Determining shackle hanger placement?

Caver Dave

Caver Dave

Just holdin' it down here in BFV
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Mar 10, 2005
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Several years ago I installed a set of Toy mini-truck leafs (3" Downey... thanks again SeaFlea) in front of the Moss. Flipped end-to-end, the pin offset was close enough to "bolt-in" and flex like mad. After 35+ years to OEM leafs were toast, multiple re-arching, AALs, etc made them ride/flex like a dumptruck.

Fast forward 2 years... I'm very happy with these leafs, except:

A) they have SO MUCH droop, I'm encountering the shackles inverting when the frontend is both unloaded (uphill) & against an obstacle

B) they're about 1.5"-2" too tall for my liking

My original plan involved removing the Commando/Waggy style shackle/hanger arrangement (IMHO too much distance from the frame) and trying the "sliders" (like JC did), but now think it may not work well without a SRS. Now I'm thinking it'd be both faster & better to replace the existing setup with a thru-the-frame style shackle hanger/bushing and CJ style shackles. This should both drop the frontend down AND reduce the inversion occurrences. My main issue now is determining the best placement for the shackle bushing in the frame. Pretty sure the weight needs to be on the leafs, but I'm unsure the best way to accomplish it AND have a good shackle angle when done, so I'd like to get it very close on the first shot!


So, what are the tricks for insuring proper shackle geometry for repositioning the fixed end of the shackles?
What about determining optimum shackle length?

Current arrangement, but shackles have been replaced with NEW Chevy "747" shackles (to eliminate the crackhead welded shackles that nearly cause catastrophic failure in VA)...
attachment.php


:popcorn: :beer:
 
Caver Dave said:

So, what are the tricks for insuring proper shackle geometry for repositioning the fixed end of the shackles?
What about determining optimum shackle length?
beer:
Click to expand...

Multiple holes in the mount and/or drill as needed or be able to move one or the other without major wheelbase change or wheel centerline. Unless you have some EXACT history on hanger placement, for those leaves, that truck and this shackle then minor trial and error isnt that bad
 
You should be able to measure the length of the spring eye to eye, with the weight on the truck. You could then use a piece of string out at that length to see where the end would be if you moved it up. For shackle length, I would guess about 5" as a minimum length. 6-7" is probably ideal. If you go too long with front shackles, the steering wheel will just push the axle back and forth under the frame, when in rocks, while the shackles move side to side. Boxing the shackles, not just two flat plates, should help immensely with that along with stiff bushings.
 
heres how i do it:
1. put everything together except for the shackle and shackle hanger (or bushing through frame) with the frame jacked up
2. put a piece of 3 or 4" channel across the frame open side down with the shackle end of the springs sitting inside of it.
3. stack wood or metal blocks between the frame and channel to get the clearance for whatever size shackles you want to run (i dont know how to figure optimum shackle length, i just guess at what looks right)
4. now drop the truck down so all the weight is on the springs, now you can mark where you want your shackle hanger or bushing hole to go so that you have the angle you want.
 
Franklin said:
Multiple holes in the mount and/or drill as needed or be able to move one or the other without major wheelbase change or wheel centerline.
Click to expand...

I had thought of that, but the non-boxed front rails aren't very conducive for an "adjustable" mount"... but will definitely consider

Franklin said:
Unless you have some EXACT history on hanger placement, for those leaves, that truck and this shackle then minor trial and error isnt that bad
Click to expand...

That's an idea that hadn't occurred to me bro... mimic the dimensions from an actual truck!
Anyone care to measure up the rear of a '80s Toy minitruck/4rnr for me?
- Rear spring (fixed) hanger hole center to bottom of frame? (for S&Gs)
- Above hanger hole to shackle hanger center?
- Center-to-center length of stock Toy rear shackle?
- Any other measurement you think may be critical?

:beer:
 
I can measuse all this stuff for your tomorrow morning when I go to the shop. Whats your phone number and I will call you and give you the measurments
 
Dave, I PMed you the measurements from my old OE leaves etc.
One note - what year toy leaves do you have? It occured to me just now that if they are Pre-84, they will be diferent than the 85-89 leafs.
 
Caver Dave said:
Got them from SeaFlea... I believe his 4RnR is later '80s style?
Click to expand...

well, you have a 2/3 chance of that, 84-85 I believe would be the old springs, 86-89 newer ones, that's what mine were.
84 and 85 are a little unclear to me, as that was the 2nd gen body style, but before the IFS change when the leaves got wider and the axle changed, so I'm not sure if they match 80-83 or not.
 
Anybody else with a Toy to measure?

I got this from RLG and appears I'm at 45" fix hanger hole to shackle hanger hole and the shackles are 4.5"...

RatLabGuy said:
Guestimate of length from fixed mount to shackle frame mount is 45.5", +/- .5" (guessing where old location was based on nicks in frame)

Stock shackles 3 3/8" eye eye
Click to expand...
 
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