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Coil spring swap... updated with results #1903356
08/31/15 07:02 PM
08/31/15 07:02 PM
Joined: Dec 2005
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Bowling Green KY / Nashville, ...
300by500 Offline OP
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I'm lowering my '84 D350 Crew- not ground-scraping low, just enough that it doesn't look stock. I already modified the rear spring hanger to lower the rear about 2 to 2-1/2 inches, and I plan on relocating the front hanger for an additional inch.

On the front springs I've been doing some investigating.
The Moog stock HD D350 spring shows these specs:
.90 bar diameter / 13.13 installed height / 1725 lbs / 1144lbs-inch.
The Moog #7170 stock D250 spring shows these specs:
.810 bar diameter / 10.5 installed height / 1815 lbs / 845 lbs-inch.

From these measurements I''m assuming I'll get a more comfortable ride, and I should end up with just over 2-1/2 inch drop just from the difference in installed height (my D350 has pocketed lower control arms), and approximately one more inch additional drop due to the difference in spring rate, for a total of about 3-1/2 inches.

I don't have much experience with this sort of thing, and just thought I would get opinions from folks who may have done something similar. Weird that the total capacity of each D250 spring is rated 90 lbs. higher than each D350 spring...

Last edited by 300by500; 09/15/15 11:21 AM.
Re: Coil spring swap opinions... [Re: 300by500] #1904694
09/02/15 05:10 AM
09/02/15 05:10 AM
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Back home in PA
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BulletBob Offline
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I moved the hangers up on the frame in the rear & cut a coil and a half in the front
Rode fine no problems
I used a 31" tire in the rear & a 29" tire in the front to level it plus the 31" tire killed some of the 4.10's My OD did the rest

Re: Coil spring swap opinions... [Re: 300by500] #1904732
09/02/15 10:21 AM
09/02/15 10:21 AM
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Bowling Green KY / Nashville, ...
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Thanks Bob!

I also went for a little stagger on the tires, 245s front and 265s rear.

I already ordered those D250 springs, Jegs had them for $72 a pair with free shipping. I'll keep the old ones in case I ever want to take it back to stock. I should be able to use a stock replacement D250 shock and maintain ride quality just as good as an OEM set up... hopefully.

I'll let you know how it turns out!

Re: Coil spring swap opinions... [Re: 300by500] #1905519
09/03/15 05:35 AM
09/03/15 05:35 AM
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Back home in PA
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BulletBob Offline
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Which D250 did you order them for? There are two different heights

Re: Coil spring swap opinions... [Re: 300by500] #1905548
09/03/15 09:59 AM
09/03/15 09:59 AM
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The shorter one. It should basically have the same effect as installing a pocketed lower control arm on a half ton, or on a 3/4 ton without the 4000 lb front end.

Re: Coil spring swap opinions... [Re: 300by500] #1905846
09/03/15 07:45 PM
09/03/15 07:45 PM
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Joplin, MO USA
Robbins Offline
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Cool stuff....thanks for sharing. Hey......please post pictures....

Last edited by Robbins; 09/04/15 12:29 AM.

Moparlee
Re: Coil spring swap opinions... [Re: Robbins] #1912899
09/15/15 11:36 AM
09/15/15 11:36 AM
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Bowling Green KY / Nashville, ...
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Okay, for better or worse - this is what happened.

Here are the new and old coil side-by-side....



The result was a little more drop than I anticipated. When I finished it was resting on the bump stops. I trimmed them an inch and it was no longer resting on them. I like the look, but for all practical purposes it is a little too low.



I have two options now - First I'm gonna try a spring rubber to raise it 1 to 1-1/2" and I'll see if the ride is decent. If that doesn't work I'll cut the stock springs and reinstall them.



Could be that my truck squatted more than a single-cab D350 would have. I'm sure the bigger frame and extra weight of the cab adds quite a few pounds.

I guess life is a learning experience - sometimes we learn what NOT to do! LOL! Just thought I'd let everyone know how it turned out.

Re: Coil spring swap opinions... [Re: 300by500] #1912923
09/15/15 11:58 AM
09/15/15 11:58 AM
Joined: May 2003
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Florida
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just so you know..if you put that d350 spring in a 1/2 ton NON-pocket LCA you get lift and rest on the rubber bumpers with control arms at full droop. opposite your drop..LOL!

I drove the stepside off road like that about a yr, then noticed it ripping the LCA mount off the rivits/frame.

you could get a non-pocket LCA arm with that new 1/2 ton spring to gain a inch or so back maybe. the weight is going to help level it out with this idea.

Re: Coil spring swap opinions... [Re: 300by500] #1912982
09/15/15 01:26 PM
09/15/15 01:26 PM
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Pretty sure I'm just going to cut a coil out of the old springs, and reinstall them along with D350 shocks.

If anyone needs a brand new set of D250 non-pocket LCA coil springs and shocks, PM me and I'll make you a good deal! LOL!

Last edited by 300by500; 09/15/15 05:06 PM.
Re: Coil spring swap opinions... [Re: 300by500] #1913194
09/15/15 07:20 PM
09/15/15 07:20 PM
Joined: Jun 2004
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NW PA
V10nacuda Offline
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Ya might want to start at 1/2 coil and check ride height.. my bro got carried away and found out u cant add spring back!

My 02cents
V10

Re: Coil spring swap opinions... [Re: 300by500] #1913363
09/15/15 11:08 PM
09/15/15 11:08 PM
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Lehigh Acres, Florida
rickstershemi Offline
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FWIW it sits like our old D100 which ended up with less than an inch of clearance once we cut the bump stops down and it rode and drove awesome once aligned properly smile

Rickster

Re: Coil spring swap opinions... [Re: 300by500] #1913595
09/16/15 12:09 PM
09/16/15 12:09 PM
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Bowling Green KY / Nashville, ...
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I only trimmed about an inch from the bump stops - you removed yours completely?

Re: Coil spring swap opinions... [Re: 300by500] #1917021
09/21/15 09:28 PM
09/21/15 09:28 PM
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North, Alabama
D-50 Offline
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When you cut a coil does it make the spring rate stiffer or is it the same as before. The reason I ask is I have a D50 with a V8 that I want to lower some in the front and it also needs to be a little stiffer. I have not seen any springs except stock.

Last edited by D-50; 09/21/15 09:29 PM.

1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
Re: Coil spring swap opinions... [Re: D-50] #1917370
09/22/15 01:32 PM
09/22/15 01:32 PM
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Cutting active coils on a coil spring increases the spring rate. Think of a coil spring as a torsion bar that's been wrapped around a cylinder.

R.

Re: Coil spring swap opinions... [Re: dogdays] #1919104
09/24/15 10:10 PM
09/24/15 10:10 PM
Joined: Oct 2009
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North, Alabama
D-50 Offline
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Originally Posted By dogdays
Cutting active coils on a coil spring increases the spring rate. Think of a coil spring as a torsion bar that's been wrapped around a cylinder.

R.

Does that mean that if I cut maybe a half a coil off it will lower it and be a little stiffer in the front also ?


1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
Re: Coil spring swap opinions... [Re: 300by500] #1919199
09/24/15 11:48 PM
09/24/15 11:48 PM
Joined: May 2003
Posts: 1,722
Chicagoland
Cooter Offline
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Yes

Re: Coil spring swap opinions... updated - done! [Re: Cooter] #1919258
09/25/15 01:54 AM
09/25/15 01:54 AM
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Well, I took the light-duty D250 stuff out and cut my D350 springs 1-1/4 coils. It was STILL too low! So I got another used set of D350 coils, cut them 3/4 of a coil, and ended up right where I wanted it to be.

The bottom pic was last summer, top pic was tonight. With the relocated rear leaf shackle mount I ended up about 3" lower, front and rear. I also swapped on the brackets and new later-model bumper today. wrench

Ride doesn't seem much different, it ain't no New Yorker! LOL!


Re: Coil spring swap opinions... updated - done! [Re: 300by500] #1919280
09/25/15 03:57 AM
09/25/15 03:57 AM
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Marysville, WA
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I like it!

Re: Coil spring swap opinions... updated - done! [Re: 300by500] #1919317
09/25/15 09:48 AM
09/25/15 09:48 AM
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Pennsylvania
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That is a good lookin truck. I like the ride height.

Re: Coil spring swap opinions... updated - done! [Re: 300by500] #1921244
09/28/15 03:38 PM
09/28/15 03:38 PM
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Joplin, MO USA
Robbins Offline
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Awesome


Moparlee
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