96 Stratus: Rumbling noise

My Stratus(2.0L, 5spd) has developed a very annoying rumbling noise at
anything above 15 MPH. At first I thought it was tire noise, possibly
cupped tires due to a longer than usual rotation interval. But switching
the wheels/tires(205-55 16s) with an extra set(185-75 14s) didn't make a
significant difference.

The noise is significantly worse when I go around a gradual left turn at 40+
MPH. It seems to settle down at highway speeds(70+), but I can still hear
it.

It happens whether the car is in gear, or not. With the clutch depressed,
or released.

There is no noise when I am turning the wheels to park the car.

So I'm wondering what the possiblities could be, before I take it to my
trusty mechanic.

Any opionions would be greatly appreciated.

J. Lock

 

Sorry my friend, but it sounds like you have a bad wheel bearing.
Since the noise is worse on a left curve, my guess is it's the right front
wheel bearing that's making the noise.

HTH
Giz

 

I agree with Giz that it sounds like a bad wheel bearing, however, if it
gets worse when turning left, then it is the left bearing that is bad.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

Assuming your both correct, and with a avg labor rate of $80/hr, how much
should I expect to pay to have one these replaced?

One more thing. I thought front wheel drive cars had only CV joints in the
front. Where would the bearings be? I can't picture where the spindle
would be that a bearing would be pressed onto in the front of one of these
cars.

Thanks fot the help.

 

I'm a little shocked that the other two posters disagreed on which bearing
was bad. If it's louder turning left, then it's louder when there's more
weight on the right bearing. Thus, it's the right bearing that's bad, as the
first poster stated. I think the second poster just forgot to imagine what a
left turn is.

You have no spindle. The CV joint is inserted though a hole in the middle of
the bearings and engages splines on the inside of the hub. The bearings and
hub are porbably an assembly (I don't have a stratus, don't hold me to it).

 

This takes a little more concentration, visualization, and attention
span than most people care to invest to understand. As much as people
hate that, some things in life are just like that. 8^)

What happens in a left turn is that the right front suspension does in
fact see additional weight (forces) on the wheel and bearing, **BUT**
*PART* of the resulting forces is in the opposite direction. So why
does that matter? (If interested in following this thru to the end, one
may wish to make some simple sketches of a wheel and bearing (inner &
outer races, and balls) while reading the following)

Picture the stationary (outer) bearing race in the hub. The noise is
typically due to brinnelling of the contact surfaces of that race *AT
THE TOP* inner (meaning towards the engine) ball contact surface of the
race, and *AT THE BOTTOM* on the outer (meaning towards the curb) part
of the race (as the balls roll over the rough brinnelled surface, the
noise is generated), with the overwhelming part of the forces being on
the top part of the race (supporting the portion of the weight of the
car that is on that wheel), and the rest of the forces being a twisting
moment that pushes the top part of the wheel inward, and the bottom part
of the wheel outward. That is the force situation in straight and level
driving.

Now focus on the left bearing during a *left* turn. While it is
certainly true that the weight of the car supported by that wheel is
lessened (shifted over to the right side), there is a large twisting
moment (due to side forces) on the left wheel that pushes *very* hard on
the bottom outer part of the bearing seat and also on the top inner part
- the part that is brinnelled from carrying most of the load for its
whole life - so the noise gets amplified form the increased pressure of
the balls on the brinnelled top inner part of the race, or a bearing
that is not brinnelled enough to be heard or felt over the normal
vehicle noise suddenly becomes audible while turning left.

NOW - picture the same (brinnelled, noisy) left bearing during a right
turn. While it is true that the total downward force is increased on
the left wheel, the *TWISTING MOMENT* is in a direction that takes most
(or, in a hard turn, close to all) of the pressure off of the inner top
(brinelled) part of the seat and shifts it over to the non-brinnelled
top outer ball contact surface of the seat, and so it gets curiously
quiet during right turns (because the balls are pushing hard on the
smooth (non-brinnelled) contact surface of the outer part of the top of
the race) with decreased pressure on the inner top (brinnelled) part of
the race.

In 7 out of 7 noisy front bearings that I have replaced on my own
vehicles in my years of driving, this rule has never failed to pinpoint
which side to replace the bearing on. Replace the bearing that is on
the side that you turn to to turn the noise on, and opposite the side
you turn to to turn the noise off.

It will be interesting for the OP to post back when he has the problem
solved as to which bearing was the noisy one (assuming that it is a
bearing - which it almost has to be form his description of the
behavior).

If anyone is still reading, to add a little to what Joe said about where
the bearing is located on FWD cars, if you take the brake rotor off, you
are looking at the hub that the bearing is mounted in, attached to the
steering knuckle.

Interesting how, as Joe points out, that the car repair trade often
continues to refer to the knuckle as the spindle when technically there
is no such thing on the front of an FWD car (old habits...).

What used to be the stationary spindle in the old days has been replaced
by the non-stationary (rotating) axle. The term "steering knuckle" is
correct in either case, but the term spindle (as in "stationary
spindle") does not apply to the front wheel of a FWD car (not to be
confused with the fact that the rear wheels of FWD and RWD cars both
have (stationary) spindles). 8^)

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

I would expect the bearing to run about $100 for the part and @ $80 an hour
I would expect about $160.. so if you get off @ about $250 I would think
that is about correct.. Although any mechanic worth his salt could probably
do this in an hour.

 

Interesting write up...

Having replaced hundreds of wheel bearings over the years, all I
can say is that there is no set pattern to how and under what
circumstances a damaged wheel bearing will become louder audibly.

Sometimes they get louder when loaded, sometimes they get louder
unloaded.

The best course of action is to determine which -end- of the
vehicle the offending bearing is located at, raise that end of
the vehicle and listen to the rotating bearings with a
stethoscope to pinpoint the bearing that needs replacing.

 

Most likely translation: You disagree. 8^) No problem - our experience
is different.

For the 7 front bearings I have replaced over my lifetime of driving, I
have never had a bad rear bearing (though I know they can go bad,
especially on late model Subarus due to factory problems). Point being
that rear bearings in general are much less likely to be the problem
than fronts, therefore my focus on diagnosis of the fronts.

I still say 7 out of 7 is a pretty good record for a method that is
claimed not to be so good. 8^)

I can say that I have never had success at determining a bad bearing by
listening while spinning the unloaded wheel - though I admit I have
never used a stethoscope for that.

You didn't mention it, but I often see people advise to jack the wheel
up and look for play in the bearing while trying to wiggle the wheel
when trying to identify a bad bearing. I can say that I have never had
a bearing get to the point where there was any noticeable play - I guess
I have sensitive ears and always get to it before it gets that bad.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

Most likely translation: You disagree. 8^) No problem - our experience
is different.[/QUOTE]

Most likely wrong:

Gee, I replaced more than 7 wheel bearings in February.

That's a very small sample size, and in retrospect, I believe
that the first seven + that I replaced were ably diagnosed by
similar methods to yours. It's the one that doesn't follow the
diagnostic rules that brings you to your senses and demands that
a better method be utilized.

With a little bit of experience and practice, one can learn what
a normal bearing sounds like when unloaded, a damaged one, even
unloaded will have characteristic sounds that are easily
recognized. takes a little more effort, but after you've bought
a few wheel bearings that weren't needed, it's well worth it.

I didn't mention it because your post wasn't addressing
diagnosing a bearing in that manner.

Well Bill, not everyone works on their own vehicles, and not
everyone has hearing that rivals a dogs. Thusly, yes, I have been
able to diagnose a bad wheel bearing by using the noticeable play
method, but having been in that situation is hardly a reflection
on me personally.

 

Most likely wrong:[/QUOTE]

You gonna start this kind of one-upmanship crap again?

That's nice. I didn't know this was a bragging contest.

Like I said, it will be interesting if the OP posts back with what was found.
I will be very surprised if he doesn't find out that the left front bearing is
bad, but no big deal either way. (Probably no detectable play in the noisy
bearing either.)

That wasn't a criticism. Everything I posted was not in response to or about
you.

Actually it's not all hearing - you can generally feel it thru bodily contact
points (steering wheel/hands, seat/butt, floor/feet), and my hearing is not
all that great - something to do with Led Zeppelin and the use of headphones
when I was younger, I think.

I was not implying or even thinking that it was. I was merely thinking that
if someone is aware and in tune enough with their vehicle to be posting here
about bearing noise that they notice, that it has probably not been going on
for the period of time that it would take to get to the noticeable play stage
- noise/vibration would have been noticed if anyone was even slightly concious
long before that in the overwhelming majority of cases.

Now the average consumer that is bringing a vehicle into a repair shop may be
a different story - they very well may wait until the bearing is about to come
apart and the rotor is turning tilted in the caliper to bring it in for
diagnosis.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my address
with "x")

 

I agree sounds like a wheel bearing