Rear shackle ID and replacement options? (1 Viewer)

swelltimes

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I'd like to replace my rear springs and shocks, and am considering replacing the shackles and bushings as well. My truck is a 6/77 FJ-40, almost completely stock (as far I as can tell).

Seems like the current rear shackles are longer and a bit more stout than the stock shackles on the front springs. Pics attached of the rear.

I've read that some folks do this to compensate for a sag in the rear end, which my truck currently has.

I've got some gently used stock springs I picked up from a local cruiser enthusiast, which I'm hoping will help correct the sag.

Anybody have a similar set-up on their stock rear suspension, or any recommendations as to a good next move for me? Re-use these with the newer springs and new shocks, or go back to stock? Seems like going back to stock would worsen the sag.

Thanks!

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More pics would help. Side view, front springs, hard or soft top(weight), tire size, etc. There are a lot of factors to consider. Stock shackle size is 2 3/4" from pin to pin.
 

swelltimes

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Fast Eddy, thanks for the advice. Will do.

Side view of truck attached, tire size is 235 / 75 R15.

So, current plan is to replace rear springs, bushings (front and rear), use new u-bolts on the rear, and replace rear shocks for now. I've read a lot of good feedback on the Bilstein 5100. Aside from paved roads and running errands, most of my driving is old class 4 -5 roads and trails.

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It sounds like you have a good plan. Bilsteins are about the best you can get for a cruiser. For the shackles, for every inch you will get an extra 1/2" lift. Good luck with the springs.
 

swelltimes

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OK, ordered up some Bilstein 5100s, two new stock-length shackles for the fronts, bushings, and u-bolts. Will update as the parts come in and I carve out some time to do the swap. Thanks for the advice, folks.
 
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Looks like the old con fer shackles. Reuse them. I'd probably also cut the bar in the middle in half, which will improve flex and ride quality at the cost of bushing life (never was an issue for me FWIW).
 

swelltimes

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I finally carved out some time to get in the shop and tackle this project, and am running into some issues.

Overall, my goals are to replace the clapped out Rancho shocks, replace the old / missing bushings, and fix the rear-end sag that I have in the truck.

My plan was to replace the rear springs with some newer (but used) stock springs, hoping that would correct the sag.

Upon removal of the pass. side rear spring, and comparison with the springs I was planning to swap in, I don't think that'll make a difference. They all look to have the same arch while they're on the floor of the shop, so I don't think the replacements will hold the truck up the ~3 - 4" I think I need.

Another issue is that the greasable bolts I bought for the rear shackles are too big, by a mm or two, to fit into the shackles. So, I can drill the holes out just a touch more, and that should be fine.

So, my big question here is how do I level the rear end out to remove that sag? Do I search for some mild lift springs to put into the rear? Or do I replace the shackles with something longer? The second option doesn't seem to be the best way to go, since I think I have more sag to correct than is reasonable to compensate for with a longer shackle.

Other relevant questions / points:

• I don't drive my truck when there's salt on the roads. Should I take the time to clean up and put paint / POR on the plate the u-bolts go through? They currently have some surface rust, but not much, since the truck was from CA.
• When I need to shorten the new u-bolts, what's the best way to do that? Run the nut on to the bolt past where I need to cut, make the cut with a hacksaw, then run the nut back off? Another way?
• I have poly bushings, so is a lithium-based grease like LMX Red Grease a good way to go?

Eager to hear what you all think, and how I should best proceed here to get our truck back on the road. The pictures I posted before should be helpful.

Thanks, all!
 

swelltimes

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@tls3601 cool, I'll have to look thru Murf's threads.

Going to swing by my local Fleet Pride this week, and see if they do re-arching. I wonder if I'll have to give them a certain measurement or other specific info for the re-arching: anyone know?
 
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I had the rears done on my '76 and they're still ok after some years (8 years?). If cost is no object, I'd have Alcan make a new set. They'll want the weight on each of the rear wheels. Cost was $220 each last I heard.
 

swelltimes

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@Fast Eddy, thanks for the info. I think I'll try to go the rearching route for now, since I'm planning a full rework of the truck in a couple or years, and should be able to put some new springs in then.

Any recommendations for figuring out weight on the rear wheels??
 

swelltimes

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Since I have the hard top and sides off right now, and am prepping the top for a repaint, I think I'll have to hold off on weighing the truck. I hope to have the top back on before too long, and will get it weighed and take it to a spring place then.

In the meantime, I think I'll just replace the shocks and suspension parts that I have here, and deal with the springs as soon as I can.

Thanks for the help, all.
 

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