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Old 02-21-2019, 02:03 AM   #11
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Those steps are pretty accurate, although the rolling part has mostly gone away if they are on good turntables that float easily. Toe is the biggest one for that issue. The problems really start if they have jack up a wheel or two to get to the adjusters and then drop it down again. Even bouncing them doesn't always settle the same, especially for stuff sprung as stiff as our vans. Rolling and bouncing is always better, it is just a matter of how much.
Do you have a turntable or equivalent with your homemade setup?
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Old 02-21-2019, 02:11 AM   #12
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Do you have a turntable or equivalent with your homemade setup?

I just got a set of turntables (second set first was junk) and played with them a little after I modded them for more travel. They will make it much easier once I get out on the level driveway in the spring. I did try the two vinyl floor tiles with grease between them, and it worked suprisingly well, so that is also an inexpensive option for folks. With the tiles, I would definitely roll the vehicle when doing toe, and probably camber. Caster not as critical I think.
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Old 02-21-2019, 03:03 PM   #13
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What if the bolts on the inside of the cam adjuster were slotted or something preventing them to rotate as you loosen the accessible nut ?
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Old 02-21-2019, 03:47 PM   #14
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What if the bolts on the inside of the cam adjuster were slotted or something preventing them to rotate as you loosen the accessible nut ?

The bolts go through slots in the frame, so the A arm can move in and out, so you would need to have some kind of floating nut plate to allow the motion in and out, but prevent turning. Probably could be done, but GM would never put that much cost into them. The previous generation didn't even come with cams, so you had to buy them to be able set the camber and caster. I am pretty sure the bolts and nuts are high strength hardened material so it would be pretty costly compared to off the shelf nuts.
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Old 02-21-2019, 03:56 PM   #15
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The previous generation didn't even come with cams, so you had to buy them to be able set the camber and caster.
I saw the cams for sale and bought a set. But it looks like my 2006 has something that looks similar. Sounds like I didn't need to buy the cams.
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Old 02-22-2019, 06:14 PM   #16
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Wow, the last two posts certainly confirm what I was very suspicious of, and that is huge repeatability issues with the machines. Even though they read to .01 increment, they are really closer to .2 repeatability, which is no better than the bubble gauges are for accuracy, but they seem to repeat better than the machine does.

It is no wonder they don't want to move the cams, as they have no idea if the cam moved the reading or it just changed because of the machine issues.

For camber, accuracy counts because you are talking very small numbers around zero and you need to get repeatable results to dial that in. I can't believe how many times they sent them out with plus camber on one side and minus on the other, which they also did to me and refused to change.

The actual caster numbers if high enough aren't all that critical, but having the cross caster right certainly is so repeatability also important there.

The toe numbers also seem to be a random thing, likely because they do it last and probably cheat and don't rescan before printing it out.

It appears lejeep has paid for two complete alignments and the only thing they set was the toe, and they messed that up. He has noted that the cams on his have not been touched.
Looking again at the after and before new adjustments numbers from me and D&J Phillips. it seems that caster is the least affected by the non repeatability thing. Then would come camber and the most non repeatable numbers would be toe.
I wonder if bearings (caster) and steering linkage (toe) could be contributing factors for numbers non repeatability.
Did you notice the same pattern on your van or was it random ?
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Old 02-22-2019, 06:23 PM   #17
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Looking again at the after and before new adjustments numbers from me and D&J Phillips. it seems that caster is the least affected by the non repeatability thing. Then would come camber and the most non repeatable numbers would be toe.
I wonder if bearings (caster) and steering linkage (toe) could be contributing factors for numbers non repeatability.
Did you notice the same pattern on your van or was it random ?

If they are calculating the caster the same way as it is done with the manual gauges, that does kind of make sense, as the caster is the taken from two readings that kind of balance the errors out, it appears. I have seen that with the bubbles also in my messing around. The bubbles have been much more repeatable than the readings you guys have put up off the machines, though, probably because a very small wheel movement would probably really mess up the machine but with the manual gauge you rezero the gauge in the tire rotation direction. With as much unrepeatability as they are getting, they would time and accuracy ahead if they just used and old pointer gauge, I think.
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Old 02-22-2019, 09:32 PM   #18
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Booster, I wrote that wrong. I meant to ask if some front bearing looseness would affect camber (not caster) results non-repeatability and steering linkage looseness would contribute (even more) to toe results non-repeatability.
I noticed that D&J Phillips and I have about the same mileage and maybe same wear on those parts.
D&J Phillips, did you have any of those parts replaced to your knowledge ?
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Old 02-22-2019, 10:14 PM   #19
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Front wheel bearing looseness certainly could show up as variability because it would make a difference which was the looseness was pushed out. I think with aluminum wheels that have the big negative offset, the centerline of the tire would be near being outside of the area between the wheel bearings, do those would go negative camber almost all the time. If the center of the tire is between the bearings like it should be the tilt would be more centered and could be pushed either way a bit. Ball joints, particularly lowers, are a normal cause of camber movement, but the rest of the steering parts won't change camber except for pushing when turned and moving a loose balljoint or bearing.


Age of front end parts, and even mileage are not good indicators of if they will be worn, as ungreased ones can be shot in under 20K miles and well maintained ones can go well over 100K.
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Old 02-23-2019, 05:08 PM   #20
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@lejeep - when I bought it in 2014 it had just over 40k on it. First thing I did was go to the dealer to have ALL fluids changed, then to the tire/suspension shop with instructions to replace anything they thought needed replacing and they replaced the ball joints, 2 or 3 tie rod ends, and the rear 'brace' bushings (Dodge has a lower "A" arm that is not actually an "A" arm but rather sort of an "I" arm with a separate rearward brace from the lower ball joint area to the frame). The result is that anything that moves was replaced/checked. I then had the steering box rebuilt by Red Head and added this steering box stabilizer Dodge Ram Steering Gear Box Stabilizer. Also got a new set of shocks and the tires are relatively new.

So, that is when I went back for this series of alignments. The only upgrade I didn't make was the addition of a rear sway bar, which I think would help but it is very crowded under there and I am not sure I can get one in along with the air bags.

@booster - on the need to roll after setting it down after an adjustment. I have no experience with heavy trucks like our vans, but I have set and maintained my Austin Healey for racing for 20 years and I think rolling between settings is necessary for camber as well as toe. Healey's left the factory with no adjustments possible except toe. There are now replacement suspension mountings that can be welded in to allow adjustment but most of us just use eccentric bushings - and, since there are no factory adjustments, the alignment shops don't want my business...they are all afraid of liability if they make a setting outside 'factory' parameters. This means a lot of trial and error. I use plumb bobs and chalk on the shop floor, roll the car out of the way and measure, roll back and make another stab, repeat. In this process I have found that there is enough arc difference between the lower A arm swing (long) vs the upper shock (a arm) swing (short) that the side movements of the wheel are going to put the tire and suspension in a bind until you roll the car. Having said all that, I have not tried skid plates of any kind so maybe they work better than I imagine.

I still think most of the problem is operator error/laziness. The general feeling is that the computer can't lie, therefore it speaks the truth. In my case the frustration was compounded by the fact that the technician seemed sharp and genuinely desirous of giving a good result and worked with me cheerfully - I just couldn't shake the feeling that he really didn't get why I was being so demanding? Also, I have no idea how comprehensive the training is for and alignment tech? When I asked him to do it again, he cheerfully complied, but never decided on his own to redo any particular result. A couple of times I even booked two alignments back to back so he could take as much time as needed and wouldn't feel rushed - and kept offering to pay more if 'machine time' was an issue.

All this is why I generally do things myself - it is often easier than trying to educate someone who thinks they already know. It's not that I think I am a superior mechanic, but rather that I am driven by a fundamental issue......WHY? The need to understand what is going on is paramount.

Dave
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