rough ride - rear suspension does not flex

[plow_truck]

Hey all,

It's been a while since I've posted anything. I've made a little progress on this truck but its still pretty rough.

In the last two years I've replaced the power steering pump, the carburetor, the gas tank, the radiator, and the king pins. Now it doesn't have water in the gas tank.. doesn't leak radiator fluid, and the steering doesn't bind up!

Last week I took the sander off and took her for a short drive (maybe 10 miles). The suspension is in rough shape. The front has a bit of give but the back has nothing. Also, front and rear shocks are new.
Does anyone have thoughts on:
1) this suspension is shot
2) how to achieve some degree of ride quality and support a one ton load capacity (I've got a sander), its probably 1000lb empty

On topic #1 I'm thinking that the main spring is too flat and that its real bad... since I'm riding on the helper springs with no load... I'd think that there should be some real load at least 1000lb if not more before the helper springs are into play.

On topic #2 I'm specifically wondering if it would be reasonable to replace the springs and eliminate the  helper springs and replace them with timbren springs or something like that. I realize there are a lot of options, there are places that could recrown the springs, there are airbags and different helper spings in addition to different spring packs...

Any thoughts?

Thanks,

Jesse

[plow_truck]

I think what I'm leaning toward at this point is to use the lighter (2600 lb) 9 spring pack and the lighter k30 helper spring (its rated 1050 lb and is 1 spring).

Its not clear to me what these weight ratings mean... are they indicating that the rear axle can safely support 2600x2+1050x2 = 7300 lb? If so that is plenty. I could imagine the rear axle might carry 4000lb including the bed and so I should be able to safely put about 2000lb on it. If that's the case then I think this spring setup makes sense.

Really there are a lot of options and I'm not looking forward to the install so I'm trying to do my homework so that once the job is done things work well and hold up well.

The springs on my truck are probably from the original cab and chassis frame that supported a really heavy body and so lighter k30 stock springs will be better fit for me... Whether its a sander or something else the truck does well to have a weight on the bed once the plow is installed (to act as a counterbalance)... but I won't fill her up with 3 yards of sand.

[Mr Diesel]

I would not put a lighter spring pack on it. Looks like it hauls plenty of weight, just keep it as GM designed it. Those existing springs look completely worn out. A lighter spring pack will wear out faster too.
1 ton trucks don't ride soft. That is the nature of a heavy old work truck.

[berserk]

A stock replacement for a K30 is 8+1, I would buy a set of those and then add helper airbags. The truck would ride WAY better unloaded then when you have heavy load use the bags to level it out..

[plow_truck]

Thanks for the replies

Mr Diesel: I'm going back and forth on this. I certainly don't want to go too soft. I think the spring pack I have now (even new) is for a service body that get loaded up real heavy and I'm thinking that even a c30 dually dump body usually has the less stiff spring and a single helper spring not the 6 leaf helper.

I do plan to put a flatbed and a hoist for a hydraulic dump in place but I never plan to run dual rear wheel... I'll always have to be moderate about loading. I'll be happy just to put a ton on the bed and I've got no plans to carry gravel long distances. There's a million reasons that it just doesn't make sense for me.

Don't get me wrong about my goals. I'm not looking for super smooth ride quality its a work truck. I've got 4.56 gears and don't like driving over 40 mph. At present hitting a little bump at 40 gets you thrashed. I think you see that in the pictures because unloaded I'm sitting on the helper springs.

berserk: I'm afraid of airbags because of the plow. I know people do it but I'm concerned that I'd tear them up or something... I basically want to keep everything as stock as possible but at the same time sometimes aftermarket stuff is totally warranted. So its not what I'm thinking now but I haven't ordered anything yet. I plan to get stuff on order this week.

Does anyone out there have pictures or descriptions of k30 of c30 with a dump body... where they like the spring setup they run? I would appreciate any input.

Thanks again

[plow_truck]

I went to a place that specializes in truck springs and truck equipment yesterday. I was able to get some help on what spring pack to buy and what helper to use. The guy who helped me recommended the 22-547 springs and a timbren helper... so that's what I went with.

There is a risk that I'll overload these springs and regret it but he thinks I'll be fine as long as I don't leave a heavy load on it for extended periods. He thinks that the timbren is better than the leaf spring style helpers so I figured I'd go with that... The timbren price is way too high, but honestly as long as they work well and I don't have to reinstall stuff next year the price tag will become a distant memory.

He felt like the 22-547HD spring would be too harsh anytime I'm unloaded completely... that they should be used where the truck body is real heavy like a service body or where the sander doesn't ever come off.

I brought all the parts home but my weekend kind of blew up so I won't be able to install until next weekend (at the soonest).

I'll update once I install.

[plow_truck]

It took a while but I did complete this project.

I finished up the end of September and then needed to deal with a leaking pinion seal on the rear axle.

As far as the project of replacing the rear springs it incidentally involved:
a repair to the rear brake line
I decided to install timbren helpers on the front axle (the old ones were really chewed up)
I bought a cordless electric impact wrench (I don't have room for a big compressor)
I had to replace the main spring hangers (the ones toward the cab)
replaced the fuel sending unit and added a vent line

As expected, it drives a lot better.

pictures here:
https://photos.app.goo.gl/VFRzkAXCDRUYjx4p8

[JohnnyPopper]

It looks surprisingly good compared to the shot out old ones.

They looked like they would break at any moment.

Glad you got the results you wanted