The Stovebolt Site Forums The Shop Area Driveline 1946 1/2 ton - replacing front springs

Been driving my '46 since 1985. I finally broke a leaf in my driver's side front spring, and the passenger side is looking pretty tired too. I've got a 235 so back in the late 80's when I last messed with broken leaf springs, I had them add an 8th leaf instead of the 7 that's normal. Going to do that again. I'm in the process of removing the springs, which seems pretty simple. My question is whether I need to torque the U-bolts back on when I put the rebuilt springs on. If so dry torque to what? Tha nks for any advice.

You definitely need to torque U-bolts. In fact most spring shops recommend NOT reusing U-bolts. I don't know what the spec is for a '46, but the spec for u-bolt torque for AD (47-53) 1/2 ton trucks is 75-90 ft-lb. I would suspect that a 46 would need the same. But someone will likely come along with a definite torque number for you.

Just replace them, they stretch when torqued, and the more times they come on and off the more they stretch. Trailer shops have the 1 3/4" u-bolts.

And retighten them after first several trips.

Ed

Right now I'm wrestling with getting the big bolts at the rear of both springs off. They are ON THERE, and don't want to give up! Thanks for the advice on the U-bolts - I'll replace them.

OK, got everything apart and the springs are really bad. Cracked leaves on both sides. Lucky to identify the issue at home and not on the side of the road. I took them to a local spring shop that used to fabricate springs. They don't anymore. No point in trying to rebuild these - looks to me like failure from metal fatigue. I've seen new springs on a couple of antique parts sellers, but I don't know where they're made. About $250 a pop. I've had bad luck with some Chinese repro parts in the past - substandard metallurgy. Do any of you know of a good source for springs? I used 8 leaf springs when they were replaced back in the 80's (usually 3/4 ton application). I'd like to replace with the same. Thanks for any ideas or leads you can provide.

Eaton-Detroit


https://www.eatondetroitspring.com

Made in USA

Thanks, Otto. These are a bit more expensive than others Ive seen, but I'm willing to pay more for American-made quality parts. Had the truck since 1985, so it's way too late to cheap out now. Guessing shipping is pretty expensive as well.

David, I just noticed you live in Decatur. I also have a Decatur address, although I live in the East Atlanta / East Lake area off Flat Shoals road.

Where are you?

I'm off North Druid Hills Rd. Looks like you've got quite a collection. Let's get together and drink a beer sometime.

I have springs made by Detroit Spring under my '37. They made custom spring rates to match the weight of the truck, it rides way better than it did with stock springs, I don't use it for a truck, just for cruising around. I was willing to pay more for custom made, I know they make them in Detroit, no idea where they get their steel from.

Joe

I had springs made by them. I have an AMC Pacer front suspension and I wanted a new coil springs, 2-inch lowered. What I did not know was that were already 2 inches shorter and they took 2 more off. It would scrape the center ridge on a gravel road. I don't think they made it right but I do have the original length now.

I know your post was for46 this does not go that far.. Maybe they are the same.

Checked my old parts catalogue and the 46 and 47 springs are not the same, unfortunately. Real shame because the link you sent has them for a 47 for about $175 each. Eaton/Detroit chargs $295 each - close to double. Yikes! Plus $120 to ship 2 of them. Anyone else have any suggestions? If not, guess I'll have to swallow hard and pony up.

You might connect with Hotrod Lincoln on here

If you have a local spring shop, see what they can do. I bought mine locally, because shipping to Alaska is crazy expensive. Their price was less than I could buy directly and get them shipped to me.

David,

Here is another source for replacement front springs for 1936-46 Chevy and GMC 1/2 Tons, including an 8 leaf option, for significantly less cost than the Detroit springs.

No idea what shipping is as I didn't go down that path, but this looks like a much less expensive "pony" to invest in - lol.

Dan

When you decide what you want to spend, ask about the spring rate. Since they list them for '36 -'46 they may be generic and not right for any of them. Spend some time at the GM Heritage site looking at the information packets for each year of truck. The '37s used very heavy spring rates, almost twice what the '46 uses. I had a new set of stock springs for awhile, it was so stiff you couldn't stay in the seat. I had it down to 4 leafs out of 7 before it road decent, thats when I went to Detroit Spring. The deflection rate is what you want to look at. Deflection rate is XXX lbs to compress the spring 1inch, less weight, softer springs, better ride. It helps to know the weight on each axle or even each wheel. I used four wheel scales I borrowed from a dirt track racer. Once each corner was weighed, I put the chassis on stands, unhooked the shackles and shocks, and weighed each axle assembly. This gave me the weight of just the truck ( sprung weight ) and the unsprung weight of the axles, tires, brakes, shocks, and 1/2 the springs. A good spring shop will know how to use the information.

Joe

Great information, all. I really appreciate all the input. I talked with the folks at Eaton-Detroit yesterday. Man, they really know their stuff. Got a woman on the line that her daily driver was a 1950 Chevy 1/2 ton and she was a wrench as well, doing her own work on it. Although their springs are darned expensive, they a custom make for each order to OEM spec. When you order a spring for a 1946 Chevy, that's exactly what you get. Still mulling this over, but it's a job I only want to do once, so it would be great to get the right parts the first time around.

I found the same thing when I talked to them.

Can't go wrong with the springs spec'd by the people that designed the truck. Your pictures indicate that it's an original truck and not a custom hot rod so no need to second guess the designers.

Yeah. I pulled the trigger on the Detroit/Eaton replacement springs. Known quality, made in America. Quality is long remembered after price is forgotten. 3-4 weeks to get them - new U-bolts as well.

Good choice. Also, if it doesn't work out, you can take a 5 minute drive down the road and beat me up for suggesting them!

I got bit by the "might as well" bug. Waiting on the springs to be delivered and thought, "Bet those oil pan gaskets could use a replacement while it's easy to get at it." Put on in 1986, they were like potato chips. $12.50 for the gaskets and $12 for a tube of Permetex Super High Tack. Can't beat it. Got the pan painted too - nobody cares but me, but it's real pretty.

Can anyone tell me how much to torque the large spring end bolts on reassembly? They thread into one side of the spring mount and then have a large nut and lock washer to keep them from rotating out. I'm guessing you torque the bolt in first, then torque the nut and lockwasher on. Any knowledge on this would be really helpful.

The bolt requires virtually no torque
Because the spring isn’t suppose to be tight at all
There is a gap by design and sometimes folks like putting rubber or foam washer in that gap to keep the spring eye bushing cleaner
Bottom the bolt snug-ish
And the nut is the lock the bolt in place
The nut can get much more torque I don’t have a spec. I just use my gut feel
The bolt is acting like a pin there is almost no lateral forces on the bolt so it doesn’t need to be tight
If you try to tighten it you might break the spring mount
You can always tighten it more if it comes loose (it won’t)
But if you break that mount you will be sad
-s

Thanks 2ManyTrucks. I kind of thought that, but wanted to be sure. Looks like the big nut and lock washer are just a lock nut to keep that bolt from turning out. Just got an email from Detroit Eaton springs. Looks like they're about to ship. I will report.

Springs and U-Bolts came today. Very nice - big "Made in USA" sticker on them. Detroit-Eaton were great, sending me progress reports. Surprised me that they had already set the rear bushing and the front shackle pin. Checked everything for fit and it was spot on. I got them cleaned up with a good acetone rubdown and then shot them with 3three coats of black paint. Hoping to reassemble tomorrow. I will update.

Springs in and retorqued after 50 miles. Truck sits about 1 1/2" lower in the front than it did before, but I had 8 leaf springs on the front and replaced them with OEM 7 leaf springs. Truck handles fine and rides a bit better, but I did bottom out going over a speed bump, which I never did with the heavier springs. I'll change my driving habits and be a bit more gentle since I'm not carrying any loads to speak of. Generally pleased with the Detroit Eaton product, but it was pretty darned expensive. That said, reassembly was a snap with the springs fitting perfectly.

Sounds pretty good. Since you'll not be hauling heavy loads, you'll probably like the slightly softer ride.

Ease of installation is always a plus. It was nice to have the bushings installed at the factory.

Post t some pictures of your truck with it's new stance.

Just curious,
did you really bottom out brand new 7 leaf springs or did they just transmit enough energy thru the chassis to stress everything so it felt like it did?
Seems that would take quite a something (hole) to hit to get bottomed out on new springs, certainly not an expected everyday experience….

Chuck