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2” lift rear leafs

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Suspension, Steering, Brakes & Wheels
Forum Description: What makes it stop, turn, and smooths the ride
URL: https://theamcforum.com/forum/forum_posts.asp?TID=94351
Printed Date: Mar/28/2024 at 4:18pm
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Topic: 2” lift rear leafs
Posted By: Gelalthedamned
Subject: 2” lift rear leafs
Date Posted: May/25/2018 at 8:06am
Bought a set of 2” lifted leaf springs for my Gremlin from Eaton Detroit.
Put them in...and this is happening.
What’s that about?

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Calamity - 73 Gremlin X zombie rod (daily driver)



Replies:
Posted By: 2Busy
Date Posted: May/25/2018 at 9:01am
Are they too short in length? How do they compare in length to the original ones?


Posted By: 73hornut
Date Posted: May/25/2018 at 9:35am
Not real happy with eaton springs. I recently bought new front springs for my gremlin, 1-1/2in lower, for v8, still sits at stock ride height, same as old 6cyl springs.

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71 Javelin
74 Gremlin
79 Spirit AMX
Rogue Valley Rumblers
Like Us on FB
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Posted By: gremlinsteve
Date Posted: May/25/2018 at 1:42pm
There too short in length from eye to eye


Posted By: Gelalthedamned
Date Posted: May/25/2018 at 4:58pm
Stock springs on the ground measure @43”...new ones are @43” on car with vehicle weight on them.

Eaton lady sent me this- ‘With a lifted spring, it’s a little more work to get those shackles in the correct position. Take some of the weight off the springs, using a pry/crow bar as the weight is let back down, move the shackles so they are pointing towards the rear of the car.‘
*im pretty dumb, what do you think ‘takes weight off springs’ mean? Lift car onto frame stands and unfasten axle?



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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Gelalthedamned
Date Posted: May/25/2018 at 5:08pm
rear fatties on stock springs had @1” gap from fender lip (that would contact the wheels over speed bumps and road dips)

new ones have a 5” gap (that’s way too much)

Ideas on how to lessen the arch at home?
No dice find a shop to do it?

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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: 73hornut
Date Posted: May/25/2018 at 9:50pm
Stock 5 leaf springs from Mcviegh on ebay, would have given you the ride height you desired.



-------------
71 Javelin
74 Gremlin
79 Spirit AMX
Rogue Valley Rumblers
Like Us on FB
https://www.facebook.com/groups/1602825606650796" rel="nofollow - https://www.facebook.com/groups/1602825606650796


Posted By: farna
Date Posted: May/26/2018 at 10:19am
The shackle mounts appear to bolt on. You could move the mount forward on the "frame". I'd use a set of sliders and eliminate the shackles -- problem solved!
http://www.speedwaymotors.com/Speedway-Standard-Leaf-Spring-Sliders,2151.html?sku=91043302&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=CjwKCAjwi6TYBRAYEiwAOeH7GW6HcSUYOlN-uNGf9PTZOZnpYLgDzUUcbhasnVb6SlFu-CgtVffn-BoCyXEQAvD_BwE" rel="nofollow - https://www.speedwaymotors.com/Speedway-Standard-Leaf-Spring-Sliders,2151.html?sku=91043302&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=CjwKCAjwi6TYBRAYEiwAOeH7GW6HcSUYOlN-uNGf9PTZOZnpYLgDzUUcbhasnVb6SlFu-CgtVffn-BoCyXEQAvD_BwE


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Frank Swygert


Posted By: Gelalthedamned
Date Posted: May/26/2018 at 10:31am
Originally posted by farna farna wrote:

move the mount forward on the "frame". use a set of sliders
sliders are likely a good idea, maybe even the boomerang shaped shackles.
I took one back off and measured it to a stock pack...it’s 3” shorter eye length.
They literally need de-arched a bit, so they’re going into the parts room till I get’em flattened out a bit.

In the meantime... plan b: low-brow shackle lift

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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Greyhounds_AMX
Date Posted: May/27/2018 at 8:22am
Nice job on the shackles. That block spacer is a great feature.

If i could add though based on my experience, the shackle shouldn't pinch the bushing much at all or it stiffens the ride. You could use a double nut arrangement on the inside there in order to set the squeeze just right and lock it in place. The stock stuff always has a shoulder bolt to set the width and prevent over compressing the bushing.

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1968 AMX 390 w/T5


Posted By: jpnjim
Date Posted: May/27/2018 at 9:04am
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?


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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords


Posted By: knobbler
Date Posted: Jun/01/2018 at 5:48pm
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?


Posted By: farna
Date Posted: Jun/03/2018 at 10:39am
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. 

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Frank Swygert


Posted By: Gelalthedamned
Date Posted: Jun/04/2018 at 2:45pm
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”


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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Greyhounds_AMX
Date Posted: Jun/04/2018 at 6:08pm
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.


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1968 AMX 390 w/T5


Posted By: knobbler
Date Posted: Jun/05/2018 at 3:06am
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.


Posted By: Gelalthedamned
Date Posted: Jun/05/2018 at 7:47am
Sent Eaton my measurements..got this 3 minutes ago

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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Gelalthedamned
Date Posted: Jun/05/2018 at 7:52am
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?

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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: farna
Date Posted: Jun/06/2018 at 6:02am
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.


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Frank Swygert


Posted By: Gelalthedamned
Date Posted: Jun/06/2018 at 12:35pm
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

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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Gelalthedamned
Date Posted: Jun/06/2018 at 12:41pm


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Calamity - 73 Gremlin X zombie rod (daily driver)


Posted By: Greyhounds_AMX
Date Posted: Jun/06/2018 at 1:04pm
I think on any normal vehicle a 2" lifted spring could use the standard main leaf with no worries. Yes, the geometry at the shackle would be off just a little, but not too bad.

But when you take a Gremlin leaf spring that's 6" shorter than everything else on the planet and arch it 2" more than stock the spring eyes move toward each other quite a bit. Using a boomerang shackle doesn't solve the big problem, which is this:

With the shackle angled all the way forward, when you go over a pothole or dip there's no way for the wheel to go down. In order for it to travel down, the spring arch has to increase, and for that to happen the two eyes have to get closer together. But in your case they can't so the wheel can't stay on the ground, which is bad of course.

A boomerang shaped shackle will make it look better, but won't actually change the geometry at all. 

The good news is that's it's not too hard to change the arch on springs at home if you have a press. For about $125 at HF and a little welded jig I can show you how to do it.


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1968 AMX 390 w/T5


Posted By: knobbler
Date Posted: Jun/06/2018 at 11:41pm
I'm a little disappointed in Eaton's reply, to be honest. I wouldn't describe spreading the eyes up to 5-1/2" just to get them to fit as only being "more difficult then a stock spring." At least they confirmed that the main leaf isn't lengthened to account for the lift (though some details as to WHY they don't compensate for this sure would be nice).

All the same, if you're considering sliders, you might be interested in this page I came across a couple weeks ago:

http://www.diymetalfabrication.com/how-to-build-leaf-spring-sliders/

If you already have a good supply of steel stock to pick from, then the only thing you might need to pick up would be the UHMW, which can be had for much cheaper than what the author mentioned they paid.



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