The Stovebolt Site Forums The Shop Area Engine Shop Rear axle pivots- Help me understand

After seeing the wear on the shackle bolts and bushings and the spring eye bolts on the chassis of my 1952 3100 I was surprised at the condition of the rear axle pivots.
The rear shackle bushings had worn completely out and the threaded pins had almost no threads. The spring eye bolts were worn about halfway through.
My question is why don't the rear axle pivots show this kind of abuse. There is no lubrication to them and the two bolts appear to carry the entire rear weight of the truck. I appreciate that there is limited movement compared to the springs and it is rubber cushioned. Why don't these wear more or require lubrication?

Chuck

Maybe I'm missing somthing but what are rear axle pivots?

Pete

Part # 5.403?

I have a picture posted of mine welded up,when I converted to open drive line in the suburban"somewhere posted on this site".There is a lot of rubber bushing in each side,maybe this is why.

Tim

Are you asking about the pivot point where the spring attaches to axle? I am restoring a 46 and I had a machinest remove .101 thousands off one side of the clam shell (where the "U" bolts attach to the axle). The axle housing had ovalized from wear. Mine has zrek fittings to lube this area. I found however after reassembly the grease does not appear to get all around that area. Glad I greased it with wheel bearing grease.

That is the pivot I am describing. On my 1952 there is no provision for lubrication. There does not appear to be any wear on the bolt or sloppiness in the bushing. Unless someone has a better explanation I will assume that the rotation of the axle housing is very small unless there is major spring compression or extension. Without much rotation the rubber cushioning probably keeps the bolt from wearing despite supporting the weight.

Chuck

If it's tightened properly there's no movement at the bolt. The bolt clamps the inner steel sleeve tight against the housing. The rubber simply twists to absorb the small amount of rotation, so nothing wears. Rubber control arm bushings on independent suspension systems work the same way, but they wear out because there's more movement involved.
Jerry

Thanks for that info Jerry. There was so much crud and rust in there I didn't realize it was fixed in place. That rubber must be getting a little hard by now but I do not find anyone offering replacements. Does everyone using a stock suspension just keep using them?

Chuck

If you've got bushings that have hardened to the point of being brittle, there are probably plenty of good-condition used ones available from people who have converted to open-driveline systems. Try a request in the "Parts Wanted" forum, and you'll probably come up with a lifetime supply free, or at least inexpensively. As long as there's a little flex left, a good cleanup with a stiff-bristle brush and a strong mixture of hot water and dishwashing liquid, followed by a light application of brake fluid to keep things slippery without petroleum-based oil deteriotrating the rubber should get you back in shape.
Jerry

Actually I just assumed the rubber was hard after almost 60 years but I do not know how it compares to new. The rubber is not brittle at all or cracked so I guess I will use them. I was surprised none of the usual vendors sell replacements.

Jerry, thanks again for the explanation of solid mounting. Having not yet reassembled one of these setups I didn't realize that. I hate to admit how much time I spent trying to figure out how it could look so unworn. The answer was starring me in the face but I didn't consider that all the rotation was in the rubber. Makes perfect sense now.

Chuck