) is OK.

This is why these links to photos and others specs are FANTASTIC, and slow72, just the kind of info I was looking for.

Like I stated earlier, didn't want to go the route of discussing pros/cons of a coil swap.

Orange · 03-11-2010, 09:53 AM

FWIW I didn't have to notch (axle didn't "relocate") and I can swap back to original just by changing out my springs. That's something to consider if you don't want to cut on your truck. Most guys though that commit to a suspension change don't mind that.

I just wanted the ability to go back if I ever wanted too...and if gassers are the new craze again in 2020, I'll be one step ahead.

DLB

03-10-2010, 10:50 AM	#1
GreenAcres "I tawt I taw a puddy tat!" Join Date: Feb 2010 Location: KC Posts: 109	GMC leaf spring lowering Doh!...already committed to buy a '68 1/2T, SWB GMC. How do you lower a leaf spring rear suspension? (I realize converting to coil spring gives more options...let's skip that part for now please) How much drop is possible? Any photos, or links? (note planned on a drop spindle front) Thanks, John __________________ '67 C/20 LWB CST 283/SM420 FleetWood - project "HELL!" '68 GMC 1500 SWB Fleetside 250/TOT SOLD '70 C/10 454/TH400 LWB SOLD

03-10-2010, 11:03 AM	#2
Orange Licensed to Thrill! Join Date: Apr 2006 Location: Northwest, GA Posts: 1,673	Re: GMC leaf spring lowering There are really 2 common options. First is the cheapest which is to flip the rear end...that is put the springs on the other side of the axle. http://www.stylintrucks.com/parts.as...tfamilyid=3339 The other most common option (what I did) was the Early Classic lowering leaf's. http://www.earlyclassic.com/catalog.aspx (Go to Leaf Springs and Rear Shackles). Coupled with their drop shackles you can get 5.5" drop. I have to get some better pics of mine, but here's one that shows it pretty good: (full size is at slickorange.com - which is out of date...been busy lately.) That's static with 3" CPP springs and the ECE rear drop leaf's @ 4". DLB __________________ 1971 GMC.Lowered. Overdrive. Orange. Krue's excellent FAQ Index. Last edited by Orange; 03-10-2010 at 11:04 AM.

03-10-2010, 11:30 AM	#3
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,525	Re: GMC leaf spring lowering I removed leafs from my 72 GMC (that's really cheap!). I did have wheel hop problems when I was at the track (broke a u-joint). __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

03-10-2010, 11:38 AM	#4
GreenAcres "I tawt I taw a puddy tat!" Join Date: Feb 2010 Location: KC Posts: 109	Re: GMC leaf spring lowering Thanks DLB, Great links. (I obviously didn't have the patience to find the right parts on the ECE site). Next question...can I expect the same results as if using 6" lowering coils? That is, no interfence with the frame? no need to notch? And would like to see more examples (thanks again) to see what the option combinations are. John __________________ '67 C/20 LWB CST 283/SM420 FleetWood - project "HELL!" '68 GMC 1500 SWB Fleetside 250/TOT SOLD '70 C/10 454/TH400 LWB SOLD

03-10-2010, 11:47 AM	#5
butternut1972 Registered User Join Date: May 2009 Location: longview,wa Posts: 1,094	Re: GMC leaf spring lowering I used a bell tech flip kit on mine and a de-arched spring. It did require a c-notch. The ride is pretty good. Attached Images

03-10-2010, 12:05 PM	#6
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Re: GMC leaf spring lowering I used the flip kit and removed a couple of leafs. Pics in my build thread down below. __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

03-10-2010, 12:45 PM	#7
GreenAcres "I tawt I taw a puddy tat!" Join Date: Feb 2010 Location: KC Posts: 109	Re: GMC leaf spring lowering Thanks Gentlemen...more great links! Anyone else? "To notch?...or not to notch?" __________________ '67 C/20 LWB CST 283/SM420 FleetWood - project "HELL!" '68 GMC 1500 SWB Fleetside 250/TOT SOLD '70 C/10 454/TH400 LWB SOLD

03-10-2010, 10:56 PM	#8
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: GMC leaf spring lowering I did some drop shackles from styin concepts and then removed that top leaf. It dropped about 4". O ya, and try to search the Suspension section. __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up Last edited by chevydog66; 03-10-2010 at 10:57 PM.

03-11-2010, 03:21 AM	#9
dieselarmy13 Phone's ringin Dude. Join Date: Mar 2007 Location: Colorado Springs Posts: 1,426	Re: GMC leaf spring lowering You will need a notch __________________ I pitty the fool with only two headlights!! 2003 SILVERADO SS--THE NEW GIRL 1972 GMC--THE OLD GIRL

03-11-2010, 05:19 AM	#10
slow72 Registered User Join Date: Sep 2008 Location: Regina, Saskatchewan Posts: 43	Re: GMC leaf spring lowering I used a flip kit from DJM. Dropped the rear almost 6 inches. Afterwards it was evident that a notch was required since my axle was less than an inch away from my frame. For now i have avoided notching by adding helper airbags on top of the leafs. I will be switching to a coil frame and full air ride setup this summer with a bolt in notch. __________________ 1972 GMC LWB, 250, 4sp 2010 GMC Sierra 6.6 CCSB Last edited by slow72; 03-11-2010 at 05:20 AM.

03-11-2010, 08:26 AM	#11
CHEMPOWR Registered User Join Date: Jul 2009 Location: Beyond, TX Posts: 61	Re: GMC leaf spring lowering I have a flip kit with lowering shackles and it is notched. Check out my avatar and profile for pics. I can't figure out how to post pics to my reply yet. I think you will need to notch the frame if you lower more than 4 inches I believe. __________________ 1969 GMC Wideside SWB 400ci/TH400/373/Disc Brakes/Leaf Springs 1992 Chevy C3500 Ext Cab Dually Silverado 454 TBI 2007 Chevy Corvette ZO6 427ci 505HP Last edited by CHEMPOWR; 03-11-2010 at 08:29 AM.

03-11-2010, 09:53 AM	#14
Orange Licensed to Thrill! Join Date: Apr 2006 Location: Northwest, GA Posts: 1,673	Re: GMC leaf spring lowering FWIW I didn't have to notch (axle didn't "relocate") and I can swap back to original just by changing out my springs. That's something to consider if you don't want to cut on your truck. Most guys though that commit to a suspension change don't mind that. I just wanted the ability to go back if I ever wanted too...and if gassers are the new craze again in 2020, I'll be one step ahead. DLB __________________ 1971 GMC.Lowered. Overdrive. Orange. Krue's excellent FAQ Index.



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