By Chris Ritter
With the thought of reassembling my rear suspension on my mind, I recently gathered all of my parts to determine what I needed to replace and what I can reuse. Leaf springs — check. Leaf spring shackles — check. Shackle bolts — oh wow, a bunch of those are trash. U-bolts — oh snap, all of those look terrible. It is time to go on the hunt!
My first part to tackle was new U-bolts. While I suppose I could have made an argument that my originals could be reused, at around $9/bolt it is quite wise and cost effective to buy new bolts. Besides, I didn't feel like scraping and cleaning the old units. Assuming the U-bolts on my car are pretty much universal, I made a trip to the local NAPA store.
U-bolts are sized by providing three dimensions — A: the rod diameter, B: the width between rods inside to inside NOT center to center, and C: the length of the rod from its end to the highest part of the bolt curve. Oh yeah, that's another thing, U-bolts can have a round bend, semi-round bend or square bend. My bolt dimensions are 1/2" X 3-1/8" X 7" and they have a round bend.
NAPA was eager to help but didn't have the right bolt on the shelf. Some consultation with their computer followed by flipping through some old, thick catalogs produced "something that might work". The bolt they had available was 1/2" X 3-1/8" X 6-1/2" and they ordered me a set of four. I picked them up the next day and started flipping through my pictures of the car before disassembly — would the new bolts be too short? Absolutely. It turns out that when installed there were only 2-3 threads visible on the original units. While I would be able to get these 6-1/2" units started I would never have enough length to make them safe. With that knowledge I simply returned the bolts to NAPA and continued the hunt.
As I mentioned above, new U-bolts cost around $9 each pretty much wherever you shop. The big variable, however was shipping and prices ranged from $9 to $25 via UPS! The $25 rate was from a shop in New York and the $9 rate was from Ace Spring Service in Texas. Some phone calls back and forth between the exceptionally friendly "Anthony" at Ace were made and within days a fresh set of four properly fitting U-bolts were at my door.
This shows how far the U-bolts extended past the nut before disassembly.
A new U-bolt next to a recently retired bolt.
The second thing I needed to hunt for were shackle bolts. The threads on two of my shackle bolts were trashed and I had suspicions that the threads on my other bolts couldn't have been much better. These bolts are pretty darn critical too — if your shackle bolts come off there is nothing connecting the body to the rear axle and expensive noises will follow soon after bolt failure.
The bolts are pretty simple. A zerk fitting is attached to the bolt head covering a shaft for grease. The shaft opens at the center of the bolt where grease can be applied into the bushing that rides in the leaf springs. Plenty of grease here ensures a smooth and quiet ride.