The Stovebolt Site Forums The Shop Area Driveline Front Shackle Seal Repair

Hi Everyone,

I need to replace the seals on the front shackles of my 1953 3100. I've read in other posts about jacking up the truck and then using a floor jack to relieve tension on the leaf springs. What I didn't see and can't figure out is exactly where to put the floor jack. I've got the truck on jack stands under the frame near the firewall and the shocks are removed. Where should I put the floor jack to relieve the leaf spring tension so I can disassemble the shackle? Should it be in the middle of the leaf spring arc or directly under the shackle? Thanks in advance!

Either place would work, but under the axle would probably give the jack the most secure purchase. You want the axle hanging free on the springs, then jack the axle up just enough to make the springs relax completely. You probably won't be able to do that when you remove the shackles, but putting them back together, you'll need to adjust the height of the spring eye to line up the shackle links.

Kevin,

Awesome! Thank you!

UPDATE:

Using the floor jack, I was able to relieve the pressure on the leaf spring and with several blows from the hammer, the passenger side shackle came apart. What I found when I went to install the new grease seal was that the bottom shackle pin could be wobbled in the bushing. Upon closer inspection, both the bushing and pin were damaged. The bushing was actually missing a piece and the pin was severely worn. I've attached a pic of the pin. So, I'm in for a complete rebuild, not just new seals. Not too surprising, I guess.

For those who are going to do the same repair, I found that it took very little upward pressure from the floor jack to allow for disassembly of the shackle. Your mileage may vary.

Final Update:

With everyone's help, I was able to make the repair! I used Pre '68 Dave's spring shackle removal tool to both remove the old bushings and install the new ones. I used NOS parts. Included is a pic of the finished effort on passenger side. I'll do driver's side next.

Once again, Thank You!

Did you do the bushings at other end of the spring,I found mine to be worn also.

I thought about it, but had no play in the rear spring mount that I could find.... Hopefully that doesn't come back to bite me! I still need to do the driver side, maybe I'll take the rear off, too, and see how it looks. If it is bad, then I'll circle back and do the passenger side.

I did not think mine were bad until I took them apart. The one thing after I noticed is to look at were the spring cups into the spring mount on the frame (if the spring is close to the mount it is worn)They were not to hard to take out and if you do check them the parts I got were a good price from rock auto.

You need to check them. If they go too long, the bolts will get into the spring eyes and ruin the spring.

You are right. I was really hoping to get by as quickly as possible, but doing it right is what makes sense. Later this weekend I'll get some time in the garage. I'll start with the driver side and then circle back to the passenger side. We'll see how they look!

I pulled the driver side and found that the bolt was worn (pic below). The question that I now have is how do I get that odd sized (11/16-16) bushing out? It seems as though no one makes all thread of that size. So using the same home made tool that I used on the front shackles (5/8-11 all thread) won't fit. The follow on question is how do I seat the new bushing without damaging it?

EDIT: I answered my own question by taking a closer look.... The threaded end is only on the bracket that is attached to the frame rail. The bushing only goes through the leaf spring, so I was able to use the home made tool to get it out. Sadly, it was missing about a third of the bushing, along the bottom. There was a small amount of wear in the spring itself, but I won't know for sure if it is salvageable until the replacement bushing and bolt come in later this week. I've added a second pic of the entire assembly after removing it from the truck. If the new bushing fits snugly, I'm thinking that the leaf spring is salvageable. I'm really hoping that is the case, as a new set of front springs is unplanned and will set me back quite a while if I have to save up for them.... I'll update when I know.

Something I’ve been wondering about....

What was the idea with the threaded shackle pins on these early trucks? Thinking specifically about the rear suspension, rear shackles on an AD truc.


If I picture in my mind how this works: spring compresses, shackle pin has to rotate, rotation along the threaded pin causes it to move to one side or the other. And that happens non stop, all the time, as the vehicle is driven.

Would seem that the “seal” would be constantly compressing on one side and opening up on the other.

That's the way they would work. The seals on the replacement shackles I bought are rubber washers, where the originals were felt, so the newer ones should compress and relax better.

The shackles only rotate a few degrees, so the lateral movement is pretty limited. The shackle threads are 5/8 x 11 TPI and would only move 0.09 inches per full revolution. So for say a 10 degree rotation of the shackle, that would only be only about 2-1/2 thousandths movement.

Ok, I was picturing more rotation than that. Good explanation.

The contact surface on a threaded bushing is much more that of a flat bushing. In theory should minimize wear.

Mine looked just like yours and the spring eye had a little wear also .the bushings I just used a punch to get them out and used a big c clamp to put the new ones in.l guess to remove them you could use the c clamp with a socket that is slightly smaller and push it out. Mine came out with no problem they were greased up pretty good .

FINAL UPDATE:

I got the parts in from Rock Auto and swapped out both shackle pins and bushings. Both pins were worn, as were the bushings. There was some erosion in the leaf spring, but not enough to allow me to just push the bushing into place. Instead, I had to press them into place using the home made tool.

As to the Rock Auto parts, one bolt was fine. The other had threads that weren't quite right. Even the nut that came with the new bolt wouldn't thread onto it properly. I ended up using the old nut to chase the threads on the new bolt. This then allowed the new bolt to work as designed.

Thanks again to everyone for the help and advice!