300M: Front wheel noise while turning

Car is '00 300m.

When turning to the right while moving forward, a scraping noise is
being generated from the front driver's wheel area. Noise pattern
(frequency) is proportional to wheel RPM. The duty-cycle of the noise
"burst" is proportional to the amount of right-hand turn. Noise is the
same regardless if breaking, coasting, or accelerating.

No noise if travelling in a straight line. Does not seem to make any
noise when turning left. Doesn't seem to be any noise from the
front-passenger wheel.

Any candidates for this noise? CV joint or boot?

What exactly is on the scheduled service list for the front wheels for
this car as far as rotating parts go?

 

It's probably just the brake heat shield scraping away against your poor
disk. This is a very common problem with the LH cars, and I've had it
on my '99 since 2003. This shield is a flat metal "tongue" that hangs
down between the bottom of the brake disk (rotor) and the steering
knuckle and has a very close clearance with the disk. For some reason
the clearance gets even less during turns in the direction away from the
wheel's side.

If the scraping is during left turns, it's likely the right wheel and
visa versa. The best fix is to turn the wheel in the direction of the
noise (to maximize the gap while you work) and remove the wheel.
Carefully/gently pry the brake shield away from the disk. I use a thin
piece of cardboard to protect the disk from whatever I'm doing the
prying with. With the piece of cardboard then gently slide up and down
between the disk and shield to loosen the junk and rust that builds up
there.

Unfortunately it's only a temporary fix, although a cheap and easy one.
It tends to keep on reoccurring as the shield rusts and/or collects road
grit. I've given up removing the wheel each time and merely park the
car with the wheel turned all the way, then reach behind the wheel and
use an old hotel key to clean the gap. It tends to reoccur faster when
the car is parked in the rain.

I would take care of this right away as that scraping noise is your nice
smooth disk surface being scraped away. If not taken care of, it
gradually gets worse until the slightest turn causes the noise.

 

I agree with Greg, especially if the noise you are hearing is a
high-pitched squeal.

Greg - I've not heard of the problem continuously recurring like yours
has done. Usually the shield is bent when suspension or brake work is
done, and once it is bent back away from the rotor, it's OK. Weird.

If it's not the rotor shield, the next suspect in my mind would be the
wheel bearing.

The only mention that the FSM makes of checking the front end components
is to "Inspect the CV joints and front suspension components" under the
heading "At Each Oil Change". No other mention of that area under any
mileage heading (I'm looking at the Schedule B in the '99 FSM).

 

Oh, No!!! Not the hated "which side is the noisy bearing on?"
discussion again!!!
It's been soooooo long. )

 

While on the subject -

Is there any recommended service interval (or, is it just a good idea)
to grease the wheel bearings every once in a while on these LH cars?

I remember cleaning and repacking the front wheel bearings on my older
Dodge's with front drums every once in a while because you had to take
the bearings out to pull the drums off while replacing the brake
shoes. I had the impression that the rear bearings (which you didn't
have to remove) were exposed to differential fluid (yes?) and hence were
always lubricated.

 

They are sealed - no greasing possible - sealed double-row balls. The
service interval is that when they start making noise, you replace them.

 

I don't do that anymore.

 

I could swear that when I removed the outer cap on the rear wheels I
could see the cotter pin holding the nut in place, and the bearing right
behind it. Didn't seem sealed to me (not any more sealed as they used
to be in the 60's).

 

The rear does have a cotter pin and nut - that just locks the sealed
hub/bearing assembly to the spindle.

I thought you were asking about the front bearings, but the rears are
also sealed. Both front and rear are hub/bearing assemblies (replace as
a unit).

 

Nor me, since I invented the stethoscope.........

 

Aaarrrgghhhh!!..."I".

 

It could be worn bearings causing the scraping.
At about 80k miles my '95 Concorde developed a scraping of the front
brakes. Turned out it was caused by worn bearings allowing the wheel to
shift and cause the brakes to drag.