CJ7 Leaf Spring Mounting Dimensions Needed - JeepForum.com
 
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post #1 of 15 Old 11-13-2019, 03:00 PM Thread Starter
mpcwillys
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CJ7 Leaf Spring Mounting Dimensions Needed

Hello,

Iím planning on using CJ7 leaf springs on my Willys Truck and I need some help with the stock CJ7 leaf spring locations.

For the both the front and the rear, what is the dimension from the eye of the shackle hanger to the eye of the leaf spring mount?

Iíll be switching over to the CJ7 spring mounts and shackle hangers with the Willys truck frame already completely separated from its cab and bed, so I canít put the leaf springs under full weight of the truck to locate the mounting positions. Thanks.

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post #2 of 15 Old 11-13-2019, 04:19 PM
Fourtrail
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Dimensions G 40.61 and H 46.16. these measurement are to the far hole from the bushing mount on the shackle hanger, the bushing end of both the front and rear hangers go toward the front of the Jeep.



80 CJ-5, 74 CJ-6, 56 CJ-5
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post #3 of 15 Old 11-14-2019, 08:55 AM
BrutusBlue
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In the front, from the eye of the shackle hanger to the main eye of the leaf spring hanger is 43, in the rear it’s 44. I would not use a CJ7 spring in front. The CJ7 spring is not near as good a ride as a YJ spring. I have been toying with new springs for my Willys truck for years and CJ7 springs are not on the list. The front YJ measurement is about 44 like the rear.
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post #4 of 15 Old 11-14-2019, 09:32 AM Thread Starter
mpcwillys
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Thanks for the replies. I'm not sure I understand exactly where the G & H distances are measured from. Those are different locations than from the eye of the shackle hanger to the eye of the leaf spring hanger?

I'm not locked in to using CJ7 leaf springs. I just know I want something wider than stock and I have the CJ7 stuff available already. I'm not that familiar with the YJ springs, so I'll look into those. Thanks for the input.
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post #5 of 15 Old 11-14-2019, 09:55 AM
Fourtrail
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Quote:
Originally Posted by mpcwillys View Post
Thanks for the replies. I'm not sure I understand exactly where the G & H distances are measured from. Those are different locations than from the eye of the shackle hanger to the eye of the leaf spring hanger?

I'm not locked in to using CJ7 leaf springs. I just know I want something wider than stock and I have the CJ7 stuff available already. I'm not that familiar with the YJ springs, so I'll look into those. Thanks for the input.

G & H are the measurement from the center of the spring hanger to the bolt hole for the shackle hanger. There is no fixed point on the frame itself for the shackle hanger center. As I said in the first post, the bushing/shackle hanger goes toward the front of the Jeep on both the front and rear shackle hangers.



80 CJ-5, 74 CJ-6, 56 CJ-5
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post #6 of 15 Old 11-14-2019, 11:24 AM Thread Starter
mpcwillys
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OK, I think I've got it. From the center of the spring hanger bracket (not the eye of the bracket) and to the center of the shackle hanger bracket (not the eye of the hanger). That is why the distances G & H are different than the eye to eye distances provided by Brutus Blue, right?
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post #7 of 15 Old 11-14-2019, 11:44 AM
Fourtrail
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Correct

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post #8 of 15 Old 11-18-2019, 05:40 PM Thread Starter
mpcwillys
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Quote:
Originally Posted by BrutusBlue View Post
I have been toying with new springs for my Willys truck for years and CJ7 springs are not on the list. The front YJ measurement is about 44 like the rear.
It looks like with either of these options the front of the frame will need to be extended a bit. The distance between the stock mount locations is about 35.5". So to keep an axle at its original location a 44" long spring will move each mount (leaf mount and shackle hanger) about 4.25" away from the stock location. On my frame, I don't have that much room until I'm into where the stock front bumper sits.

BrutusBlue: were you planning on adding on to the front of your frame/frame rails to be able to fit a spring of that length? I'd prefer not not mess with where the stock bumper is in relationship to the grill, but it looks like it will have to move forward a couple of inches if I want the longer springs.
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post #9 of 15 Old 11-18-2019, 08:28 PM
BrutusBlue
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Yes, I had originally planned on extending the frame out in order to accommodate longer springs. Then, as an experiment, I built/widened a CJ7 frame to fit under the truck cab by cutting it apart, widening it to fit a wagoner front axle by removing the front cross member, welding up a pipe front cross member and adding a 2x4 boxed frame in the rear. The CJ frame was cut where the rear area rises up over the axle and instead extended straight back with the welded up 2x4 box frame to accommodate the truck bed area. I intended to use Chevy rear leaf springs and Wagoneer front leafs.

After all the effort, I have now decided to change direction. I bought a TJ frame to hack up instead (literally since my last post). I will now be building a front axle on a front 3 link and a rear 4 link. Google “Wicked Willy’s part 1” A front 3 link and rear leaf spring on an original frame would also be a great deign.

I had the same extended front frame horn concerns. I saw an extended TJ/LJ type set up on a Willy’s truck in Ouray, Colorado (our yearly trip) while on vacation this past summer and it seems to be the cleanest design so far, while keeping the original short front frame profile. After finding the same truck on another forum, I decided to go ahead and take the TJ/LJ frame plunge. For me, it is about as much work to modify the original frame for leaf as it is to hack up and fab a TJ frame for a link set up.

If you prefer a leaf spring then I would extend the front frame horns, weld in new perch’s front/rear and be done. Just accept the extra space within the front frame area, no way around it unless you do a 3 link setup. I do love the simplicity of a leaf spring setup. The link design will be my first.
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post #10 of 15 Old 11-19-2019, 09:35 AM Thread Starter
mpcwillys
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Wow, you have some time into this. We sure work hard at our hobby.

I'll end up extending the frame. This truck has to end up highway drivable or it's useless to me. Relocating leaf spring mounts are doable for me and my quickest route to getting this thing assembled, but your truck sounds like it will turn out great. Thanks for the info.

Last edited by mpcwillys; 11-19-2019 at 10:01 AM.
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post #11 of 15 Old 11-20-2019, 11:29 AM
BrutusBlue
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When you mock everything up, make sure your leaf spring main eye holes are lower to the ground in relation to your bottom shackle eye holes on both the front and rear. Make sense?
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post #12 of 15 Old 11-20-2019, 01:57 PM Thread Starter
mpcwillys
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What is the reason for that? With the front axle, that should be easy enough if the shackle stays in the front (but I may do a shackle reversal).

For the rear the frame is mostly flat, so it looks like if I had say a 4" shackle, the bottom eye of the shackle (where the leaf spring connects) would be closer to the ground than the leaf spring main eye hole for the hanger that is attached to the frame.
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post #13 of 15 Old 11-20-2019, 02:33 PM
Fourtrail
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Quote:
Originally Posted by mpcwillys View Post
What is the reason for that? With the front axle, that should be easy enough if the shackle stays in the front (but I may do a shackle reversal).

For the rear the frame is mostly flat, so it looks like if I had say a 4" shackle, the bottom eye of the shackle (where the leaf spring connects) would be closer to the ground than the leaf spring main eye hole for the hanger that is attached to the frame.

That is so you have positive caster for the front axle without needing to use degree shims between the spring and the axle spring perch. The rear is not as important as you can weld the spring perch on for correct pinion angle.

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post #14 of 15 Old 11-20-2019, 11:18 PM
BrutusBlue
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On the front shackle, you donít want the front spring eye lower than the rear main eye for stability reasons. Caster can be built into the axle after final positioning of the leaf spring, by shims or turning the outer Cís.

The length of your shackle ultimately plays no part in stability or caster if you account for caster after you set yours springs. If you install extended shackles after having set your axle then caster has to be addressed which means resetting your axle all over again. From the direction your going, you would want to decide on the proper shackle length first then set your axle after having full weight on your springs.

A quality, heavy duty shackle can be extended and be perfectly stable so long as caster is accounted for and the bottom leaf eye at the shackle is still higher than the main eye, whether itís reversed or not.
On the rear, the stability problem is not as pronounced but can still be a problem.

Iím glad you mentioned a shackle reversal. A shackle reversal will make the issue even worse, if the main high is higher in front than back.

A wonderful build thread on a couple of forums of a particular Willyís Wagon where the previous owner did a superb job of reconstructing and repowering with a modern drive train, had a shackle reversal that was very poorly designed with the shackle well below the main eye. Videos of the performance at low speed proved obviously bad. Almost a first rate resto-mod if not for the poor front suspension setup. The Wagon had another problem often overlooked. One thing you never do is mount a lifted, arched spring in a shackle reversed configuration with the main eye in front that is higher than the rear bottom shackle eye. Big time stability problems in two areas.

The problem with many shackle reversed set ups is two fold. Improper relation between the height of the two ends and arched springs. A shackle reversal is only meant for flat springs where the spring grows shorter under compression and the reversed shackle moves forward not backwards. Arched springs never reach the point where they grow shorter in length under compression before they bottom out. Shackle reversals have a place but only on flat springs. Stay away from a shackle reversal setup where you intend to go SUA on an arched spring. If you plan on running a very flat spring on SOA then a shackle reversal works great.

Decide the overall setup you want and attack the front first, You can make the rear work much easier after having finalized your front setup. A front shackle reversed flat spring would work great and appear cleaner than extending your front frame horns WITH a big honker shackle sticking out from under. Several aftermarket reversal kits include a very low and pronounced front main eye mount to address the lower mounting point vs the rear reversed shackle. Look at the IH shackle reversed kits for Scouts and Travel-Allís, kinda a goofy with two big front main eye mounts hanging way down but necessary to get the eye lower.

On the rear, I would box the frame in a small area where you can weld some tubing through the frame and insert a bushing where the top shackle bolt would mount, like on the rear of a YJ for instance.

Nothing at all wrong with running a front SOA reversed shackle in front and a rear SUA or the other way around.

Keep us posted, would love to hear what route you go.
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post #15 of 15 Old 11-21-2019, 10:29 AM Thread Starter
mpcwillys
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Wow, great info! Thanks guys for taking the time to pass along that info. Very helpful.

I'll see if I can come up with a plan over the holidays. It's a long term project and you've given me a lot to think about.
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