I replaced the Right Upper Control Arm on my truck. I read that I shouldn't tighten the mounting bolts for it till the truck is back on it's wheels since I didn't mark the position of them before removing the old arm.
My question is how loose should I leave them till then?

I also replaced the steering knuckle & read the same about tightening the axle nut.
So again, how loose should I leave it?

 

NO.. The control arm bolts should be tightened before you install the tire/ wheel... But it is a good idea to put the jack under the lower A frame and not the truck frame so the truck is setting in the "run" position and the A frame is not pointed downward.

NO on the axle also. The center nut must be around 200 ft pounds torque PRIOR to setting on the ground. It puts the crush on the two bearings. If you set the tire on the ground you will **** the bearings and they may not seat correctly or scrape trying to seat themselves.

 

You will need some type of alignments on the upper control arm to verify caster and camber and toe in. If you want to do it yourself (??) , after the truck is setting on the ground, check the ground between the front tires to verify you are LEVEL side to side and not just FLAT.. If the truck is LEVEL then use a 2 ft level and put vertical on the outside of the tire and see that it is tipped in about 1/4 - 3/8 inch at the top. Don't put the level on the bumps or white letters on the tire... set on the flat sidewall. If the tire tips in or out too much, then you need to remove the tire, loosen the bolts on the upper control arm and push in or out ( depending on the level) to get correct. Note that you can not adjust caster and camber as you can not measure the fore-aft only the tip in-out of the tire. Also note that the tire is 30 inches tall and the A frames are about half of that apart, so if you want to tip the tire in 1/2 inch, you loosen the control arm bolts and push the frame inward HALF of that or 1/4 inch.

I have also measured the toe in by putting a concrete block next to the front tire outside on each. Set a 2 x 4 about 3 ft long on top of each. With your buddy, push the 2 x 4 up against each tire and use a 8 ft ruler to measure outside to outside the 2 x 4 s in front and behind the tire.......... the reading in the front should be maybe 1/8 inch less than the back........ that is TOE IN... adjust one of the tie rod ends to get that. Keep steering wheel pointed dead forward to determine which rod end to adjust.

 

Negative & Positive Camber, Caster Angle, and Toe Angle

 

Thank you, Steve for taking the time to write all that.
Thankfully I didn't get to that step yet.

 

since you have no idea where the original arm was bolt ( alignment), it would be best to take it to a shop. You might do an initial check of camber and toe it to make sure your not scuffing tires... I mark the original position of the control arm prior to removal, then use the above method to fine tune ......... no shop needed.

 

Since I'll be going to get it aligned as soon as I'm done working on it, I just need it drivable to get there. So, I'm thinking that leaving them loose till it's on its wheels will be good enough.
When I went to tighten the control arm with it jacked up today, I was kinda surprised that I could move it thru its full amount of adjustment. I was expecting it to be in one spot.
I found it very interesting how much the geometry changed while sliding the arm around.

I don't see how I could keep the hub from spinning while torqueing the axle nut to 188-254 Lb/Ft so I'll be doing that when its back on its wheels also.

 

Well...that didn't work. Not sure what I'm going to do now.

 

You cant leave the bolts loose and set the truck on the ground. Jack it back up, take off the tire, loosen the bolts a turn or two......... smack it with a hammer or pry bar to get the top arm back in the middle of the groove somewhere......... then TIGHTEN the two bolts on the upper arm. It will not be in alignment, but it should stay in one spot....... as I mentioned above, you will need an alignment... if the tire appears to be TOO FAR OFF to drive to the shop ( check with level on outside of tire or just LOOK). then jack it up, take tire off, loosen the two bolts and push the arm in or out to get closer to a vertical position........... that will work till you get to the shop...... and don't drive with the spindle nut loose. You can TORQUE on the ground, but nut needs to be tight ( snug) before you set the tire on the ground.

 

I noticed that each end of the arm can be moved independently of the other. Meaning the front part of it can be slid outward at the same time the back part is slid inwards & vice-versa. And of course they can be slid in & out together. That leaves me wondering which way should I adjust them. And do they need to be positioned the same? Such as both 2 notches inward.

 

Move them in and out together changes the camber.


Moving one in and t other out changes the caster.

 

As I mentioned above, you cant verify the caster at home with a level and ruler. You should move the arm equally in or out and tighten the bolts, then check the tire on level ground to tip in slightly at the top (camber) ...... That's the best you can do at this time. If you want to check the toe- in to make sure it don't plow down the road, that is a good idea. You can visually look at it and make sure its "CLOSE" if your only driving several miles to the align shop.

 

Ok. Many thanks guys!

A friend came over & we did some of the things mentioned. He also adjusted the right outer tie rod. It pulls to the left but not as much as it was. I have an appointment for an alignment tomorrow which I should be able to drive it to.

Thanks again!

 

 

Well...got the alignment done...they made some adjustments but still pulled alot to the left...went back...they rotated just the frt tires...now pulls to the right alot but not quite as bad as it was to the left...they said it was due to radial pull...what the heck is that?