I've been trying to find out what the source of the instability
when driving down bumpy roads. I thought it might be a suspension
component (watt's linkage). It was suggested that tires may be the
problem. A rear tire was 10 psi low. I hadn't checked it for over a
month and probably damaged the sidewall from some aggressive
cornering. Tire center checked in water and no leak. That means air
is escaping during driving. I noticed that more air escapes the
more aggressive the driving (for some reason I've never experienced
this type of problem before). These are Michelin energy LX4 on an
04 Town Car. The car was bought used at 36.5K miles in Feb 07 and I
didn't put the tires on. They're dated 43rd week of 06. The TC now
at Oct 07 has 44Kmiles. The tread are ~1/4". Michelin said I
should have a tire removed and inspected for damage. I tell the guy
at Sears to do it and he looks at the tires and says it's something
else - didn't see the need to look inside.
Struts and shocks were replaced with KYB (551600 strut, 551601
shock in 07 cat.) and front end aligned. No loose suspension
components were detected, even after several inspections at various
places. Problem still exists. There's that irregular lateral
movement over bumps. Shocks have nothing to do with lateral motion.
It was never there until a few months ago.
So maybe I should get rid of these tires and consider what they put
on a CV interceptor. Hell, I already ruined that "Town Car ride"
with KYB urethane strut and shock mounts, which only made the bumps
more noticable, but didn't help cure the problem. Why not just
change to some less comfortable tires that have more durable
It doesn't make sense. I called one limo/livery service at random
and the mechanic says they just go to sears and have michelins put
on - didn't say which model though. So, I have 44k miles and those
livery cars go 200k-300k.
The new dampers and mounts apparently increased city mpg from 16.2
to 17.4. Big-O tires decided to set the fronts to 35psi. The
sticker says 32 front 35 rear, but Big-O says it's for the "dealer
ride". That's comical. I suppose Ford has the sticker just for the
test drive and the shops know better. The service advisor at the
dealer didn't seem to care, however. I guess it's safe to set the
fronts anywhere between 32-35.
Thanks for any suggestions
What kind of rims are on the car? If it has any sort of Aluminum
rim (cast or forged), you can easily get rim edge leaks at the beads,
all it takes is a scratch in the seal coatings on the tire seating
area of the rim.
You can also have cracks/porosity in the wheel rim casting itself
that will leak up through the wheel and come out on the inside of the
rim - the inside of the rim is normally coated with a layer of epoxy
as a sealer, but that can get damaged and allow a leak.
The tire place is normally only looking for bubbles from the tire,
and the tire bead area. Unless they submerge it all the way and
deliberately look for a bad and leaking RIM, they won't see it.
Steel rims can also develop cracks or leaks, but it's a lot less
common. And the car is too new for fatigue cracks in the rims, the
only thing that could cause that would be physical damage. Has anyone
slid your car sideways in the rain or snow lately, and found a curb
the hard way?
Or a huge pothole with the back bumper of a Beetle sticking out?
Police cars use regular tires - just ones with a higher speed rating
and a more aggressive tread pattern.
Limos are much heavier because of the extra 4' of body they spliced
in, and are often using "Extra Load" P-series (passenger) car tires -
which are constructed just like Light Truck tires with heavier
sidewalls and more sidewall and tread ply reinforcement.
The difference being they don't have the big letters on the sidewall
and you can get whitewalls - big whoop. Anything with a higher load
rating and more plies is going to ride stiffer.
Extra Load P tires are usually Special Order only - but you can get
a good selection of Light Truck tires with 'highway' tread patterns
right off the rack at any decent tire shop. Have them mounted 'white
letters in', and nobody will know.
Huh? Shocks and struts aren't going to affect fuel mileage *that*
much, unless they cured a big alignment problem at the same time.
If you change tire size or load rating you need to modify your
pressures from the doorpost sticker values - get a copy of the
Load/Pressure chart from the tire store for your new tires. Then get
the vehicle weighed for Axle Weights at a truck scale when it's loaded
the way you normally drive it, and adjust pressures to match the load
chart. (Tire Load = axle weight/2 )
But before you start condemning the tires, get them rotated front to
back, and see if the problem moves with the tires. Might just be one
tire with internal belt problems, and you can isolate and replace it.
--<< Bruce >>--
They are lincoln 14 spoke aluminum. Don't know if cast or forged.
That' s what I'll have done. I don't know why the tire center didn't
look into repairing the rim or just reseating the tire.
Not by me but I don't know the whole history of the car. It's not too
fast a leak. If I check every two weeks it'll be OK for now.
I should have clarified. I meant the livery service (that limo
services also offer) which uses the "L" Town Car that is 6" longer
(159 lbs heavier in 04) than the standard sedan for more legroom in
back. Other than that there's no difference; their gross weights are
That's what the dash is showing. I didn't have bad alignment. Perhaps
I'm being lighter on the gas lately with the problems. And another
dealer (Ford, not Lincoln Mercury) said not to set the fronts to 35.
I just had the tires rotated and balanced. There was little
Today I brought it in to a Ford dealer. (the Lincoln dealer service
advisor was probably sick of seeing me) The service advisor took it
for a test drive (the 3rd test by various mechanics) and on the
highway he said the car is dangerous. There is definitely a problem
with the rear suspension with all the lateral movement. He didn't see
problems with the tires. He said they have a guy that specializes in
suspensions. It will be very interesting to see what they find 'cause
I had it inspected twice and nothing shows visually.
I hope this stuff helps a bit...
At that mileage, there shouldn't really be any problems in the suspension.
Usually a low tire of bad alignment will cause what you describe. I am a
little surprised that the tires are newer than the car since factory tires
on those things usually go 60-70k. You might want to have a good tire shop
actually dismount the tires and check them if you think you really hurt
them. Did this behavior come with the car or start later?
Tire pressure settings front and rear are subjective to a point. My
experence in the last 10-20 years is that cars ride and handle best at the
inflation on the door sticker. All bets are off it the tire size is changed
from spec, tho.
Does the car pull at speed or when you brake? How about vibration or
excessive road noise? A good independant tire and suspension shop can
sometimes work wonders...
Good point. Why the original owner had to replace the tires so
early on. I didn't ask them at the time since I wasn't aware they
were so new.
The problem started in about 6 months (purchased 02/01/07 w/36.5K).
It's at another dealer now. The advisor took it for a test drive
and on the highway and said it handles like crap and is dangerous.
There's lots of lateral movement coming from the rear that also
affects directional stability. Now he didn't see a problem with the
tires. The front end and tires were OK as he rocked the steering
back and forth on the highway. It corners mostly flat on the
entrance ramp so the sway bars are working. He even noticed that
when first getting into the parked car, it rolls or sways more than
it should which indicates a problem. I had two prior visual
inspections that found nothing broken or bent.
No pulling during braking. No vibration. The tires make a little
I ordered KYB gas-a-just and strut and shock bushings which are
urethane. Big-O installed them two weeks ago. It made no difference
to the lateral motion problem in the rear. Of course they had to
align the front end and didn't find any worn parts. The KYB parts
are listed for the 03 thru 06 Town Car in their 07 catalog. They
are correct parts for the car and are not causing any issues.
It may have 44K on it but I probably broke something. I never do
donuts or brake torques, or squeal the tires on turns. However I
once got my foot caught between the brake and accel pedals. First
and last time this ever happened. This caused one wheel to spin
while desperately applying the brake trying to avoid going into the
car in front of me at a stop light in traffic. The traction control
light was blinking. After about 15-20 seconds of this I thru it
into park and naturally took my foot away from the pedals. I had
previously read in a customer report where the writer thought the
car had a defect and would accelerate unexpectedly, but the dealer
said this occurs to some people (w/big feet?:)) with E-frame cars.
Once aware of what really happened it doesn't occur again.
If a leak can't be found with a trip to the dunk tank, smart money is on
looking inside the tire (look - don't run the hand around inside). Often,
one can find a nail or similar that wont leak if the tire stops in the
"right" place.... and no obvious signs of a puncture on the outer surface.
Take it apart and there it is...
At the same time, the bead surface of the wheel can be inspected for
damage/flaws as well as the bead of the tire... But most times, it will be a
puncture not visible from the outside.
Your tire guys sound a tad lazy....
I should have insisted on a through inspection. Right now it's at a
dealer. The advisor test drove it and says the rear suspension has
got problems and is dangerous on the highway. I've had it test
driven two time before and only one said there's a little hopping
on some bumps. (see my other post) So now it's about suspension and
will probably learn tomorrow about it.
Another possibility is the steel belts starting to come apart inside
the tire casing - running your bare hands along the inside of the tire
is NOT advised until after a thorough visual inspection with proper
lighting, and then feel for sharp bits with sturdy gloves on.
You could hit some steel wires that will flay your hand but good.
But I'll bet if you get a mechanic that agrees there's something
seriously wrong (and isn't NOT looking for a non-problem to make the
corporate folks happy*) is going to find something. A broken weld on
that locating rod bracket, or another suspension anchor point that is
floating when it should be solid...
(* - If you are looking for a problem you can find it. If you are
looking to NOT find a problem, you can overlook all the clues pointing
to the problem as anomalies.)
--<< Bruce >>--
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