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Discussion Starter #1
2003 Envoy - Steering wheel changed position after a hard braking. I measured the center to center distance between the front tires at the leading and trailing edge and the difference was 4-1/2"! I removed the front tires and everything in the front suspension is tight. There is no play in the outer tie rod ends, ball joints, control arm bushings, etc. With the steering wheel centered, the excessive toe in can be seen at both wheels. I had a helper hold the steering wheel while I put a 24" pipe wrench on the knuckle and attempted to move it to see what was loose and could not get anything to budge.

I put the tires back on and backed up at 20-25 MPH and slammed on the brakes and the toe corrected itself - the steering wheel was not centered but there was no longer 4-1/2" of toe-in.

I'm thinking it might be something with the inner tie rods but am confused as to why I cannot replicate the problem by prying on the various steering and suspension components. Any ideas what to look for?
 

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Wow! Great description of your problem. Let's start simple first.....
  1. GENTLY... with one tire off and the other still on dry clean pavement... try to pry the tireless spindle right and left.
  2. Have observer watch for untoward motion.... any motion, really.
  3. Move first in one direction and check for a baseline value.
  4. Move spindle in opposite direction, re-measure toe again. .
Report back, please.

My money's on a failure in the rack or the inner ends and I haven't been wrong today.
 

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Discussion Starter #3
Wow! Great description of your problem. Let's start simple first.....
  1. GENTLY... with one tire off and the other still on dry clean pavement... try to pry the tireless spindle right and left.
  2. Have observer watch for untoward motion.... any motion, really.
  3. Move first in one direction and check for a baseline value.
  4. Move spindle in opposite direction, re-measure toe again. .
Report back, please.

My money's on a failure in the rack or the inner ends and I haven't been wrong today.
I checked each side both with one front tire on the garage floor and with both in the air. I had my daughter hold the steering wheel in a fixed position and with the front end on jack stands and attempted to rock each wheel tire (3:00 and 9:00) and it was tight - no relative movement in the steering linkage. I repeated the check on the other side and everything was tight.

Sunday afternoon, I marked some chalk lines on a stretch of road to outline the field of view of my cell phone camera and had my daughter take a video. I timed my braking so the max breaking force was when I was between the lines and there was an audible pop but the cell phone camera was not fast enough to see anything in detail. I believe the noise was from the right front. It also popped when turning into a parking space yesterday.

My thought was inner tie rods but the odds of both going bad at the same time seems unlikely and I am at a loss why I can't get it to pop by exerting force on the knuckle. If the rack was bad - as if it were jumping a tooth, it wouldn't affect the toe alignment - just the steering wheel position. The only other wear item that would cause the issue is the inner tie rods but the odds of both being shot at the same time seems unlikely.

I am wondering if there is a control arm bushing that is popping or shifting that is causing the issue even though I cannot duplicate it by prying on the various suspension parts with a prybar. I think a way to isolate it is to mark all the parts with a paint pen when it is not toed in and then get it to pop and inspect the marks to see what has moved.
 

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My next wad of if money is on a control arm bushing. If I'm not careful I could lose a lot of money here. Let it ride!

Of all the possibly semi-dangerous items to fail, a control arm bushing is low on the dangerous list. It will eat tires rather quickly though.

Dangerous things... that can cause death and destruction? Hmmmm... broken interlink in steering column....these are pretty bulletproof but could send you pintballing down the road.

Upper or lower control arms falling off? Not likely.
Ballpoint failures? Yeah.... not a good thing at speed.
Hub failure? You'll get more than adequate warnings.
Cracked/broken frame? Not likely, but could be devastating at speed.

How are the front tires wearing? Any feathering? Bald on one side?
 

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Discussion Starter #5
My next wad of if money is on a control arm bushing. If I'm not careful I could lose a lot of money here. Let it ride!

Of all the possibly semi-dangerous items to fail, a control arm bushing is low on the dangerous list. It will eat tires rather quickly though.

Dangerous things... that can cause death and destruction? Hmmmm... broken interlink in steering column....these are pretty bulletproof but could send you pintballing down the road.

Upper or lower control arms falling off? Not likely.
Ballpoint failures? Yeah.... not a good thing at speed.
Hub failure? You'll get more than adequate warnings.
Cracked/broken frame? Not likely, but could be devastating at speed.

How are the front tires wearing? Any feathering? Bald on one side?
I replaced the lower ball joints when I replaced the oil pan about 10,000 miles ago. They are still tight so I don't think they would be the cause. The hub bearing on the right front was replaced 4500 miles ago and the left front hub is quiet - no unusual noise.

I did not see any frame damage where the control arms attach. Tires seem to be wearing OK - there are no bald edges. Some slight "fish scaling" probably due to the toe being off but not bad. I'll rotate the tires once I fix the issue.

I'm thinking if there was something damaged in the steering column, it wouldn't affect the toe alignment - both front tires would still be in alignment but the steering wheel would be loose or there would be a dead band in the steering.

I am leaning toward a control arm bushing(s) but am confused as to why I can't replicate the issue by prying the control arms cross-car and fore/aft. It makes no sense.
 

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If you are allowing the suspension to hang when you Jack it up, the pressure of the spring will pull everything tight.

If you try to find any slop in the system that way, you'd have to be stronger than the coil spring. Not likely.

Jack the vehicle up and put jackstands out as far out under each of the lower control arms... right under the lower ball joints THEN try to find whatever is messed up.
 

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Discussion Starter #7
Update: My daughter got home from class this evening and said it was acting funny - sure enough, the front tires were "pigeon toed". I pulled it in the garage, removed the front tires and supported the front end on jack stands under the control arms as close to the lower ball joints as I could.

No play at all in the steering system - that ruled out the tie rod ends, inner tie rods and the rack & pinion.

I then took a paint pen and marked every bushing/interface with the control arms. I then measured the cross-car and fore/aft distances of the lower control arms. I reinstalled the front tires, backed down the driveway, hit the brakes and "pop", the toe alignment was back in alignment (but the steering wheel was way more off center).

Back in the garage, I removed both front tires and inspected the paint marks. I started with the passenger side since that is where I heard the popping noise when it went out and back in alignment. The upper control bushings shifted 1/4". There was about 1/8" of shift in the lower control arm bushings and there was a rotational shift in the lower shock support.

The driver's side hardly shifted - any shift was 1/8" or less but I think it would be wise to replace all the bushings on both sides. If I don't, my fear is that with the passenger side bushings all replaced, the driver's side would fail in short order due to the age and miles as well as that side would take the brunt of the loads with the passenger side bushings new.

Time to order some parts. I'll post an update after I get the parts replaced.
 

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Thank-you for the update. Like I always say: diagnose, diagnose, diagnose.

You might consider using urethane bushing replacements.

I did it on my TB and love them. I also put them in my Isuzu Amigo.

Can't say they've ever given me a problem and they are easier to install. .
 

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Discussion Starter #9
Thank-you for the update. Like I always say: diagnose, diagnose, diagnose.

You might consider using urethane bushing replacements.

I did it on my TB and love them. I also put them in my Isuzu Amigo.

Can't say they've ever given me a problem and they are easier to install. .
Not a problem - hopefully it will help someone out in the future who has a similar issue with their Trailblazer/Envoy. There's nothing worse than doing a search only to find a thread where someone has the same issue but there's no update. Prior to my post here, I found a post on another forum where a guy had the same issue on his Envoy but there was not any follow up post on what the problem was.

I may consider the urethane bushings but this truck has 160,000 on the clock - if the OE bushings lasted that long, the replacements should last the rest of this vehicle's life...LOL
 

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Not a problem - hopefully it will help someone out in the future who has a similar issue with their Trailblazer/Envoy. There's nothing worse than doing a search only to find a thread where someone has the same issue but there's no update. Prior to my post here, I found a post on another forum where a guy had the same issue on his Envoy but there was not any follow up post on what the problem was.

I may consider the urethane bushings but this truck has 160,000 on the clock - if the OE bushings lasted that long, the replacements should last the rest of this vehicle's life...LOL
I was thinking of ease of installation for you. Urethane is just a lot easier.
 

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I may consider the urethane bushings but this truck has 160,000 on the clock - if the OE bushings lasted that long, the replacements should last the rest of this vehicle's life...LOL
Just remember that it's been 17 years , at least , since the original bushings were made. Are any 'new' bushings going to be of the exact material used then ?
I'd think any improvement over OEM would be well worth a bit extra cost to not have to redo the job , ever . ;)
 

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Discussion Starter #12
I have been working on the right side all afternoon - the upper control bushings weren't bad as far as I could tell. I replaced them since I had all the parts. Advance Auto's control arm bushing tool sucked - it was open at one end and the adapters slipped out of the tool when the jackscrew was tightened. I took that back and got the ball joint press which worked much better.

The lowers - I have struggled them all afternoon... The lower bushings had a visible gap between the rubber and the outer housing. The forward bushing is so large that nothing in the kit will match up to the outer bushing housing.

The bushing/ stud that the shock yoke attaches to was cracked. The only way to remove that one was to use a cutting torch to burn out the rubber and knock out the tapered stud. I used my Sawzall to cut the outer housing so I could knock out the housing.

I plan to take the parts into work tomorrow and use the hydraulic press to install the yoke bushing and forward bushing. This job sucks.... If I were doing it again, I'd buy the lower control arm adapter forging with the bushings installed.
 

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Discussion Starter #13
It's all done (finally!) - all 10 bushings were replaced and the problem is gone. The problem was gone after the RF bushings were replaced but I thought it was best to replace them all.

It looked like the lower bushings had the worst appearance - the rubber was all cracked and there was a gap between the rubber and the outer sleeve. I bet they were the cause of the issue all along. The upper bushings looked fine but since I had the new ones, and because they showed the most movement when the problem occurred, they got installed.

The shock yoke mount bushings had a lot of cracking - even though that would not have contributed to the problem, I replaced them anyway.
 
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