‘78 K10 Suburban Suspenders... er... Suspension!

[RyanAK]

Hey gang. I’ve owned my Suburban for nearly a year now and have immensely enjoyed daily driving this rig. Interstates, around town, long commutes to work, 500 mile trips to the in-laws, local state forest roads, and some two-track Jeep trails around our cabin. 18,000 miles. It’s everything I could have hoped for in a family truck. Kids LOVE it. Glad I went this route after the ‘71 C10 Suburban found a new home and the ‘11 Tahoe left me underwhelmed.



Anyway... with the exception of one hiccup that left me on the side of the interstate it’s been great. I’ve done small improvements and adjustments along the way while driving it every day. Doing new exhaust this weekend. But now it’s time to take a hard look at the suspension.

The suspension is stock. 7,300 GVWR. The truck rides pretty nicely, but there are some things that lead me to think it’s time to freshen up and maybe upgrade things. Shocks seem ok... but they’re unknown make and age and are probably close to needing replaced. There’s a pretty good gap between the two leafs of the passenger front spring and the front axle isn’t perfectly centered under the front of the truck. The rear (5 leaf + 1 flat helper) doesn’t sag much.... with an empty gas tank. Put 40 gallons in and it starts to drag it’s tail. (Tank on a Suburban is behind the rear axle...) One of the leaf pack clamps is gone on a rear spring. Bushings need replaced. Has the ‘Chevy Lean’.

So I think it’s time to address things.

And there’s this: I went all-in on the daily driver thing. This is my only vehicle. So my suspension plan has to get me mobile again pretty quick or I’ll be borrowing the ever fetching Mrs. RyanAK’s Forester. So I’m gonna prep and assemble everything I can and stuff the new stuff in systematically on evenings and weekends when I can. Front shocks some Wednesday after work... Rear springs and shocks on a Saturday... etc.

So I’m asking for advice on a strategy and parts selection. I think I laid out How the truck gets used pretty well above. Hauling right now is limited to two young kids, maybe 200-300 lbs of gear, a 100 lbs Wonderdog, a loving wife of perfect weight, and 40 gallons of fuel. Possibly a small camper or utility trailer in the future. Gentlemanly on the pavement but still capable for moderate hauling and light 4x4 work. I have new 265/75R16 General Grabber A/Ts (31”) at 40psi. 350/360/203(stock)/3.73. I don’t want to lift if I need to rework steering, brake lines, shock mounts, pinion angle, etc.

Here’s my current thoughts:

Front:
Used stock front (2-leafs) - $100
Re-arch - $60
ORD 1” zero-rate add-a-leaf (marginal extra tire clearance) $40
U-bolts - $45
Spring and shackle bushings (could use guidance here) $100
Shackles?
Bilstein 4600 shocks - $170
Total - $515

Rear:
Used stock rear (4+1 leafs from an 80-87 K10 Suburban ) - $100
Re-arch - $60
ORD 1” zero-rate - $40
U-bolts - $45

OR...

Add-a-leaf to existing spring pack - $100
U-bolts - $45

OR...
Hellwig EZ-990 helper/load-leveling spring to existing pack $110

Spring and shackle bushings - $100
Shackles?
Bilstein 4600 shocks - $170
Total - $515 or $425 or $380

So $895 - $1030 for something just a bit better than stock. Maybe. I certainly could use any advice if this is money well spent. This approach does allow me to buy and install over time as opposed to going directly to an aftermarket 2”-2.5” lift. Thanks in advance for any thoughts that come my way.

[blakeduren]

If it were me...
In the front..do all three pairs of bushings and ORD shackles. New shocks.
Or maybe if you can find 3 leaf front springs.
In the rear...custom ORD rear springs and new shocks. New bushing on shackle.

[LT7A]

You have a well-thought-out plan. Is the picture above most likely with an empty, full, or half full gas tank? The reason I ask is that the front already sits pretty high. I think ORD has a shackle flip for the rear that can gain you two and a half inches. That might give you a bit of a rake when the truck is empty but pretty close to the level when loaded. In my experience, Bilsteins make a huge amount of difference. The things I would consider adding to your list are Teflon inserts in the leaf springs and I think they even make Teflon paint. The idea is for the springs to retain their load carrying capacity but minimize the internal friction so that they can give over bumps.

[RyanAK]

Thanks, fellas. Appreciate the feedback. Couple questions...

Three-leaf fronts generally stiffer or same spring rate?

Do spring shops generally add a leaf when re-arching?

I’m having trouble determining if the available used 4+1 rears from an 80-87 K10 Burb are the same rate and spring pack thickness.

Rubber or poly bushings? I don’t want to rattle the teeth out of my head.

Worth it to get grease-able bushings?

I was under the impression ORD only offered lift custom springs... I’ll need to take a look...

LT7A - Thanks for the suggestion about the Teflon. I’ve never fooled with leaf spring replacement and wasn’t sure if there was anything applied between the leafs. And I really like Bilsteins and typically put them on all my trucks when budget allows.

That pic is with a half tank. Would a shackle flip need a longer rear shock or extended brake lines? The front height is about right, but I wouldn’t mind another inch if it doesn’t require steering or other mods. Curious if fresh springs will add lift alone...

Any plan is going to include new springs of some sort. The front passenger I can get my pinky between the two leafs. And the rears just seem tired. Plus I can’t be without my rig while I have the springs pulled to rebuild them. The options gotta be to pull off the old and bolt in new.

Anyone have thoughts on the Hellwig helpers? I thought that might help with sag when loaded without making the rear harsh and could be a good way to ‘dial’ out the Chevy Lean.

Ain’t this stuff fun?!

[Ryan Hubbard]

Ryan,

I have a 1990 V2500 (K20) Suburban that I have been driving for the past few years. My suburban was a 3/4 ton 4x4 that had the double shocks up front. It was a very rough ride. I worked with Deaver Spring ( my office is only about 5 miles from their shop) and I went with their 4" lift progressive rate leaf springs. I originally wanted only a 2" lift but they can't do a 2" lift with springs because the front springs are curved the opposite direction and a 2" lift would make the springs in the front flat.

I also went with a single front Shock and put in the Bilstein 5100 shocks.

This changed the ride completely, I still tow my car trailer without any problems but have a much more comfortable ride. Off road the Suburban handles the bumps and rock without any issue.

I did change the pitman arm on the front and did longer brake lines but I also upgraded to Wilwood Calipers up front.

The change over to the progressive rate springs was great.

[RyanAK]

Hey, Ryan. That rig looks great. I've never heard a negative about Deaver. I'm just not wanting to go 4". At most, I'd like my '78 to sit about as high as a stock K20.

But man... that is a good looking Suburban you got!

Cost is a consideration, but safety, comfort and helping with the sag are my driving factors. $1000 is doable, especially if I piece it together over time. First shocks, then springs. The ride is pretty plush unloaded right now, but I'm ok with things stiffening up a bit. Don't mind a 'truck' ride at all, just don't want my teeth rattling in my head!

The front I think I have set... stock springs and Bilsteins. Still thinking about bushing material, replacement shackles, or the ORD 1" zero-rate.

Rears... still up in the air. I like the idea of the progressive helper springs to eliminate sag and if I thought the existing leaf packs and bushings were ok, I'd try a set. But if I'm going to tear it out to replace bushings, I'd likely put fresh springs in. Bilsteins are a definite. Everything else is a thought exercise at this point.

Appreciate the input.

[1976gmc20]

Originally Posted by RyanAK

Hey, Ryan. That rig looks great. I've never heard a negative about Deaver. I'm just not wanting to go 4". At most, I'd like my '78 to sit about as high as a stock K20.

...

So how about just swapping to stock K/20 springs ?????

(not sure about a source, maybe a junkyard pickup?)

I went through all this thinking with our Suburban, but it needed so many different things and we really wanted a nice pickup again, so we ended up just trading it off for a 2016 K2500 HD.

I got to the point where, if I was going to change the springs to 3/4 ton, might as well just change the axles too ...

[RyanAK]

Oh, it could definitely spiral! I'm keeping this a K10. The reference to a 3/4 ton was just in regards to stance/height.

We all like photos, eh? Well... boring suspension pics but I always think more info is better than less.

Front Passenger showing gap between leafs.


Front Driver showing gap between leafs.


This is hard to photograph... but the front axle isn't perfectly centered under the body. Passenger tire protrudes quite a bit compared to driver's side....






Rear Driver.


Rear Passenger.


Maybe I don't have anything to be worrying about... but it's in my nature to worry. Especially since my 4 and 5 year old kiddos spend so much time in this truck.

R