My 95 Chev C1500 truck with 135,000 miles doesn't steer like it used to, and it is wearing the outboard edges of the tires. I checked all the linkage for excessive play, but so far have found none. Could control arm bushings cause this? The front end doesn't make any noise, like clunking or sqeaking, and the handling of the truck is not too bad, just not like new anymore. How would you check for wear in the control arm bushings?
Thanks, Ros
Good change many of the rubber bushing in the suspension are dried up.
Has the truck been aligned lately?
Roscoe Coaltra> My 95 Chev C1500 truck with 135,000 miles doesn't steer like it used
Has never been aligned - never needed alignment before. No curb collisions, etc. So how do I check the bushings - something had to change to cause the edges of the tires to start wearing.
My car's engine has never seized up. never needed an oil change before.
The outboard edges of the front tires is normal. This is due to cornering forces. Next time you get tires, it might be worth it to go ahead and get an alignment. With a truck, you only need a thrust alignment. Don't let them cheat you into paying for a 4 wheel alignment.
-Bruce
Bruce Chang wrote in article ...
Bruce:
If Roscoe takes your advice and asks for a "thrust alignment", he will be getting and paying for a four-wheel alignment.
A "thrust" alignment aligns the direction in which the rear wheels point - or the line/angle upon which the vehicle's forward thrust is applied on a RWD vehicle.
Thrust line/angle determination requires measuring certain rear-wheel/axle location parameters. You must work with the rear wheels/axle to measure/correct thrust angle, ergo, it is, by definition/default, a four-wheel alignment situation to measure/set the correct thrust line/angle in its relationship to the chassis and front steering/suspension.
It can be done with string (many racers have done thrust angle alignments this way for decades, and continue to do so), four-wheel alignment equipment, and/or laser line generating tools.
"Thrust alignment" is the RWD equivalent of the four-wheel alignment so common on FWD cars with IRS rear suspensions, and is, therefore, more complex and costly than a simple front-end alignment.
I believe you may have intended to suggest a simple "front-end alignment", or FEA, but got carried away trying to use trade jargon.
Bob Paulin - R.A.C.E. Chassis Analysis Services
It sounds like you're right. As I understand it the rear of this particular truck is not adjustable, at least easily adjustable via eccentrics or tie rod adjusters as with other rearends and therefore when I say thust alignment was still an alignment as you've defined it as "line/angle that the vehicles' forward thrust is applied." Since the rear wheels will not be adjusted, it's a thrust alignment, not a 4 wheel alignment. If I've used the wrong term, I apologize.
-Bruce
Bruce Chang wrote in article ...
As long as you understand that if you come in and ask me for a "Thrust Alignment", you are going to pay more - and get more - than if you asked for a "Front-end Alignment".
The ONLY way it can be a "Thrust Alignment" is if the thrust line/angle is, at the very least, measured and determined to be within specification. A standard front-end alignment does not measure/affect the thrust line/angle, so there is really no way that it can be considered a "Thrust Alignment."
In a "Thrust Alignment", I'm going to go through the process of measuring/determining the thrust line/angle, and rear wheel camber and toe-in/out situation (determines if there is a bent rear axle housing that might be affecting the thrust line/angle and causing problems), and, possibly, look for a roll-steer condition that might be caused by bent suspension-locating components....
....all the above IN ADDITION TO measuring/adjusting the front-end Caster, Camber, SAI, Toe-out-on-turns/Turning radius, and Static Toe-in settings which are all standard components of a "Front-end Alignment."
As you can see, there is more being done in a "Thrust Alignment" than in a "Front-end Alignment", so the terms are really not interchangeable. A "Thrust Alignment" needs to include a "Front-end Alignment", but a "Front-end Alignment" only doesn't include a "Thrust Alignment." And, the rear axle thrust measuring procedure may take as long as - maybe even longer than - measuring the rear wheels in a four-wheel alignment on a computerized alignment machine, so you will likely be paying as much as - or more than - a typical four-wheel alignment for your "Thrust Alignment", since the labor and cost will be more than with a standard front-end alignment.
In a Thrust Alignment, the thrust line/angle might be "adjusted" by heating/bending components and/or replacing components - making it much more difficult to "adjust" the angles than in a standard four-wheel alignment, and we are, in fact, doing measurement and adjustment that is much more akin to a four-wheel alignment than a front-end alignment.
In a large percentage of RWD situations - perhaps including Roscoe's, a standard front-end alignment is sufficient, and a "Thrust Alignment" is usually only considered when a vexing tire wear/handling problem presents itself and is not readily cured by more common procedures.
But, doing a standard front-end alignment does NOT constitute a "Thrust Alignment" - not if the thrust line/angle and other contributing parameters are not, at the very least, measured/determined.
If you ask me for a "Thrust Alignment", you will get more and pay more than if you ask for a "Front-end Alignment" which will not consider or affect the thrust line/angle in any way, shape or form.
Since the actual rear wheel thrust line/angle won't be measured and/or adjusted, it is a "Front-end Alignment", not a "Thrust Alignment."
Also, since there are more opportunities to make easy changes, thrust line/angle is a component that SHOULD be measured/adjusted as a part of a standard "Four-Wheel Alignment".
I get the sense that you are a somewhat-knowledgeable automotive enthusiast rather than a professional who actually works full-time and derives his income from the automotive service and repair industry.
Nothing wrong with that, and I am not flaming, but it would appear that you have acquired your technical information and terminology more from consumer/enthusiast-oriented sources than from professional sources.
Of course, no matter what you ask for when you walk into my shop, I will question you about what particular problems you might be trying to correct in order to determine if what you are asking for is what you really need, and that it will, in fact, address the problem you are having.
You won't hurt my feelings if you insist on only doing a certain procedure, but if you do, and I feel it will not address your problem(s), I will invite you to take the vehicle elsewhere. I don't want you coming back saying, "You did this, and it didn't fix my problem", when, in fact, I had suggested that you needed to do "this" AND "that" to properly rectify the problem you described.
Walking into ANY professional shop and telling the people exactly what to do to the car with the unspoken expectation of them guaranteeing that they have fixed your problem is unreasonable....in ANY industry.
I used to have a stamp that stated, "Work not guaranteed - Performed to customer specifications", for people who would come into the shop and say, "I want a Front-end alignment only...No more!"
I now simply refuse to work to their specs, and let the guys down the street and across town have that headache.
Bob Paulin - R.A.C.E. Chassis Analysis Services
I fully understand your point of view and you are the professional, I am not. In my experience, I have worked only with the Hunter series alignment system. As far as I understood, after mounting the 4 heads on each tire, the computer calculated the angles and gave the user (me) the factory specifications and a target zone that I was to adjust to. I'm not saying you're wrong, I'm asking to see if I'm wrong.
My understanding is different from yours and I want clarification as to why you think I'm wrong. I can understand that a front end alignment is different. With the hunter alignment system, there was no front end alignment only.. It was a thrust alignment because the 4 heads had to be mounted to do the alignment. I'm not saying this is the most efficient way to do it but that was the way I was taught and that's what my boss expected of me when I performed an alignment. Obviously there are other systems that don't require a front end alignment to be a thrust alignment. This one did.
Thanks for letting me know,
-Bruce
Bruce Chang wrote in article ...
Bruce:
First of all, current alignment machines are, more and more, being designed to be used by people with few technical skills - no offense.
They are advertised in trade publications as requiring as little as an hour's training in order to have someone "...up and running, doing alignments and producing revenue and rapid repair bay turn."
In fact, it could be argued that computerized alignment allows a technician with lesser skills to work on your car, thus giving you a lower quality job.
They require annual software updates with each car's specifications, and will not usually allow the tech to "adjust" specs to compensate for unique circumstances, and still give a "pass" printout - not that most of today's alignment "technicians" know enough about suspension geometry to be capable of adjusting specs for unique circumstances. They set a vehicle to wherever the computer tells them to set it, and if a problem persists, they are really lost.
There is no real advantage to the consumer in "computerized alignment" over an experienced alignment technician who understands the theories, regardless of the perception that advertising has created.
While today's alignment machines allow for a quicker setup and initial measurement readout, a good alignment tech doesn't need computers to do his/her calculations and measurements.
Computerized alignment machines are more of a benefit to the shop owner seeking rapid repair bay turnover than to the car owner seeking quality work.....but, I digress
Current computerized alignment machines are designed for four-wheel alignments, thus requiring the mounting of four projectors or "heads" to send the complete information which the computer is expecting to receive, and needs to make its calculations.
On the other hand, I am still using an old-fashioned two-wheel rack with which I can work on front-end angles only, not ever paying attention to the rear wheels. Yet, I have been doing "four-wheel alignments" on race cars for more than four decades on this and similar racks.
And, yes, I STILL back Corvettes up onto the machine to do those IRS alignments.....
I sometimes get work from the people who own the computerized machines that cannot figure out a problem.
I think your confusion comes from the fact that you are using the rear heads to set the front wheel alignment relationship to the car's existing thrust line/angle so that the steering wheel remains straight and level when going straight down the road.
Before rear wheel projectors became so common, there were a number of different ways to set the steering wheel in the straight-ahead position while setting the toe-in. Many are still used today. It wasn't called "Thrust Alignment" then, and it still isn't "Thrust Alignment" today..
Quite honestly, with the rear suspension on RWD cars pretty much fixed - as you pointed out - thrust lines/angles were only ever considered when a vexing problem presented itself - as I pointed out.
The term has come into more common usage with the introduction of IRS and the need to measure/set the thrust line/angle when adjusting/aligning the rear suspension on IRS cars - or, more accurately, the potential to screw up thrust line/angle settings by adjusting camber/toe on IRS cars..
With rear projection heads, you can line the rear axle up with the front wheels so that your steering wheel will be straight when travelling down the road - regardless of its thrust line/angle.
In this situation, the car could actually "crab" down the road due to mis-aligned thrust angle relationship between the rear axle and chassis, yet have a steering wheel that is sitting perfectly level and straight since the front-end has been set to correspond with the existing thrust line/angle.
In the situation you describe above, you are simply adjusting the relationship of the front-end steering geometry to the existing rear axle thrust line/angle - regardless of whether that trust line/angle is correct or incorrect - in order to have the steering wheel sit straight when going down the road.
That is what was done long before the term "thrust angle" had worked its way into the automotive vocabulary, and it is still what is being done today.
Aligning the front wheels and rear wheels to track in such a way that the steering wheel is straight and level is a common-sense component to any good front-end and/or four-wheel alignment.
While, in the above described situation, you are adjusting the front-end alignment /thrust angle relationship, it is NOT an adjustment of the thrust line/angle-to-chassis alignment itself, so it cannot be called a "Thrust Alignment" since you have not measured/changed the thrust line/angle - only adjusted the front end steering geometry to work with the existing thrust line/angle, be it right or wrong.
The car could go down the road with the steering wheel straight and level due to your work in matching the front to rear tracking, but still have a severe thrust line/angle problem.
IMHO, saying that you have performed a "Thrust Angle Alignment" - which you really have not - is inaccurate at best, fraudulent at worst.
Some of the chain tire and repair shops like to call it "computerized thrust angle alignment" in order to make it appear to be more than it actually is - a simple front-end alignment.
Bob Paulin - R.A.C.E. Chassis Analysis Services
FYI - I am being redundant with the term "thrust line/angle" since, in talking with people around the country, I have discovered that some prefer the term "thrust line" while others prefer the term "thrust angle", and I don't want to start a debate on the subject. In my mind, the terms are, pretty much, interchangeable, and I understand people whichever term they are using.
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