1970 C20 has coils and helper springs

[Vance_cortino]

Happy Sunday, all. With the nicer weather, I've been able to start tinkering with the C20 again. Doing some engine bay tidying, and prepping to install the master cylinder and power booster setup I purchased from PICKEMUP back in the fall.

I was looking over all of my existing brake lines and hoses, and remembered that I have an odd rear suspension setup. I'm not sure if this was a factory thing, or another cob job from over the years and multiple owners.

Basically, this truck is a 350 with the SM465 manual, and an Eaton rear w/the No-Spin option, and coilovers/trailing arms. But there are also leaf springs added in with the trailing arms.

Was this a thing? Thoughts on keeping them or pulling them? The truck goes down the road fine as is, even if it does ride like a lumber wagon. But that's half the charm, really

Got some pics to show what I mean:

[factorystock]

By the SPID, your C 20 was originally ordered with heavy duty 3000lb rear coils which should have been enough. However, at some point in its life, previous owner wanted more capacity and added aftermarket leaf springs which were common items for sale back in the day. Optional factory style over load leaf springs on coil spring trucks were attached behind rear axle to the frame and arched to a point on the rear portion of the trailing arm. If your not hauling extra heavy stuff, you could probably live without them. If you want a great ride, the standard 2000 lb coils are the way to go.

[Vance_cortino]

Originally Posted by factorystock

By the SPID, your C 20 was originally ordered with heavy duty 3000lb rear coils which should have been enough. However, at some point in its life, previous owner wanted more capacity and added aftermarket leaf springs which were common items for sale back in the day. Optional factory style over load leaf springs on coil spring trucks were attached behind rear axle to the frame and arched to a point on the rear portion of the trailing arm. If your not hauling extra heavy stuff, you could probably live without them. If you want a great ride, the standard 2000 lb coils are the way to go.

Excellent info, thank you. I might end up taking them out and setting them aside just to see if I like the change in the ride characteristics.

[Steeveedee]

I'd check to see if you ever hit those overloads during regular driving. Maybe put a gob of something that will compress when those springs hit. Unless you have WHOLE lot of weight in the bed, I'm betting they don't engage. Of course, if you don't expect to really load your truck, take them boat anchors off.

[Vance_cortino]

Originally Posted by Steeveedee

I'd check to see if you ever hit those overloads during regular driving. Maybe put a gob of something that will compress when those springs hit. Unless you have WHOLE lot of weight in the bed, I'm betting they don't engage. Of course, if you don't expect to really load your truck, take them boat anchors off.

Yeah, I don't tow or haul with this, really. It's my nice weather cruiser and occasional building material hauler. Nothing I'd need all that extra for.

[Palf70Step]

My c10 has the overload/HD leafs also. Mine did not come with them originally, but were added about 15to 20 years ago for towing heavy trailer. They don't come into play till the rear coils springs of the truck squats a certain amount. They do not effect the ride at all under normal conditions.

[howzzzit]

Many years ago I installed a helper leaf spring on my 72 C10 with coils. I bought a six pac overhead camper and it was too much for the coils. Rode level and like a dream. Took the camper off and it was a bucking stiff nightmare. Like no springs at all. Sold the camper a few years later and enjoyed throwing the leaf helpers in the trash. Springs were Hellwig.

[Jim Boy]

My 68 came with the helpers 4-5 leafs very heavy. The PO ordered the truck just to haul a big camper and tow a boat for his fishing and hunting trips. When I bought the truck there wasn't a mark in or on the bed. When I did the truck I took the helpers off, still have them ,and installed the heavy duty springs again like it came with. I have had three L6 engines in the back and had no problem driving. The helpers aren't needed with the heavy duty coil springs, My two cents worth, better make that two quarters worth with inflation. Have a good one.

[67 twins]

Originally Posted by Jim Boy

My 68 came with the helpers 4-5 leafs very heavy. The PO ordered the truck just to haul a big camper and tow a boat for his fishing and hunting trips. When I bought the truck there wasn't a mark in or on the bed. When I did the truck I took the helpers off, still have them ,and installed the heavy duty springs again like it came with. I have had three L6 engines in the back and had no problem driving. The helpers aren't needed with the heavy duty coil springs, My two cents worth, better make that two quarters worth with inflation. Have a good one.

You need the heavy duty springs and the helper springs if you want that 7500 GVWR

[jayoldschool]

Keep them! No change on unloaded ride quality, and a big help with big loads. I have the factory ones on my 65 LWB C10, and they get used when hauling wood, engines, loads of top soil, etc.