GMT800 suburban rides like crap!

[greasyfingers]

A week ago I bought an 03 Z71 suburban with 200k at a fair price. I/we needed a back up vehicle while I rebuild the transmission in my 2000 super duty. It needs some small repairs; tune up, cooling system flush, stepper motors, t case rear seal...

What really bothers me is how it drives/rides. The steering is numb, the brakes are over boosted, and the suspension is WAY too soft. It floats all over the place, tons of body roll, and bounces for a block after hitting a dip. I drove several suburbans before buying this one and they all ride the same. At first I thought no big deal, it just has a softer suspension that what I like, what I'm used to. But after diving it daily for a week I can't stand it!

It looks like my only option for the front end is to preload the torsion bars some more or get ford keys, and a different sway bar. I haven't found an option for the rear. Does anyone know if 2500 coil springs would fit or have any real improvement? What about the sway bars?

 

[cyclic]

Start with some new quality shocks, also look at the front "jounce" bumpers (bump stops).

 

[Roody]

I believe the guys on Z71Tahoe-Suburban and also on the Avalanche forum recommend Bilstein 5100s. I know there's sway bars out there but the company name is slipping my mind, I'm sure with some quick research on the CAFCNA you can dig up what brand it is...

 

[greasyfingers]

The shocks were replaced not too long ago. The truck came with a box of maintenance logs and receipts. This isn't a shock issue it's the low spring rate. Once I figure out what springs to go to, and height difference I'll address the shocks. I'll likely go with the 5100s. That's what I have on my super duty. I was hoping the 2500 sway bar could work so I could grab one out of a junk yard, I really don't want to pay the Hotchkiss prices. Hell, I might even make one. I made one for my buddy's fox body

Sent from my SM-N910V using Tapatalk

 

[Martinjmpr]

There's a guy over on the Tahoe/Yukon forum who will sell you a kit to swap out your T-bars for coilovers if you want. Pretty reasonably priced, too, I think the kit is $350 or so for the top mount (weld/bolt on to the frame) and then you source your own springs and shocks. One of our members (Geronracing) just put this kit on, you may want to shoot him a PM and see what springs he went with and how he likes it.

 

[Burb One]

I swear this weekend I am going to do a write up on the coilovers... Long story short, completely changed the truck.

Greasy- I have been reading that after years and miles, the torsion bars start to lose their strength. I always felt my GMT's to be over sprung (stiff in the front) and caused cowl shake. Maybe time to search for some lower mile bars or HD bars?

 

[rayra]

Don't know what to say to the OP's highly subjective anecdotes. I'm experience nothing like it in either of our Z71 GMT800 vehicles.

 

[Regcabguy]

Multiple rebound indicates a lack of dampening. I'm with the guys on the Bilsteins for a start.

 

[Burb One]

Multiple rebound indicates a lack of dampening. I'm with the guys on the Bilsteins for a start.

Misread the "bounces for a block". That part is definitely a dampening issue. Maybe there was some cheapy shocks put on and they already bit the dust? I bought a miata recently and it had some "recent" cheap shocks on it. When I switched them out, I couldn't believe how bad the seals looked on them, and that was in CA weather/ environment.

I'd agree to start with the Bilsteins, and then go from there.

 

[2004 lb7]

Go for new shocks our Suburban did great on gravel roads with Bilsteins.

 

[thethePete]

You need more shock. Soft springs don't make it bouncy, or even wallowy if you have enough shock. Cognito makes solid Chevy steering stuff, check them out. Also, at 200K, I would consider replacing the steering box, and springs for that matter. Springs do wear. So do steering boxes.

By the sounds of your complaints with the ride, I would skip the Billy 5100s and step right to a Fox 2.0 or equivalent. It will cost you a little more but you'll be much more satisfied with the results. Spring for the resis for the rear, so you don't have to worry about shock fade with a full load in the rear.

 

[rayra]

Upping the shocks just masks a wear issue. And puts all the load on just the (now much more expensive) shocks. With 200k mi on it you need to replace all the bushings to liven up the ride. Stabilzer bar bushings, end links / bushings, swing arm bushings, new torsion bars. Trailing links. And a replacement set of Moog rear coil springs is <$60.
130k on my '02 Z71 K1500 Sub, 170k on the missus' '05 Z71 k1500 Tahoe. *** on the sub is sorta dead. Worse since I swapped in the missus' old rear shocks, after I put new on hers. Hers is mostly highway miles and is still firm and stable, drives like new. And there's no wallow in either.

I've changed her shocks and front end links. Changing mine with a Rancho suspension upgrade / minor lift. Soon to change the end links on both, and likely ball joints on both vehicles, her rubber boots are blown. .

And frankly calling the Z71 springs 'soft' is horse crap. They sure don't start that way, and ours STILL aren't. If the OP BOUGHT the one with 200k, I have to wonder what the mileage was on the others he test drove, that led to his blanket statement. I think he's completely misunderstood their designed ride, based on a sample set of terribly clapped out rigs.

At a guesstimate, and doing most of the work oneself, all the worn out factory suspension bits could be replaced at well under $500. That would be where I'd start. And I certainly wouldn't start at throwing a set of shocks that cost that much onto that worn-out heap, without first fixing the underlying issues.

 

[BigSwede]

That much bouncing is a shock issue.

I would try replacing the bushings on the sway bars, you'd be surprised how much that tightens up handling, and it doesn't cost much.

 

[Tazman]

Bilstein 5100s and stiffer sidewall tires was the solution to my GMC handling issues. When stock it had an almost scary handling issues. When the tires needed replacing I used a level up on load rating and put the shocks on. I can not believe the difference. It is a completely different rig.

Just my 2c.

 

[rayra]

rockauto.com has GMT800 stabilizer bar bushings for about $2 each.
http://www.rockauto.com/en/catalog/...380327,suspension,stabilizer+bar+bushing,7624

front end link set is about $14, I just did those on both our vehicles a couple weeks ago.

Rear end link are $13 / side.

Upper and lower control arm bushings are about $20-40 a side depending on brand selection.

Rear upper and lower arms are about $50 a side.

ball joints are $20 a side.

If you can do the work yourself you can refresh the whole damned thing for very low cost.