i have 1999 chevy silverado w/6.0 liter 4X4. i am told buy the local dealership that in order to do an alignment on the truck they may have to remove the knock-outs which greatly increases the price. is there any way for me to tell if my truck still has the knock-outs or am i at the mercy of the dealership. i have heard that the new body style trucks don't have them but i don't know if this is true. any help would be appreciated.
My 1996 had knockouts. Since it was the first I had ever heard of this I was at the mercy of the dealer. I bought the truck in 02. When I brought it back for an alignment at the dealer I bought it from...(I figured what the heck...they were cheaper than Firestone...) they "supposedly" were never removed. Due to having to drop the truck off at my lunch hour, I was unable to get in there and look/learn myself what these things were/are.
Get in there, find out and look for yourself. I should have, and still to this day do not know what the knockouts are and if they were there of if I got took.
a $35.99 alignment turned into a $169 job.
Eightupman
Frame knock outs (partially upset frame metal) are used to usually
adjust 'extreme' front suspension caster, Or combined caster camber...
Upper control arm 'shims' are the first line of adjustment...
Both the shims & oval knockout pattern are located at the Upper
Front Control Arm Bolt Locations ( Two bolts per side)... under splash guard..
The upper control knock out surfaces (If used), can lay
either flat with the Ground, but are usually above a vertical
Spring dome bracket, on the UCA Bracket at the Front Wheel Center Line...
In effect... each Frame when assembled has 2 holes
pierced for the Upper Control Arm bolts (per side)... The piercing
operation also may upset the oval knock out metal to allow
for Addition Front Suspension bolt adjustment distance, beyond the use of shims.
The whole Upper Control arm can be slid via the knock out slots for major
re-alignment circumstances.. THere are 2 knock out slots per side....
Using a Knock out... Trades a small adjustment hole for a slotted hole..
where the bolt hole lays in the middle of the knock out (upset metal) slot.
The newer Chevy's are EASY. They have a plastic piece that you just pop right out and then you can do your adjustments. It's great. The older trucks like yours is different. Basically if you look at your Upper Control Arm Bolts, where it's mounted to the Frame, this is where the Adjustment it made. From the Factory it just has a hole for the bolt. You can't move the control Arm in or out on the front and back of the control arm. Usually there will already be Cam Bolts in place from the Factory, but it's not slotted. Usually if the Cam bolt Washer that's Offset its either straight up or straight down then it's never been screwed with so more then likely hasn't been slotted out.
Have you owned the truck since it was new? Have you ever had it aligned before and if so had it been slotted before? It's a 1 time thing. Once it's been slotted, any time after it can be aligned and you wouldn't have to worry about it, unless you only do 1 side of the truck.
Normally the person doing the Alignment would just make the Adjustments and then that would be it. In your case, the Upper Control arm bolts will have to be Removed, the control arm will be moved out of the Way, and then the Holes will have to be Slotted out, then everything put back together, Re-Measure everything, and then make the Adjustments. This is Extra work and time. So of course it's going to cost more. At least you can adjust your truck. A lot of cars and trucks out there you can only do a Toe set. No Camber or Caster Adjustments possible. Or you have to do some really funky things to get a cars Alignment right. Possibly go with Aftermarket Hardware to get it in Alignment. You can really get into some big bucks.
You can always just have them do a Toe set and then you get out of there cheaper. It depends on where your Camber and Caster readings are at. If you don't have a pull, and it's not going to cause your tires to screw up, a Toe set may be fine. All I can say is, when I have to do one of these trucks, I always hope it's a 4x4 and not a 2 wheel drive. A 4x4 is easier to do. The control arms bolt to the outside of the frame. On a 2 wheel drive they are on the TOP of the frame. It's easier to Slot out and Adjust on a 4x4.
Thanks! I guess I should have asked this question a while ago. I'll get out there and take a look at this stuff tomorrow.
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