The Stovebolt Site Forums The Shop Area Driveline Lost a Shackle

I took more than a year and a half to get my front disc brake project and my overdrive transmission project to be finished and working as they should. I had three days with lots of time playing with and enjoying my new toys. Yesterday while driving it felt like I ran over something big, but there was nothing there. Next there was a bigger bump, still with nothing there. I stopped and looked around the differential but found nothing wrong. When I got back home I determined to put it back on blocks and leave it there until I find out what is wrong. It did not take long to find that I lost a shackle. I bought new rear springs during 12-2023 then installed them during 3-2024, so they are not old and do not have a lot of use on them. I retraced my route 3 times but did not find the pieces, so I do not know why I lost it.

Tomorrow I will order another shackle kit from the supplier and try again.

If you had it bolted the way the picture shows, the nut is on the wrong side of the plate. Now if you had a second nut on the out side of the plate, then the inner nut should not be there. The plates have tapered holes to fit the pins tightly, and the nut & bolt are a secondary backup. The nut should just be tight enough to very slightly bow the shackle plates with a single lock washer to retain it. You could also use a lock nut or top lock nut, just not a nylon type lock nut. I use a socket over the protruding pin to seat the plate to the pin, then tighten the bolt. When removing them, it should be necessary to tap the plate to break the tapers hold. Where are the grease zert holes?

+1 on what Joe said.

Alternatively, you can get a shackle kit with nuts on the pins instead of it being help together with the carriage bolt.

Thank you! I left out the words, but my reason for posting was to ask about installer error. The nut shown is a 2nd nut to the outside one. I will change that. I put all 4 corners that way. The grease fittings are on the outside.

I would get someone to help you. Not understanding why you put a nut on the inside of the shackle's.
Did you do the front disc and OD trany ?

Perhaps I am interpreting the pictures incorrectly but it looks to me like your spring mount (welded to the frame) broke away and is missing. You need more than a shackle kit. Your first picture shows poor penetration of weld holding the opposite side spring mount. From the factory those mounts would have been riveted.

Kent

when I first looked at that, thats what I thought. that spring bucket/mount broke, but I think its still there.
although the pics are of the left and right springs. IDK

I would say it was installed loose, the double nut didn't let you pull the plates tight into the tapers or wasn't pulled tight before the second nut was tightened down. Correct the others, buy a new one, and move on. Lesson learned. Seat the tapers next time.

Gents - If you zoom in on Robert's pic with the missing shackle pieces (I snapped a pic and attached below), that spring mount is still on the frame and there isn't any evidence of welding on either side of the truck rear end. Rivets all seem to be in place and frame mounts secure.

Robert, I would venture to say either the cross plate bolt broke or the outer nut did loosen and come off leading to loss of the shackle side plates. I would 2nd Joe H's guidance on the shackle installation process. Change the other three to the proper installation method and replace the missing one the same way. The addition of the inside nut probably led to the outer nut not having sufficient tension to stay in place, so leaving that out is a must.

Glad to hear there wasn't catastrophic damage or injury involved in the loss!

Thank you all for your additional information. I claim that I seated the shackles before installing the bolt, but, if not seating them caused this problem, then I must not have done it. The original shackles had been tightened enough to bow them toward each other. I did not like that plan. My plan with the 2nd nut was to have something for the outer nut to positively tighten onto rather than chance bending the shackles. I can rethink that, if that is wrong.

I forgot about that ugly weld. This truck was hit in 1980 something. The man's insurance company sent my truck to a shop, and I got what I got. I do not know why the shop added those globs. The rivet is still in place. I have an excellent welder who helps me out now, but he was not born until 1990 something.

I added more photos. One better shows that the spring mount is in place. The other one shows my double nut scheme.

I ordered a replacement shackle kit today.

Again, thanks!

Robert, If all you need are the plates I can send you a pair. I probably have the bolt as well. Send me a pm if you have not already ordered.

Robert, I'm looking at the upper spring hanger pin in your second picture...is it broken or just pushed through to the other side, it looks short.

Your bolts look long enough to put a jamb nut on top of the main nut if you are concerned with them backing off.

Mike B

Thank you for your observation. It does look shorter. I do not suspect broken, but I will report when I next have a look.

Well, I guess I did, indeed, misinterpret the original pictures. I am glad the spring hanger is still there. A properly installed shackle should fix things up. Perhaps the right side was welded after the accident stretched the riviets, but we will never know.

Kent

A home built motorcycle trailer I bought a few years ago had a very rough ride- - - -almost shook the tiedown straps loose on my Harley the first trip I made with it. Then I discovered that the builder had bolted BOTH ends of the springs solid to the frame! A set of shackles and some small shock absorbers made a huge difference in the ride.
Jerry

I'am lucky to have a Fastenal close by for hardware, these will not back off ( https://www.fastenal.com/product/details/11541119 ).

I have the shackle repair in place. Poster Twin Jimmys provided a set of original shackles. They are 3/8" thick and fit perfectly onto the pins. The replacements are 1/4" thick. My earlier photo shows the shackle pins to not be centered within the spring or the mounting bracket. I do not know if they moved after assembly or if I installed them that way. That does not seem like something that I would do, but I do not know. Centering the pins leaves them protruding 5/8" out each side. I adjusted both pins on each side to that. I used a c-clamp to ensure that the plates are tight onto the pins.

One shackle in the new kit fits well. The other shackle looks like the holes were chewed, rather than cut, and it does not fit fully onto the pins. Because of receiving original shackles, I did not have to use that. Thank you to Joe H for the locknut part number. I may get those later. The provided locknut has 5 (maybe 6) dots marked. The closest that I can match to a chart is Grade 8. I did not use my 2nd nut in this redo.

Later today I will have a test ride.

Thank you to everyone who offered advice.

The repair is holding. I found when I reset the pins that the lower pivot bolt was finger loose to turn in the direction to make it more wrong, but I needed vise grips to get it to turn back to where it should have been. I took that pin out and cleaned it and the mating internal threads. I was gifted with a 2nd set of original 3/8" thick shackles, so all 4 are now original parts. When the pins are centered to protrude the same distance on both ends they measure 1/32" out of the shackle. I now check those shackles after almost every trip of more than a few miles. The pin that was stuck in one direction has moved to be flush with the shackle, but otherwise all seems to be well.

That looks like the shackle is all ready to slip off. Why not get this shackle kit he suggested?

I dealt with some TERRIBLE aftermarket shackles.

Pins lacked the proper taper and wouldn’t seat in the side pieces. I finally modified and made them work, but bought some NOS that I am going to install when I get a chance.

Thank you for your additional advice. I am confident that my problem was caused by that one pin rotating only one way as the spring worked back and forth. I had the bolts double nutted, so I do not believe that the nut backed off. I also do not believe that the bolt broke. The pins of the right side shackle assembly have not moved. I check it frequently, and the left side is holding at its having moved 1/32 inch since I fixed it. For now I'll keep checking and go with what I have if it holds where it is.

Again, thanks!