scott2000

Thank you! So you're saying,if my Z height angle was correct when I measured while the control arm was jacked up, then even though when I put the wheels back on and the z height changed 2" (6" to 4") , that's just reflecting the different load? Sorry, I know I'm overthinking this. Yes. I understand the measurment It's just in my Service manual (1993 Sierra,Yukon,Suburban Crew Cab and 3500 HD) it says nut must be tightened with the control arm at z Height. Same with the control arms themselves and some other items. I should have mentioned earlier that I never checked the Z height before removing any suspension parts. I didn't learn about it until going to put things back. Obviously I didn't have any way to check when there were no parts so, I lowered the torsion keys to what was in the manual, left the upper and lower ca nuts loose, and jacked up the lower ca to get the z height as was in the manual and installed the upper and lower ball joints to both arms and the knuckle. I think this may have been a wrong way to go about it but not sure. I then put the axles in and the tires back on, and put the truck on the ground. When I measured the z height, it was off by 2". So I adjusted the torsion keys to get the z height where it is supposed to be and torqued down the control arms while it was on the ground. I've since put everything else back in, shocks , tie rods, etc. I noticed I now can't achieve z height with the truck on stands and jacking up the lower ca but, I can get enough of an angle to do anything necessary. Can get it to about 7" before it'll lift of the stands . I don't know, lots of replacement instructions in the manual indicates releasing tension on the torsion bars as a first step so I'm a little nervous something isn't right but it seems to be going together nicely. I should be able to have everything finished up this weekend and go get it aligned. I appreciate the insight and hopefully I haven't diluted the scenario with too many details.

So with the truck lifted on stands, I jacked up the lower control arms to get the correct z height and torqued down the upper and lower ball joints since they were easy to get to with everything off. Then I put the axles and tires back on and put the truck on the ground and my z height was off approx 2" (z=4" instead of 6"). Guessing because my tires are 2.2" taller than factory, this is why.? I should have mentioned the tires earlier. So I adjusted the torsion keys to get the height back to spec. Just wondering what torquing the ball joints at the incorrect height will do. May try to get at them and see if I can re-torque them. Guessing they actually need to be loosened but I can't picture it in my mind yet...

1993 GMC Yukon SLE 4wd... The manual says to make sure the z height is correct before torquing any ball joints or control arms as it relates to replacing. My truck z height wasn't right to start with and the torsion keys were adjusted for leveling after a body lift by the guy I bought it from. Angles were always pretty bad and the sway bar links always looked tweaked. All my suspension parts are removed (lower ca stayed but I loosened nuts) and I'm putting everything back but am confused and nervous on how to start at the correct z height... I put the torsion key where it is supposed to be from manual (34mm from bottom of retaining plate to top of bolt head) because when I tried jacking up the lower ca to get the z correct, it would lift the truck from the stands. Even with the torsion adjustment almost all the way out after setting it per the manual, it still takes a lot of force to get the lower control arms up to get the correct z but it's there. Just seems like a lot of tension and makes me nervous torquing everything down while it's like this and I just want to make sure I'm thinking right. Does this simulate the truck's load enough? Doesn't seem right to put the wheels on and put the truck on the ground and trying to get to the ball joints to torque them. I guess the upper and lower ca would be easy enough. Do I leave everything snug and put the truck on the ground, get the z correct, then torque or can I jack up the lower ca and get the z correct and torque everything like that? Thanks!