batboy

iTrader: (6)

I've owned a 2006 Tahoe 4WD for almost 6 years now and love it. But, I never cared for the tires, they were something called Wildcat A/T Radial (255/70R16). I wanted a couple sizes larger, but could not initially justify getting new one since they were new when I bought the truck. That was over 30k miles ago, so I decided it was now time for new BF Goodrich All Terrain KO2 (265/75R16 which are 3" taller and 1" wider than old tires).

My little Tahoe also has the dreaded front end droop. I measured it to be 2.5" lower than the rear. I needed to do something about the saggy stance. I'm not trying to "level it" since I want the rear to be at least 1" higher for towing and hauling purposes. So, like almost everyone with a Chevy 4X4 with torsion bar front suspension, I tried cranking up the keys and got 3 full turns (1/2 inch). It looked better, but it rode rougher and handling was degraded. On top of all that, the front end was still 2" lower than the rear.

I looked at getting leveling/lift keys and did hours of research. I came to the conclusion that my torsion bars were fatigued and had lost a lot of its spring. Yes, torsion bars do wear out over time and usage. I blew out a rear shock last year (it started visibly leaking), so the back shocks were fairly new. The front shocks are shot too, so I had the bright idea of putting new front shocks on, new torsion bars, and getting an alignment--to properly supplement the new tires.

I ordered a pair of heavy duty torsion bars with the XM code (rated at 5638 ft/lbs). The old torsion bars were rusty and were flaking off layers of rusty metal, They were in sad shape and rusted solid to the control arms on one end and on the other end, the keys were rusted solid too. The good news was, I got the old front shocks off without too much hassle and installed the new shocks. That lured me into a false sense of accomplishment, so I proceeded with doing the torsion bars myself too.

At least I knew enough to get a good torsion bar removal tool. I got the kind with a loop and it worked great. Once the tension was released, I beat on the corroded torsion bars like they were redheaded stepchildren. Oops, forgot to mention that I was spraying PB Blaster onto the rusty parts too. I read more forum posts and noticed a lot of people had to remove the crossmember when everything was rusted. So, I did that, but still no go. Screw it, I had new torsion bars, I decided to cut the old ones off. I tried using a sawzall first. That tough spring steel torsion bar just laughed at my feeble attempt. I switched over to a 4" angle grinder with a cutoff wheel and slowly chewed through the bars.

Once cut in half I could finally get a solid hit with a heavy hammer and soon knocked the stubs out of the control arms. But, the keys are still rusted solid inside the rusted crossmember. Screw it, I'm tired of messing with rusty crap. I'm going to cut off the keys and use new keys. Question: since I just want to bring the front back to OEM height, should I get stock GM keys or get leveling keys? I'm assuming with new heavy duty torsion bars, a GM key will be enough, right? I do have a pair of Rough Country 1.5" to 2" leveling keys I can try (bought a while back before I got the new torsion bars).

silver-mod-o

iTrader: (15)

You need to shelve your whole line of thought and put coil-overs on that thing and enjoy your truck. Fighting those torsion bars is an excercize in futility. They'll only ever be just "so" good. It will be like having a new truck on proper coil-over shocks. Our sponsor Atomic fab sells the bracketry to make it happen.

batboy

iTrader: (6)

Good morning, it's a beautiful day for December. Once the day warms up a bit, I will go out and try one more time to get the rusted keys off the remnants of torsion bars. I soaked them good with PB Blaster again last night.

Seems like these projects have a habit of snowballing. Since I took the crossmember off, I see it's really rusted bad too. Also, the bushings that the crossmember attaches to are in sad condition. The dealership told me the bushings are not sold separately (not true). They told me I had to cut off the old bracket and welded on the new bracket.

Chevy pickups have this bracket attached with four rivets that you chisel off and then use hardened bolts to reattach the new bushing bracket. Not so with the Tahoe. What freakin' genius approved welding on a part that will eventually need to be replaced? I don't have a welder, so that's not an option for me.

Google is my friend, so I searched online for a couple hours and found that GM does have a press-in replacement bushing that will work after all (part # 20829013). It does require removing the old bushing and pressing the old one in. I found a guide (with pics) that shows how to do this on another forum. Not sure I should post the link here though.

Also, Dorman has a replacement bracket/bushing that can be welded on or maybe bolted on if you drill holes. (part # 905-507). But, since my Tahoe has a boxed frame, bolting it on would be tough. I decided to try the GM press-in "torsion bar mount insulator". If you google GM part # 20829013, you'll find Rock Auto and Amazon and a half dozen other places sell this part cheaper than the GM dealerships.

Ok, while I'm waiting for it to warm up a little outside, so I can get back to work, I'll post some photos. Here is what the Tahoe looked like when I took it for a test drive in Feb. of 2012. It's a retired Nebraska State Police vehicle with cloth seats up front and vinyl seat in the back. It has the Z71 off-road package (with skid plates and heavy duty suspension), electric cooling fans, 4.10 gears, locking rear diff, etc.



Here's what it looked like for the last 5 years (I painted the bowtie black and installed a bull bar). For performance, I put on headers and had it tuned.



Here's a photo from a few days ago when I got the new tires. Gotta love the aggressive look of those BFG tires. This shot was after I cranked the torsion bars up 3 turns (1/2" lift). I'll take and post a couple of pics after I finish installing the new torsion bars.

batboy

iTrader: (6)

I hear you and I agree coil-overs would be great. But, at this point I'm committed to the torsion bar setup. If I knew it was going to be this much hassle and expense, I probably would have looked into other options. Thanks for the input, maybe your comments will help others decide which path to take.

Atomic Performance

Just saying, this bolts on in a few hours and rides way better than the torsion bars will at any height you want

This is a truck with a lift kit installed, but your truck would like the same, jut with a shorter shock and spring. You can also leave out that crossmember (or leave it installed if you want) since it wont be needed anymore.

Total for everything including double adjustable Viking shocks, springs, thrust washers, spanner wrench, and brackets is typically $850-$950 shipped. I just need you to measure from the center of the lower shock bolt to the top of the frame shock perch with the truck on the ground at the ride height you want to properly spec out what shocks and springs you need.

Feel free to PM me here or send me an email at atomicfandp@gmail.com if you have any questions!

batboy

iTrader: (6)

Sweet truck and a nice coil-over setup. I'm assuming the springs can be found in a variety of heights and spring rates? I custom made front coilovers for my GTO using Mustang struts, Strange coilover kits, and QA1 springs, so I have dabbled a bit with coilovers.

Back to my thread... I got one key off and the second one is starting to move back and forth a fraction of an inch (that's how the other one started). I ended up buying a pair of Dorman part # 905-507 torsion bar crossmember mount bushings from O'Reilly Auto Parts (identical to the OEM bracket and bushing). I was able to press the new bushing off the "weld in" bracket. If I can get the old worn out bushings off the existing frame brackets, then I'll be all set to start reassembling. My plan is to press the bushings on using large fender washers and a bolt. I've done this method on other cars before and it worked.

Ok, break time is over, back to work.

UPDATE: The disassembly is finally complete and it's officially going back together. The torsion bars and crossmember are in. Since I got the OEM keys out undamaged, I'll try them first. I cleaned up the keys and slipped them into place. I'll use the unloading tool tomorrow to set the pre-load and to install the adjuster bolt. Shouldn't take too long to finish up. Also, the bushing thing worked (discussed earlier). The only reason I didn't get the GM replacement insulator was because I'd had to order them and wait until Tuesday.

Tig

iTrader: (2)

Damn Atomic, that looks great.

Is it the same measuring process to drop a 2wd?

Atomic Performance

Yes, I like to use Viking springs when I can since I am a dealer for those and can get guys a good price on those with the shocks, but generally any 2.5" spring will work. I have used Viking, Hyperco, PAC (who I am also a dealer for), Eibach, and King springs.

Tig, short answer is no (2wd is easier, just measure from center of wheel straight up to fender), but I will send you a PM as to not ***** up batboy's thread.

Chubbs878

Looking forward to the results batboy. New TB-crossmember bushings and brand new TB is a serious foundation to the front susp'n rebuild. The HD part# does pertain strictly to the 1500 chassis correct?

You are doing good work here. My only suggestion is to replace the urethane/plastic jounce stops (if needed) and see to it these are making contact with the lower control arm as you set up your ride height on the TB adjustment bolts as these jounce really are essential to vehicle handling and hard braking. If you find the original TB keys lacking for height & swap in the modified units, please do some internet searches on this beforehand to find the various results to be obtained. You don't want to use them at their full capacity for a number of reasons, which you should have no trouble finding. Those HD bars will give a firm ride & maxed out TB keys (aftermarket version) will increase the harshness exponentially. If you haven't seen what it does to the upper control arm, CV driveshafts & TREs, Google images and "that other forum" will yield many examples. I also hope that you have access to a reputable garage that is known for its alignment techs. Some don't know what to do, while others who are experienced usually have no problems turning out modified trucks. It's going to need a complete adjustment soon as you get it back on the ground; I wouldn't drive it to work much less the beer store until someone has worked their magic on it. I swapped in some leveling keys torqued pretty lightly & the camber \\--+--// was super ugly. Good Luck with everything and keep researching.

batboy

iTrader: (6)

Thanks for the info. Is there a way to actually test the bump stops? I looked at them and they visibly appeared to be still in decent condition.

Regarding alignment, yes I will definitely get an alignment. My first post mentions I planned to do an alignment afterwards. Unfortunately, my go-to shop for alignments closed down last year. The tire shop I'm going to try is a locally owned, family ran business. They have a good reputation and seem willing to work with folks.

I'm not sure what you mean. The only part numbers I listed were for the crossmember mount/bushing. Yes, those were for 1/2 ton. Not sure if they can be used on the bigger trucks or not.

The torsion bars I'm installing have the XM code while most of the "regular" Tahoes use the lighter duty XL code t-bars. Remember, Tahoe torsion bars are 52" long which are 2" shorter than the Silverados. Also, just a reminder, torsion bars are right and left. There is a L or R along with an arrow showing direction of rotation stamped onto the butt of the bar. That end goes into the keys. So, new T-bars must be installed carefully to ensure the orientation is correct.

Here is part of a torsion bar chart I found floating around in cyber space.

15048307-LH (code XK) (Max torque 4553)
15048308-RH (code XK) (Max torque 4553)

15048309-LH (code XL) (Max torque 4626)
15048310-RH (code XL) (Max torque 4626)

15712407-LH (code WX) (Max torque 4863)
15712408-RH (code WX) (Max torque 4863)

15048311-LH (code XM) (Max torque 5638)
15048312-RH (code XM) (Max torque 5638)

15058267-LH (code YH) (Max torque 5913)
15058268-RH (code YH) (Max torque 5913)

15712409-LH (code WY) (Max torque 5913)
15712410-RH (code WY) (Max torque 5913)

15528957-LH (code GG) (Max torque 6709)
15528958-RH (code GG) (Max torque 6709)

15528959-LH (code GH) (Max torque 7161)
15528960-RH (code GH) (Max torque 7161)

15712411-LH (code WZ) (Max torque 7267)
15712412-RH (code WZ) (Max torque 7267)