2004 - Trailblazer - Proper Alignment - Camber - Caster - Rear Diff

[webdawg]

<rant>
I don't know if just Firestone is horrid all over America or all franchise alignment shops are. I have been to alignment shops in about 4-5 states over the years and I have never had a good experience with any of them. I tried sears too and it was just as bad. The steering wheel is always crooked on any vehicle I take to any of these shops. I have had to take vehicles to shops a min of 3 times to get them to ever do it right, visiting different ones until I find a good tech. Sears I had to go to 2 different locations with the last location getting the manager involved, who understood, and actually fixed my vehicle. From an old honda, a brand new Ford Focus, a newish equinox, and then to the trailblazer now they can never seem to get it right.

I even had the dealer do it right once and they completely fucked it up. Washington State, Pennsylvania, Tennessee, Georgia, North Carolina, Alabama. They all suck. One time in Alabama I saw them lowering a car and they destroyed that one somehow crumpling a part of the body. What the hell is the deal?

</rant>

So the 2004 Trailblazer. The first tech to look at it started talking to me about how my rear wheels are loose and there is no way to align it. That when the car is jacked up you can pull them in and out. Is there supposed to be absolutely no play in the rear diff? (In and out) I was told that it was fine. I ended up taking it back and getting an alignment and they had to fix the camber. (I guess you have to use a pry bar?) They kept giving excuses like it was impossible. They ended up getting it right though.

The steering wheel was off but the alignment seemed to be right. I needed to drive it for a while. I just took it back last weekend to get the steering wheel strait and they (Firestone) tell me my caster is off and that they do not have the tool to adjust it, and that they are not even required to adjust it. They did say if I get the tool, that they would do it, or if I came back during the week they would do it because they could get the tool. I want to do it on the weekend so I was just going to buy the tool to have. Do they really need a tool to fix this? What gives?

Is this what they are talking about: http://www.amazon.com/OTC-7840-Caster-Camber-Adjusting/dp/B000O80B1G

or

Is this what they need?: http://shop.advanceautoparts.com/p/lisle-caster-camber-adjuster-for-gm-vehicles-lis32510/25961520-P

Will this work?

Now the car is not aligned and the steering wheel is still off but the other way.

 

[AtlWrk]

That's insane There's nothing mythical about these vehicles when it comes to an alignment. I have heard of shops saying that the camber cannot be adjusted on our vehicles because it doesn't "look" like it can be. This is completely untrue and the only special tool, if you can call it that, needed is a crow bar. There are tools that can make the job easier but are in no way required.

 

[The_Roadie]

In my decade on three forums, the honesty and general competence of any shop is set by the manager. Not by Franchise HQ. That said, Firestone gets FAR MORE bad reviews on Yelp and on the forums than other chain stores, but in general chain stores are at a lower level of competence than independents that live and die by word of mouth about their single location.

Customer's failure to research on Yelp is what keeps dishonest shops alive far after their natural progression should be to die.

Too many shops claim incorrectly that our platform has NO camber or caster adjustment, like we're some lame MacPherson strut design where that can be true. Camber and caster have to be set FIRST by moving the lower control arm. The position fore/aft of the lower ball joint sets caster. In/out sets camber. It's an iterative process to put the ball joint into a fixed location, then measure BOTH camber and caster and get them in spec, THEN tighten the three LCA mounting bolts. It's annoying, and can't be done in 30 seconds, and many techs either lie that it can't be done or they haven't read the manual SPECIFICALLY for our platform and know how it's done.

Once camber and caster are set, then they can do toe-in. Steering wheel centering has to be confirmed AFTER the toe-in is in spec, and if it's off, then the TRE adjustment has to be repeated until it satisfies the centering AND the tow-in specs. Again, an annoying iterative process that costs more than on a Honda, and if the shop expects to make maximum profit on EVERY customer, they're going to be disappointed when they align a GMT360/370.

Screw 'em. If they can't deliver an honest alignment for a fair price go elsewhere.

ONLY reason I'd ever go to a national chain is if I expected to use their warranty in another state. I use regional or local chains if I use chains at all. Les Schwab in the northwest, for instance, USED to be one of those. Not anymore, but they WERE good.

The second tool you linked to is one I carry around to loan the alignment shops. And I always have to explain the process to the tech. Shops who won't allow me to be near the tech during the process don't get my business. Insurance be damned - I'm not UNDER the lift. And a tech who won't take advice also triggers a discussion with the manager. I've taken my truck out of shops after it's on the alignment rack if the tech won't engage with me.

A pry bar is enough for any competent tech to shove the LCA around for experiments. The eccentric pin tool in the center bolt hole only helps hold the arm in place while they tighten the outer two bolts.

I ALWAYS have to explain the flipped UCAs. All offroaders do.

 

[Bow_Tied]

... Camber and caster have to be set FIRST by moving the lower control arm. The position fore/aft of the lower ball joint sets caster. In/out sets camber. It's an iterative process to put the ball joint into a fixed location, then measure BOTH camber and caster and get them in spec, THEN tighten the three LCA mounting bolts. It's annoying, and can't be done in 30 seconds, and many techs either lie that it can't be done or they haven't read the manual SPECIFICALLY for our platform and know how it's done.

Once camber and caster are set, then they can do toe-in. Steering wheel centering has to be confirmed AFTER the toe-in is in spec, and if it's off, then the TRE adjustment has to be repeated until it satisfies the centering AND the tow-in specs. Again, an annoying iterative process that costs more than on a Honda, and if the shop expects to make maximum profit on EVERY customer, they're going to be disappointed when they align a GMT360/370. ...

Thanks for the informative post. I think I need to help my shop get up to speed on this issue with GMT360s. I need to dial in my caster/camber and they have suggest they can only do this with some special GM only eccentric bolt kit that take up to 2 weeks to get. So I don't think they understand what the procedure is (unless an '06 Denali is some how different???). Although I have read your response a couple of times, and I get the jist of it, I don't have it down well enough to point and say "Do something with that bolt" kind of thing.

I have a manual downloaded I think from this site (several PDF files) but I cannot find the procedure, perhaps I messed downloading the correct section. I can also not find any useful pictures on the net. Can anyone direct me to some manual data or a step by step procedure with pictures? I would like to show the shop something professional looking. I have personal experience with this shop being honest and helpful for me so I am overlooking that they don't know this procedure.

Thanks!

 

[Tiggerr]

I hate to even utter this phrase..lol..but a dealer is usually been the best place I've found for an alignment. They know the vehicles and have all the latest do-dads and highest dollar racks out there, and usually (I said usually) have better trained techs than any tire shop.

 

[Bow_Tied]

That may be true in some cases. The shop I am dealing with is a smaller, private run shop. I have built some relationship with the people there and feel that they try to do their best for me. I have had my truck in there several times where the answer was "no charge" for example. So, yes, educating them shouldn't need to be a part of my requirements as a customer, however, I think it has to be tough to be an expert in any random vehicle that shows up at the door on any given day. Is this issue one they ought to have known? Perhaps.

The other challenge is that I have already paid for an alignment so if I go anywhere else I have to pay again.


Further digging, the Lisle tool appears to be discontinued.

 

[The_Roadie]

Any shop should be have access to a DVD or on-line manual set, but here's the summary.

The Lower Control Arm bracket is item #13. It's held in by three hardened bolts with the highest torque spec in the vehicle - 185 ft-lbs, I think. Loosen these three.They are item #40, but only one is showed.

On the LCA bracket there are two oval protrusions in the casting, and these show through oval holes in the frame mount.

With a loose LCA mount, the lower ball joint can be moved around to adjust camber and caster. In and out adjusts camber. Fore and aft adjusts caster. You move the LCA mount either with the special eccentric pin tool, OR VERY SIMPLY using a pry bar or big screwdriver around the openings that reveal the oval part of the LCA bracket. Once the three bolts are loosened a bit, it's EASY for the tech to see how the bracket moves.

The challenge is that a loose LCA bracket allows the lower ball joint to move anywhere - in/out and fore/aft, and the camber and caster change at the same time. It's a possibly frustrating challenge to find a location that gets both the camber and caster in spec at the same time, but it's an interative process. Move, check, lather, rinse, repeat.

The lower ball joint movement will ALSO change the toe-in, so the camber and caster have to be brought in spec first and the three bolts tightened, THEN as a final step in the process, the tech has to adjust toe-in and steering wheel centering.

 

[Sparky]

This is why I very well may drive all the way to the north side of Columbus again to get any alignments as there is a shop there that is excellent. The tech there spent a solid hour doing the alignment. Adjusted, drove it, tweaked it, drove it a second time, and verified. How many places do that? Not many in my experience. My lift didn't faze them at all. A bunch of the guys came over to look at it as they hadn't seen a lifted Trailblazer before, and commented on how brilliant it was to flip the control arms (told them I couldn't take credit for that one!).

That is probably the only thing I miss about living down there. I lived no more than a mile down the road from there.

 

[Mooseman]

I've rarely had good luck with independent shops for alignments. Even a "simple" vehicle, like my son's Honda, we couldn't get a good alignment but then took it to a GM dealer (he used to work there) and it was the best alignment we ever got. And it was priced the same as other shops. I plan on taking my Saab there soon.

 

[Bow_Tied]

Roadie, thanks so much. That is exactly what I needed. I truly appreciate the time you took to post that.

IMHO, this thread is worthy of a sticky thread status or whatever you call it when they stay visible at the top of a forum.

 

[DocBrown]

I think there are very few truly good alighment shops left. We had one where I live then one of the owners decided to skim off the top of his own buisness. Needless to say they went out of buisness. There really isn't anyone where I live that I even trust anymore for front end work.

 

[Bow_Tied]

Follow-up:

This is the conversation with my shop after I emailed them Roadies explanation and diagram:

Shop:
That is way more work than replacing the 2 bolts (#3) [with the eccentric adjusting bolts]
You just rotate them.
Not even mentioned in any of the tech manuals for alignments..

Me:
[SIZE=11pt]Agreed, it is a more iterative process. The flip side with the eccentric bolts is that I could be into replacing control arm bushings or possibly the control arm itself if things are really seized together, correct? [/SIZE]

[SIZE=11pt]Shop:[/SIZE]
[SIZE=11pt]Yeah[/SIZE]


This was the conversation with the service manager. Their actual tech was out for the day. I am going to chat with the tech next week. If I don't get a warm and fuzzy feeling then I guess I am headed to the dealer.

 

[Sparky]

Some places are just dense and/or lazy

 

[blautens]

This is the conversation with my shop after I emailed them Roadies explanation and diagram:

Shop:
That is way more work than replacing the 2 bolts (#3) [with the eccentric adjusting bolts]
You just rotate them.
Not even mentioned in any of the tech manuals for alignments..

Me:
[SIZE=11pt]Agreed, it is a more iterative process. The flip side with the eccentric bolts is that I could be into replacing control arm bushings or possibly the control arm itself if things are really seized together, correct? [/SIZE]

Don't go back. Why is he arguing? How f--king hard is it to loosen three bolts and move the arms by the brackets? I take my cheap HF pick/pry bar set to move the arms around.

Every alignment but one on this truck that I had someone else do was not good. Sometimes laughably bad, were it not mine.

Still, it's not rocket science - and Roadie explained it perfectly - and actually his clear explanations over the years are really why I stopped letting mouth breathing "technicians" (who watched a Hunter video) align my truck.

When I started looking into alignment and realizing that if the guy next door racing his 935 in vintage SCCA is using strings to adjust toe and essentially a digital level mounted in a 3 spoke aluminum holder to do caster and camber alignments, a little money (and it can be very little) and a few hours of my time learning how to do this was going to be less money than I pay in therapy complaining about this.

Here's the thing - loose control arms could possibly be a problem in these trucks after an alignment - you can get things all lined up and then 5 miles down the road things shift (yes, that happened to me, thanks Tires Plus) - you have to tighten those bolts down pretty well, especially the front one which kind of gets hard to turn but then easier and still has a way to go (at least on mine) - but you can see it pinching in the material if you actually look at it (which I'm sure they are not). The specs:

Lower Control Arm Bracket Front Mounting Bolt 265 N.m - 195 lb ft
Lower Control Arm Bracket Rear Mounting Bolt 240 N.m - 177 lb ft
Lower Control Arm to the Lower Control Arm Bracket Mounting Nuts 130 N.m - 96 lb ft

Also my rear bolts were in rough shape - the slightly rusty surface underneath the bolthead was probably good in the sense that it added friction and kept the bolts from turning easily, but enough material had rotted away on the bolt itself near the head just before the threads that after I cleaned them up I didn't feel I could safely torque them down, so I got new ones.

And if your control arm bushings are shot, the chances are the tie rods and ball joints could be pretty wiggly, too (if you haven't replaced them), so it's time to do some exploratory surgery.

(And again, all credit to Roadie, who in 30 minutes can probably replace inner and outer tie rods on the side of the road with locking pliers and one arm tied behind his back and eyeball the alignment, whilst I need 2 days, a bunch of beer, a load of tools and my quiet, safe, level garage, sans kids and dogs.)

 

[Bow_Tied]

Classic reply! Loved the therapy comment.

I have the front end inspected a couple of times and everything is tight. At just over 60k miles in the rust belt you never know what you'll find but I figured if I could avoid messing with control arm bushings, assuming they passed visual and were tight then I would and should.

I didn't get an arguement. Actually agreement to try. I'm also trying to see things from their point if view that many customers complain about symptoms and try to get shortcuts to save money or worse try to tell the shop how to do their job when they have no clue themselves. It's natural to be suspicious of a non mechanic customer. I don't tell them I'm in mechanical engineering. That seems to make it worse lol.

 

[blautens]

I have the front end inspected a couple of times and everything is tight. At just over 60k miles in the rust belt you never know what you'll find but I figured if I could avoid messing with control arm bushings, assuming they passed visual and were tight then I would and should.

Do you have actual vehicle inspections? Where they actually....inspect? I live in Florida, so I'm always hoping the lack of inspections here will help "thin the herd". Sadly, it's not thinning fast enough.

Actually, though, I was a police officer the last time we had inspections in the 90's (and it was just emissions then), and all it did was increase the number of stolen license plates.

 

[Bow_Tied]

Yes. We have safety inspections but only at time of ownership transfer. Roadside random checks happen but are very rare.
Plus there are emissions check ever 2 years (5 year exemption for new vehicles). But the emissions check is just CEL ready status verification. Mainly a tax grab (liberal govt).

 

[Bow_Tied]

Had a good chat with my shop today. They understand what I am asking for. They'd be willing to do it but they can't - their alignment rack, which appears to be in otherwise good shape, does not have have the bottle jacks in-board of the front tires (they've never really used them and so deleted them at some point). Therefore they seem to think they couldn't perform LCA bracket method alignment work and are suggesting an alternate shop if that is the method I must have.

Question, does this make sense? If you took the weight off the front tires the alignment would change would it not? I realized from the initial description from Roadie that it was an iterative process, but if one has to lift the vehicle slightly to take the weight off to adjust the lower bracket I could see that this would be a very, very iterative process as the suspension may not settle fully between adjustments. So, is the intent for this to be done with full weight on the vehicle?

My shop took time to show me the alignment rack, the Moog instruction manual that shows the eccentric bolts for the UCA. They even checked that the UCA bolts are freely rotating so as to avoid risk to the UCA bushing replacement. I think what I would really like to find, if it exists, is a link or hard-copy of an original / official alignment instructions that shows this method of LCA bracket adjustment. Without that I am just some jerk saying, "...well, the internet told me so." to which every shop owner everywhere secretly rolls their eyes when they hear this. Having worked in similar situations, I can understand that there a lot of know-it-alls out there.

NOW - I know what many of you are thinking here, "Just go somewhere else for goodness sake". I can see this view point and even agree; however, without this instruction manual type data in hand I fear I will start the same conversations all over again back at square one at any other shop.

Does anyone have a link to official alignment instructions method, a pdf, or something I can print off?

PS - if I take my Voy to a GM dealer, should I have a high confidence that they use the LCA bracket alignment method?

Thanks for reading and many thanks for your valued input.

 

[Sparky]

I don't see how eccentric bolts on the UCA would even do anything seeing as there is just a bolt hole without anything for it to adjust. Nothing moves in or out up there. An eccentric bolt would just look funny but do the exact same thing the regular bolt does, unless they were to modify your upper suspension (and they had better not!). Only the lower arm bracket has the slots in it for movement.

The shop I went to had sliding "pads" that the front tires would sit on. The jacks would take off the weight so things wouldn't slide around when they were making adjustments, but the sliding pad would allow the suspension to easily settle. I think sometimes they could tweak things carefully with vehicle weight still on it, not sure.

Sorry I don't have anything official. I just do not understand how a shop can't look at the two arms and see what moves. It is staring them right in the face for pete's sake.

 

[Bow_Tied]

The shop claimed to understand what I was asking for. But have never done it this way, so they are naturally gravitating to what they know. Most of the trail/voys they have done have not required camber/caster adjustment and the odd one that has the eccentric bolts did the trick.

The eccentric bolts are a bolt with a built-in cam. After the bolt is installed rotating it creates an offset between the mounting hole on the truck and the mounting hole on the UCA. I think he said there are two bolts (item #3 in the diagram Roadie posted above). You install eccentrics in both. If you rotate them the same it adjusts camber, opposite it adjusts caster. They said this sort of eccentric bolt deal is common for many vehicles.


EDIT
In my continuing search, I found this, but it looks sketchy and so does the torque spec:

I found this here: http://www.tbssowners.com/forums/how-do-write-up-section/5204-how-do-quick-alignment-tbss.html. I can't tell is someone made a Word document and someone else photocopied it or if it is from a manual or what.

 

[Tiggerr]

Some vehicles do use those types of eccentric bolts. Our platform does not. They do not know what they are talking about. They do not know this platform, or have a clue what they're looking at under there. I wouldn't let them align a unicycle!

As in that pic you posted above, the caster/camber is done from the LCA brackets. No other way to do it

 

[Bow_Tied]

The more I read, the more I agree.

I just can't prove it, yet.

 

[Tiggerr]

Got to be a better shop or dealer somewhere near you

 

[coolasice]

Service Information
Home Publications Number Search Bulletin Search Help

2005 Chevrolet TrailBlazer - 4WD | Envoy, Rainier, TrailBlazer, Ascender (VIN S/T) Service Manual | Suspension | Wheel Alignment | Repair Instructions | Document ID: 742681
Front Caster and Camber Adjustment

The caster and camber adjustments are made by loosening the lower control arm adjustment bolts and repositioning the lower control arm.

Important: Before adjusting the caster and camber angles, jounce the front bumper 3 times to allow the vehicle to return to normal height.
Measure and adjust the caster and the camber with the vehicle at curb height. The front suspension Z dimension and the rear suspension D dimension are indicated in Trim Heights. Refer to Trim Height Inspection .

For an accurate reading, do not push or pull on the tires during the alignment process.

Object Number: 365807 Size: SH
Click here for detailed picture of above image.
Determine the caster (2, 3) angle.

Object Number: 365809 Size: SH
Click here for detailed picture of above image.
Determine the camber (2, 3) angle.

Notice: Refer to Fastener Notice in the Preface section.

Object Number: 742660 Size: SH
Click here for detailed picture of above image.
Loosen the lower control arm adjustment bolts (1).
Adjust the caster and the camber angle by repositioning the lower control arm (2) until the specifications have been met.

When the adjustments are complete, hold the lower control arm in position so that the specifications do not change while tightening the lower control arm adjustment bolts.

Tighten
Tighten the front lower control arm bracket mounting bolts to 265 N·m (195 lb ft).
Tighten the rear lower control arm bracket mounting bolts to 240 N·m (177 lb ft).
Verify that the caster and the camber are still within specifications. Refer to Wheel Alignment Specifications .
When the caster and camber are within specifications, adjust the toe. Refer to Front Toe Adjustment .

© 2015 General Motors Corporation. All rights reserved.

 

[Bow_Tied]

Got to be a better shop or dealer somewhere near you

Is going to a dealer a good likelihood of getting this procedure?


Coolasice - awesome info, thsnks! Is there a hyperlink to the source you can share?

 

[coolasice]

ill try to upload screens in a few

 

[Blckshdw]

I managed to print these off, same info CoolasIce had

 

[coolasice]

ha... beat me to it... here is the camber/caster in pdf format...

 

[Sparky]

The shop claimed to understand what I was asking for. But have never done it this way, so they are naturally gravitating to what they know. Most of the trail/voys they have done have not required camber/caster adjustment and the odd one that has the eccentric bolts did the trick.

The eccentric bolts are a bolt with a built-in cam. After the bolt is installed rotating it creates an offset between the mounting hole on the truck and the mounting hole on the UCA. I think he said there are two bolts (item #3 in the diagram Roadie posted above). You install eccentrics in both. If you rotate them the same it adjusts camber, opposite it adjusts caster. They said this sort of eccentric bolt deal is common for many vehicles.


EDIT
In my continuing search, I found this, but it looks sketchy and so does the torque spec:

I found this here: http://www.tbssowners.com/forums/how-do-write-up-section/5204-how-do-quick-alignment-tbss.html. I can't tell is someone made a Word document and someone else photocopied it or if it is from a manual or what.

That does not work. This requires two things - a slotted bracket where the bolt goes through and tabs for the bolt to hold against. Neither exist on our upper control arm. It is a simple straight hole through the arm and into the upper tower. It would take modifying the upper mounting points a fair bit to use those bolts.

Go to a different shop.

A GM dealer should have no problem (in theory) since they have all the official service manuals.

 

[Bow_Tied]

Folks, I can't say enough how grateful I am for the data and the support. This site proved itself once again, thank you all!

I have decided to move on to a dealer. It'll cost me an alignment fee once again; however, I think it is worth it.

One last procedural question for my own curiosity: to make the adjustments to the LCA bracket is the vehicle weight supported during that procedure or is it done with full weight on the wheels?

 

[Tiggerr]

Don't think I've seen anyone align with vehicle off its suspension. I'd say on it. That's why those little pads the tires sit on move.

 

[Bow_Tied]

Thanks. That makes sense. The manual/instructions don't comment on this so i thought I'd double check.

 

[coolasice]

Says to adjust at curb height...

 

[Bow_Tied]

Missed that. Perfect, that seems logical.

 

[blautens]

Says to adjust at curb height...

Which is not fun when you're 6'5" and 250 lbs trying to crawl under the TBSS. Oh, to have a lift, or even 4 of those cool raised stands I see some weekend racers with (who granted, have 2500 lb Mazdas or Subarus).

I know I shouldn't whine - it has more room than many cars, but I get spoiled even just having it on jackstands for so many things but then having to drop it to do the final torque on bushings and push the control arms around. Stupid 20 inch tires really take up a bit of room, too.

Missed that. Perfect, that seems logical.

I PM'd you a link or two for your reading pleasure.

 

[Bow_Tied]

Which is not fun when you're 6'5" and 250 lbs trying to crawl under the TBSS. Oh, to have a lift, or even 4 of those cool raised stands I see some weekend racers with (who granted, have 2500 lb Mazdas or Subarus).

I know I shouldn't whine - it has more room than many cars, but I get spoiled even just having it on jackstands for so many things but then having to drop it to do the final torque on bushings and push the control arms around. Stupid 20 inch tires really take up a bit of room, too.

I'm only 6'1", 210. So I can relate to a lesser degree. However I just recently got a 4 post hoist so I'm really pumped. I'll have to ditch my garage door opener and even then I'll only have 10'5" but still it should help. Not getting any younger.

I PM'd you a link or two for your reading pleasure.

Many thanks, pm reply sent.

 

[webdawg]

I guess I forgot to subscribe to this thread. Fixed. Thanks for all the great information. I did end up getting their act together for them. I had to go do a few different shops but in the end they got it right. In the future I have everything I need now.

 

[Bow_Tied]

I wanted to do a little follow up on my alignment issues.

The original shop had the alignment close, not quite right, the steering wheel just a tad off, something else just a hair out of spec. Drove ok, but kinda bugged me. My wife drives it daily and she was ok with it so for a while I did nothing. Not long after that there was clunking issue in the front end and I took it back to the same shop - it was an inner tie rod on the new (rebuilt) steering rack they had installed at time of the original alignment issue. That was a warranty repair. I was expecting another round of alignment conversation but the alignment sheet came out perfectly in spec. I quizzed the service manager who, this time, was speaking more freely as he was leaving this place for a different job. The shop had the previous month put in a new $25k alignment rack. The owner had been trying to limp along with a very dated rack (the computer head was new) until he could afford a new one. It worked well enough for many vehicles but as more and more newer vehicles came in I guess it was a slowly mounting problem. The design of the rack didn't lend very well with the LCA adjustment method, tight access or something. I would rather have been told that up front but I can understand where the shop owner would not want to advertise his shop equipment was inadequate.
Anyway, all's well that ends well I guess. Same shop just replaced my steering rack under warranty.