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2” lift rear leafs

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jpnjim View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: May/27/2018 at 10:04am
Pulling one leaf out of a pack and running them like that is a good way to get a new set of springs to settle down.

Loading up extra weight helps too,
when I put the Metric Ton springs on the Comanche I drove to Home Depot and loaded up about 1000lbs of crushed gravel that I needed for a project.
A month or so driving like that settled them down 

^Not sure how that would work with the Gremmie,
so maybe pulling a leaf for a short time would work better.

Did you need longer shocks to make that work?
71 Javelin AMX P-code Go pac 360/4spd/3.91's
was Green/green now T/A red w/blk leather

88,89&98 Jeeps
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Post Options Post Options   Thanks (0) Thanks(0)   Quote knobbler Quote  Post ReplyReply Direct Link To This Post Posted: Jun/01/2018 at 6:48pm
I somehow managed to miss this thread until just now. I'm having the same problem with my '78, though my leaf packs are supposed to match a stock ride height (as best as I can tell, anyway). If you don't mind my asking, I have a couple questions:

What are your measurements, eye-to-center and depth of arch for your lift springs?

What year is your Gremlin?

When you installed the longer shackles, did you use the old leaf packs, or the new ones?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jun/03/2018 at 11:39am
It sounds like the leafs were arched more, but not lengthened to make up for the extra arch. Until they take a set ("settle down") taking a leaf out might help. 
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gelalthedamned Quote  Post ReplyReply Direct Link To This Post Posted: Jun/04/2018 at 3:45pm
Originally posted by farna farna wrote:

but not lengthened to make up for the extra arch


I think so too.
Was talking to knobbler about it the other day.
My measurements are
A&b are 23” ...that’s stock specs
C is 8” (6something is stock height..the extra 2 would be my lift?)
D is 1 1/8 which is correct for the 5 leaf
What I think was miscalculated was what I termed e (distance from mount to mount)
Rough measurements on the vehicle is 46 1/2”
The new springs at rest on their sides measured 41”
Calamity - 73 Gremlin X zombie rod (daily driver)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Jun/04/2018 at 7:08pm
There are a number of different leaf springs for Gremlin shown in the SRI (Spring Research Institute) listings I have:

67-469, 1970-76 Gremlin 6-8 cyl auto trans, 1-1/2" Front Eye, 4 leaf, 23"/23", 6-7/8" Arch (4488444, 8123392, 8125896)

64-471, 1970-76 Gremlin 6-8 cyl auto trans HD, 1-1/2" Front Eye, 5 leaf, 23"/23", 6-1/4"-6-1/2" Arch (4488494, 8123393)

67-487, 1971-73 Gremlin 6 cyl std trans, 2" Front Eye, 23"/23", 4 leaf, 7" Arch (8120290, 8120490)

67-489, 1971-72 Gremlin 6 cyl std trans HD, 2" Front Eye, 5 leaf, 23"/23", 6-3/8" Arch (8120291, 8120491)

But then the numbers really change for the 1977 models:

67-519, 1977 Gremlin 4 cyl, stamped 010HB, 4 leaf, 23"/23", 8-1/4" Arch (3231010)

67-521, 1977 Gremlin 4 cyl HD, stamped 011HC, 4 leaf, 23"/23", 8-3/4" Arch (3231011)

67-539, 1977 Gremlin 6 cyl, stamped 868QC, 4 leaf, 23"/23", 8-1/4" Arch (3226868)

67-523, 1977 Gremlin 6 cyl HD, stamped 312QD, 4 leaf, 23"/23", 8-3/4" Arch (3229312)

And then the 1978 models:

67-545, 1978 Gremlin 4 cyl, stamped 210HA, 4 leaf, 23"/23", 7-3/4" Arch (3232210)

67-519, 1978 Gremlin 6 cyl, stamped 010HB, 4 leaf, 23"/23", 8-1/4" Arch (3231010)

67-521, 1978 Gremlin, HD, stamped 011HC, 4 leaf, 23"/23", 8-3/4" Arch (3231011)

With about 2-1/2" more arch on the 1978 HD spring over the 1972 HD spring, and typical average spring rates around 100 lb/inch, the 1978-79 cars would have to be 500 lbs heavier in the back end in order to have the same ride height as earlier models. Something isn't adding up here.
Chris ("Mojo")
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Post Options Post Options   Thanks (0) Thanks(0)   Quote knobbler Quote  Post ReplyReply Direct Link To This Post Posted: Jun/05/2018 at 4:06am
Originally posted by Greyhounds_AMX Greyhounds_AMX wrote:


Awesomely useful info


Thanks a million for posting those details! That explains why I was fighting so hard with the leaf packs I bought from SD truck springs - they had the SRI number on the product page, but it didn't mention they were HD springs. That really clears things up!

About the change in '77: Iso-clamp axles started being used in '77 (but only with certain options, if I understand correctly), so I wonder if the additional arch was introduced to accommodate the additional concentration of weight to the center of the leaf packs that is supposed to be an effect of the iso-clamp design? Aside from the iso axle and it's components, there's little to no difference in the rear end of my '78 in comparison to earlier years (at least that I've noticed). I haven't dug much deeper yet, but Eaton's site lists different part numbers for the front coils for a '73 with a 258 than it does for the '78. I wonder if there is a corresponding change in the front springs to coincide with the change in '77 with the leafs.

Regardless, I agree that something doesn't seem quite right if there's a 5-1/2" difference in spread between the new and old leafs. Even when accounting for the increased arch of the new and wear of the old springs, that seems like a pretty dramatic difference.

Just so we can get a better idea of what numbers we're looking at, which engine/trans type is your Gremlin? Could you have possibly got leaves that were intended for a different combination? Also, does Eaton say what the direct eye-to-eye measurement should be for that part number? If not, it might be worth giving them a call to verify.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gelalthedamned Quote  Post ReplyReply Direct Link To This Post Posted: Jun/05/2018 at 8:47am
Sent Eaton my measurements..got this 3 minutes ago
Calamity - 73 Gremlin X zombie rod (daily driver)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gelalthedamned Quote  Post ReplyReply Direct Link To This Post Posted: Jun/05/2018 at 8:52am
Sri stock specs for my application would be
64-471, 1970-76 Gremlin 6-8 cyl auto trans HD, 1-1/2" Front Eye, 5 leaf, 23"/23", 6-1/4"-6-1/2" Arch (4488494, 8123393)

I’m kinda dumb...but, Eaton May be dumb too
Cause this is agrivating.

The “remove a leaf” theory for getting them up in there.. which leaf?
Calamity - 73 Gremlin X zombie rod (daily driver)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jun/06/2018 at 7:02am
Based on what Eaton says, you will need to move the shackle forward a bit to maintain the lift and have the spring operate correctly. I suspected as much. You might want to replace the shackles with sliders.

Removing a leaf may work, but you will have a weaker spring, and could lose some of the lift you wanted. Certainly will for a time while the leafs "settle down". I'd think you would want to remove one of the lower leafs (bottom leaf). The lower, shorter leafs add stiffness. I'd move the shackle mount forward an inch or two or use a slider though.
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gelalthedamned Quote  Post ReplyReply Direct Link To This Post Posted: Jun/06/2018 at 1:35pm
It’ll be a couple of weeks, cause all the bills happen at the beginning of the month.
Slider shackles will likely happen, but the hd bearing set cause it has more bolt locations for finding the sweet spot and amx shock mounts to compensate the lift vs Gremlin plates and some nasty new shocks.
Also it’s in my brain to trade out a few of the new leafs with my older stock leafs just to see if that’ll make it fit without further mods. Cause that pinion angle was way pitched when I first put those springs in.

-and all this just because I want my rear fatties to have that “tonka” look
Calamity - 73 Gremlin X zombie rod (daily driver)
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