Mechanics

LE 2.2 SHAKES WHEN STEPING ON THE ACCELERATOR FROM A LOW SPEED.

1993 Toyota Camry • 173,000 miles

Hi friends,

My '93 Camry has been shaking when stepping on the gas from a slow speed or stop and from what I can tell, others have experienced this with different causes.

For my Camry, if I'm at a stop light at a freeway on-ramp and then I need to quickly get up to freeway speeds, the car shakes and this is felt in the steering wheel. Thus, this problem occurs when I am accelerating somewhat aggressively (for this little motor).

I must first state that I feel I have a good mechanic where I now live in southern California as I have had good experiences with his work in the past. He told me that I need to replace the CV Axles to correct this shaking. The car has about 173,000 miles on it now and I did have the Axles replaced several years ago when the car had 106,000 miles on the clock. I did the replacement at that time because, the vehicle was clicking when making turns and upon looking under the car, I could see the boots were visibly torn (i.E. - From my understanding, the 2 signs of bad axles). Upon replacing the axles years back at 106K miles, the clicking noises ended.

Presently, I'm not getting a clicking sound upon turning the vehicle nor do the boots appear to be torn. Last year I had some work done on the car and did have the engine mounts (top and bottom) replaced as he pointed out the rubber had deteriorated. Therefore, I doubt the engine mounts are part of the problem.

Also, as it was definitely time for 4 new tires on the car, a couple of months back I had new tires balanced and installed which did not noticeably improve or worsen the vehicle shaking problem.

My question is: Is it likely that bad CV Axles are the cause of the car shaking like this? I am about to begin commuting a significantly longer distance soon and as my mechanic hasn't steered me wrong over the 2 years I've gone to him, I am leaning toward getting the work done. I would like to get your thoughts as I haven't heard of this shaking being a symptom of faulty Axles. Is this possible?
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Richbal
May 30, 2013.




Your mechanic is right but the problem in this case is due to wear in the inner cv joint housing. I prefer to disassemble the inner joints and look for the wear rather than replace both half shafts. It is not unheard of to get a rebuilt assembly with a worn housing that got overlooked. Then you'll have the same problem and incorrectly assume the mechanic diagnosed the problem incorrectly.

Once you have the housing apart and cleaned of all the grease, there are six highly polished rolling surfaces the rollers ride on that must be checked. If you can feel the slightest waviness on any of those surfaces you really have junk. Normally you must shine a light in there and look for the slightest irregularity in the reflections. If you see a tiny wave in the reflection and you're not sure that's the cause of the problem, ... It is.

Those rollers have to run back and forth in the housing as it rotates. That allows the shaft to change length and angle. When accelerating, the torque makes it harder for the rollers to move over the raised areas so they tend to bind. When the shaft can't change length freely it pushes and pulls on the spindle as it rotates. That tugs on the lower control arm which is mounted on rubber bushings. The steering linkage is also connected to the spindle so as it gets pushed back and forth, it tugs on the steering linkage causing the shimmy you feel.

Replacing engine mounts can cause this problem to occur. The wear is already there in the housing but at least one engine mount sets the location, side-to-side, of the engine and transmission. Repositioning the engine just a little one way or the other will change the area the rollers run in and that is when the problem may occur. The engine mounts didn't CAUSE the problem. They merely caused it to become evident. You may reduce the shimmy by repositioning the engine mount but that's not really addressing the main cause.

Most of the time a new inner housing from the dealer is real expensive, often two or three times as much as the cost of a rebuilt half shaft. That's why to save time and therefore your money, many mechanics don't waste it inspecting parts. It's less expensive in the long run to just replace both shafts than it is to identify the bad one and replace just that one.

Caradiodoc
May 30, 2013.


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