What's going on here? Help with fabricated rear suspension

Just bought this 1997 Sonoma with only 24k miles on it. Factory 4.3 5spd zq8 G80 reg cab stepside with all the power options, if I had a time machine to go back and factory order an S-series the only thing I would change is getting a 98 dark grey interior.

I bought the truck in Vegas and drove it back to Long Beach, CA. The 23 year-old and his father bought the truck off ebay and were reselling it just a few months later, they know nothing about the truck (they didn't even know it had headers on it). They gave me the prior owner/builders number but he's not answering/returning calls.

The front end is Zq8 coils and 2" belltech spindles I belive, and it does look like a 3.5" drop. Rear looks about 4" drop. I was quite surprised when I looked underneath and saw what was going on. Leaf pack is only 2 leafs, if it is the factory ZQ8 spring then it's missing the overload and the smallest leaf. There is a 1" block, no zq8 sway bar, and this bar with heims ends that connects from the drivers side shock/axle plate diagonally to the passenger front leaf mount. There are HAL adjustable shocks, but it looks to me that they are just about bottomed out. I have no experience with these shocks, but it seems like they are too tall for the application? Or is that 0.5" - 1" of estimated stroke left good enough at that angle? Thoughts?

The back end actually handles decent, not soft, not kidney jarring on the road. I can't really get on it in a turn though because it has some cheap REV 20x9.5" wheels with not enough backspacing so the drivers sidewall will rub on the bed fender lip if you get on it around the turn, the tire shows battle scars already and needs to be replaced (i'll be stepping down to 17 or 18"s for better performance.

So what do you think about the shocks being so compressed? And what on earth is that diagonal bar doing? It's been so long since I drove a stock Zq8 to compare the rear to. I have a stock 00 zq8 Sonoma that ill be selling, but its a gutless 4cyl with incorrect and worn out shocks so I can't really compare it to that either.

that diagonal bar is a form of track bar, trying to keep the axle from swaying laterally under load.
I agree those shocks are at the very end of their travel, just check how much rebound travel you have before getting shorter ones (unless you want less rebound travel) as a shorter one will limit that
But it looks like your bumpstops have already been removed and I think i see witness marks of the axle (ubolt) crashing into the frame.
with the leafs so flat make sure the backside of the shackles aren't crashing into the frame causing binding either
If you want to maintain this ride height I would recommend getting a notch (I do not recommend the bolt-in halfround notch)
I assume someone removed the rear swaybar because it hit the new diff cover.
you already have the frame brackets, so you can find something to work pretty easily.


overall looks like a super clean chassis, should be fun once you can turn!

That really is a good looking truck.

Wouldn't the 'panhard'(??) bar being angled like that cause some weird axle motion during travel?

I have HAL adjustables on the rear of my truck. They are a good quality shock but I don't think they're going to do much with that limited amount of travel.

Wouldn't the 'panhard'(??) bar being angled like that cause some weird axle motion during travel?

since the front point is in line with the leaf, I don't think it'll be bad at all.
the only length change happens when the leaf section in front of the axle arcs, which isn't much.

plus a benefit is that it doesn't load the frame in a direction it wasn't designed by too much.
not an ideal direction or support, but i doubt it'll cause any major issues.

If you have significant axle wrap then you might notice a weird lateral movement but if you have axle wrap you have issues you want to fix already anyways.

There might be some axle movement, the current wheels are 20x9.5 (REV website says it's 0 offset which is 5.25" backspacing which should be perfect) but I need to pull one off and measure, I think it might be less than that cause there is a lot of wheel lip, and there is about 1.5" of clearance inboard of the tire to the leaf, but only like 0.25" from outside of tire to bed fender lip. Maybe the company used to manufacture a wheel with less than 5.0" backspacing

The drivers side sidewall has some battle scars from coming in contact with the bed fender lip (not rolled), So either there was enough body roll on hard right turns, or the axle was in fact moving. But then again I know zero history of the truck so maybe the tire rubbing was occurring before this bar was installed and this fixed it?

I don't notice much axle wrap or body roll with the current setup, but I haven't got on it hard in any turns since that tire is rubbing. I'm going to step down to 17" or 18" wheels, or 17/18 combo with the correct backspacing out back.

Green, you called it. The rear leaf shackles are already in contact with the frame, they cannot move back any further. Not sure how to remedy that other than custom shackles or changing leafs.

I like the current height, its about a 4" drop out back I think based on there being 2" between the top of the axle and the frame (doesn't need a notch it looks like, but I'm not opposed to doing one). There is a 1" block, so the leaf must be giving me a 3" drop. I have three options there it seems, switch to some belltech 3" drop leafs, go back to a full 3 leaf ZQ8 leaf back and use 2 or 2.5" worth of blocks, or lastly dearched or custom leafs from another spring shop?

Thoughts there?

As for axle, I'll get pictures later as im late for work, and it may just be how I backed into a driveway, but the passenger rear sidewall will not clear the bedside by 1/2", whereas the drivers side one looks like it clears by 1/2", so the axle is actually sitting half inch to the right it seems. It has some major chevy lean too, the passenger rear fenderlip is 1.25" higher it seems, I do have a full tank of gas at the moment.

I'll drive it around and park straight forward and get a picture later to show where the wheels are sitting vs the fenderlips. if its still bad I think the shocks short travel, the shackles binding, and the axle being offset to one side means I'm going to have to make some serious changes to the rear setup.

Usually unequal tire to fender clearance side-to-side in the back is due the box being slightly misaligned on it's mounts.

you might be right, I can tell the bed been off, hes replaced bolts with stainless hex cap bolts. It's also been undercoated and there are red polyurethane mounts.

It looks pretty even with the cab though, I guess I should double check later.


Now I'm having a smog problem. I passed the sniffer test, but my computer failed as it's in a "not ready" state. I haven't disconnected the battery, and I've driven it over 400 miles since i bought it so even if prior owner disconnected, it should be good now. However this morning I removed the airraid intake as I dont have the CARB sticker for it and airraid will take a few days to mail it. I threw in the stock airbox off my 98 blazer. I did not disconnect the batter as I didnt think it necessary and I didn't want to reset the computer. When I was driving to the smog station this morning, just 5 minutes away, I noticed my RPMs in neutral would hold at 1500-2000rpms. Like if I stepped on the clutch at 2500 rpm they would fall, but not fall to the normal 700ish idle. It stopped doing it within a mile of the station so I figured it was fine. I think the MAF must have got a different airflow reading, or even a colder IAT reading with the stock airbox since the airraid just sucks in hot air, and this possible made the whole computer reset its memory and restart tests.

I went and drove for 50 minutes, I triggered all the tests except evap (my gas tank was full) and O2 sensor heater. Smog guy says I dont need the evap to pass and the 02 sensor heater I googled the drive in procedure and apparently you have to cold start the car, let it idle for 3 minutes with AC and rear defroster on (I don't have one being a truck not a blazer), and that will trigger the test.

Got it parked in the shade hood open to cool off now. Will try again in an hour or two. What a PITA.

Time to start a Members thread for this truck, I'm going to have too many questions like this.

Could just be a loose air intake connection causing a minor vacuum leak. If a coupler pops off the intake, it will run like crap and won't be able to regulate idle so it could just be a minor leak somewhere.

axle not being centered, as mentioned it could be the bed, otherwise you have a convenient rod end to adjust with

Switching to ZQ8 leaves will gain you back some of the shock travel, but then you get the fun of a 2 or 3" block and the leverage it will have on the springs. Taller blocks could be more prone to axle hop/wrap. The belltech springs are soft from what I've heard and read, which is why I've stuck with the factory drop springs so far.

You also might be interested in picking up a bluetooth OBDII reader and using the Torque app. It lets you read available engine data, CEL codes, and even reset the codes. It can be quite handy for troubleshooting even if it isn't as powerful as a full tuner or OEM scan tool.

I've had the belltech leafs, they aren't too bad, but not firm either. I might look into having a set of leafs made by a spring company, though I'm sure that's going to cost a lot more than going belltech + 1" block or zq8s plus 2.5" of block

would a set of low profile cal trac bars help overcome having 2-3" of blocks?