Spring spacing with MP offset hangers/shackles.

Author Topic: Spring spacing with MP offset hangers/shackles.  (Read 1174 times)

Offline Jim

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Spring spacing with MP offset hangers/shackles.
« on: November 05, 2008 - 12:53:25 PM »
The rear axle has been narrowed and the springs moved in on my 72 Cuda. The previous owner did this. The rear suspension is not yet assembled.

I’m starting to put things together, but I really don’t like the way the springs are hung at the back. Without getting into detail, it will probably work, but it’s less than ideal, so I’m re-engineering it.

The springs have been moved in about 3”, but I only need about an inch. I think I can get the tire clearance I need simply with offset hangers and shackles, but I’ll need to move the spring perches on the axle back outboard somewhat. The axle has been narrowed, and moving the perches back out will put them very close to the welds on the tube ends, possibly not leaving adequate space for the U-bolts. Exactly how close, is what I’m trying to figure.

My question is for anybody running the MP offset hangers and spacers on an E-body. What is the spring-to-spring distance, or more specifically, axle perch to perch distance?
-Jim
"Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it. "




Offline ntstlgl1970

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Re: Spring spacing with MP offset hangers/shackles.
« Reply #1 on: November 05, 2008 - 02:18:03 PM »
Don't quote me on this but I think mine measured out at 45 5/16" (I wrote it on the rear end). I would wait until you get the springs and hangers, mount them and then measure what it is before welding the perches on. For the reason that every car is different and you will need to set the pinion angle correctly before welding.
70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

Offline Jim

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Re: Spring spacing with MP offset hangers/shackles.
« Reply #2 on: November 05, 2008 - 06:37:13 PM »
Don't quote me on this but I think mine measured out at 45 5/16" (I wrote it on the rear end). I would wait until you get the springs and hangers, mount them and then measure what it is before welding the perches on. For the reason that every car is different and you will need to set the pinion angle correctly before welding.

I don't plan to purchase anything until I can determine if I've got enough room to move the perches.

Offset hangers move the springs .80" per side. I think I can figure it out from here. Just need to take a few more measurements.
-Jim
"Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it. "

Offline ntstlgl1970

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Re: Spring spacing with MP offset hangers/shackles.
« Reply #3 on: November 05, 2008 - 08:19:23 PM »
just fyi - the offset hangers do two things, move the tires in and straighten the springs out a little. Stock the springs angle towards the center of the car. So the offset of the front hanger and rear shackle may not be the same.
70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

Offline Jim

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Re: Spring spacing with MP offset hangers/shackles.
« Reply #4 on: November 05, 2008 - 10:37:03 PM »
I've got a pretty screwed up situation right now.

My axle is 41.75" center to center on the springs. I could possibly move the perches out 1" each side, putting me at 43.75".

As you state, offset shackles and hangers put you at about 45.25"

My axle is 2" too narrow to work with the 0.8" offset shackles and hangers.

That means I either need to scrap the axle, or somehow install a new rear hanger inboard of the longitudinal.

I'm not quite sure how to construct a new hanger and make is strong enough. I've been searching for pictures of some examples but have come up empty thus far.

-Jim
"Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it. "

Offline ntstlgl1970

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Re: Spring spacing with MP offset hangers/shackles.
« Reply #5 on: November 06, 2008 - 12:07:37 AM »
I would try posting your question on moparts, I think more people have done the offset hanger installation there. Hopefully someone will provide a straight answer. Like I said, take my measurement with a grain of salt, I made it over 15 years ago - that number could be totally wrong.
70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....