The Stovebolt Site Forums The Shop Area Driveline 1954 3600 shackle bushing source

Good morning, The bushings that press into the rear spring shackle on my truck are shot. I've looked at the usual websites and don't see any listings for these. Anyone have a source for these?

I measured the bore of the shackle and got .996 and the diameter of the pin and got .874 and about 1.125 long. Not prfect measurements since I'm not a machinist but should be close. I checked MSC industrial supply and found THESE. Not as long as the originals But I think they should be close. Any thoughts??

Thanks!!

Classic parts offers this. More than just the bushings at more $$.

The Filling Station lists them for 1937 - 1955 1/2 ton models, $12.95 each.

https://store.fillingstation.com/detail/RW-22/Chevrolet_19371955_TRUCK_REAR_SPRING_BUSHING.html

Thanks Bill but the truck came with a whole bunch of new parts and I only need the bushings, not the pins. I think the ones I found at MSC will work even though there .125 too short. This truck will likely never see a big load anyway.

TUTS, thanks but those are the spring eye bushings, not for the shackle. Does anyone know if the ones at the filling station and other vendors are solid bronze or have a split like the originals? I think MSC has a bronze bushing of the correct size as well. Thanks!

Correct me if I'm wrong but aren't they the same?

Sorry John but on the 3600 truck they are not. I'm real new to all of this but when I knocked them out they were two completely different bushings.

The bushing usually comes with the shackle on chevy trucks. But one chevy book (1950) and all my GMC books listed the bushing part number as 594664 0.875 I.D., 0.998 O.D., 1 1/8 LGH. Two per shackle.

Spring Shackle Bushing

Oswald - Perhaps it would help everyone better understand what bushings you are taking about by posting some pictures of the bushings and where they came from on your truck? You described measuring the bore of the "shackle", but in my minds eye the bushings are in the spring "eye" that the shackle attaches to. All the references I have found so far indicate the bushings are they same size, part number, etc.

Pictures will help clear up any misunderstandings about what the actual parts are that you are describing please and thanks.

Dan, you may be thinking of the typical shackle that has bushings in the spring eye and the frame mount with pins and bars on each side.

But 3/4 ton trucks apparently have a different type of shackle, a male and female setup if you will.

Here is a link that has a picture.

Maybe the PO can give the Filling Station a call and see if they have the proper bushing (the one that goes in the frame or the one in the spring eye)

Thanks for shining the light for me Kevin! Makes very much more sense now that the critical picture is provided. Which is kinda where I was going above as my minds eye wasn't grasping the correct picture.

Did you happen to try and look up the original bushing for the shackle in any of the Chevy Master Parts books? The only one that I ended up finding was the spring eye bushing, which is clearly only one of the two he needs.

Dan, I did look in the online 1929-1954 parts book earlier, but wasn't able to nail down a part number.

Thanks Kevin! I did a little further research now that I better know what the part in question is and can provide the following info on the this rear spring shackle in question.

The original GM# 3705599 is described as a shackle, rear spring w/bushing (no separate part number given for the bushing) as listed in the 1929-54 Chevy Master Parts Book and earlier editions. The 1929-57 Chevy Master Parts book lists the same part as GM# 3725531, described as a shackle, rear spring w/ 7/8" bushing (still no separate part number for the bushing). An even later Chevrolet Part Number Replacement and Supersessions book indicates that GM# 3725531 was replaced with GM# 3896376 in 1979. Still not indication of a separate number for the bushing.

If Oswald isn't able to make the bushing he found work, there are still a few NOS rear spring shackles with the bushings under these various part numbers offered for sale in current ebay ads. Just search the listed part number and you will see what's available.

OK, I laid the pieces out and took a pic to clear things up (See link below). As far as measurements I took them using a reasonably good vernier caliper. Here are the measurements:

Pin diameter: .872" just under 7/8"

Closed end of the shackle hole (top): .992" just under 1"

So I'm thinking of 2 bushings 1" OD and 7/8" ID and 1 1/8" long (if I can find it) or the 1" long bushing I found. Here's the link that shows specs of that bushing:

https://www.mscdirect.com/product/details/00458760

Spring eye ID: 1.120", just under 1 1/8"

That would make the spring eye bushing 1 1/8" OD, 7/8" ID and 2" long. That's easily available as has been pointed out. Hope this helps clear things up


Spring shackle components

Shackle 3705599 was used on the1954 GMC PM150 (3/4 ton), PM250 (1 ton) and the 250 panel body truck, the same shackle that is on your truck.
The replacement shackle bushing is 594664 for the 3705599 shackles.

So the bushings you're looking for are in the upper part of the shackle, correct? I'm assuming the upper pin is tight to the steel of the frame mount and doesn't rotate in it. Does it have a lock bolt like the lower pin does?
With the dimensions you gave, you could buy one of the spring eye bushings and have it machined to the correct OD to fit in the upper part of the shackle. I'm sure you have a friend with a lathe, right?

Oswald - Using jimgmc's "GMC" bushing part number, these appear to be NOS Bushings that will give you the exact part needed. The listing says $15 USD for a pair of bushings (1 shackle) with 8 sets of bushings available. Best of luck sir with your search sir!

Oswald -On the rear spring bracket, the hole where the lock bolt goes in, that holds the pin in is broken out.
Bracket P/N 604912

thanks all, I think I have all this mostly sorted out.

And to JIMGMC, I'm aware of the damage to the spring mount. What you can see isn't the worst of the damage. The inner hole is no longer round, it has the shape of a paper clip. I've already sourced a replacement mount for that.