How to Repair

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Cadillac Repair Sloppy Ride

 Sloppy ride- 99 Seville Fixed  Jim Fogarty  6:29 pm sunday march 17, 2002
I just fixed a problem with my I just fixed a problem with my 99 Seville's ride that I want to share with others.

I have the car one month. I noticed that the ride was poor, leaning on turns and feeling like bad shocks when bumps were hit. The rear end would almost fish tale on a bad bump.

There were no warnings about Road Sensing Suspension, no codes stored. The test for automatic level control, as described in the manual, passed with flying colors. So why the bad ride?

There were no GM service bulletins to help.

It turns out that the automatic level control and compressor system shares its sensors with the road sensing suspension. That seems reasonable, no sense having the extra sensor as on cars
without RSS.

Having restored several classic cars, I decided to measure "trim
height". This is the distance to ground on each side of the car
from the unibody frame. The specs were in the manual. According
to the manual, the car was within spec, but different side to

Then I looked at the RSS sensors on each side. These go between
the body and lower control arm in the rear. The book said to
check for disconnected or bent links. All were fine.

I did the leveling test again and found the trim height on one
side to be 3/16" below the other when leveled (following
compressor shutoff). They were well within spec, but suspicious.

The sensors have arms that come out that almost look like a
balance scale. I looked at both sides. The right arm was level,
the left sensor arm was slanted about 10 degrees more than the

After figuring how it should work, I worked on the one that was
level (the right side), assuming that it was telling the RSS
module that the car was level and at proper trim height BEFORE
it should have. I was right.

The RSS sensor mounts with one bolt. It aligns with a tab that
goes into a small round slot at the bottom. THE RIGHT HAND
SENSOR WAS IN THE SLOT BUT TWISTED clockwise about 5 to 10
degrees. I loosened it, rotated it counter clockwise and
tightened it in. I backed up the car, shut it off, then on, to
let it re-level again.

The trim height went up almost 3/16 of an inch. I wasn't even
out of the driveway when I knew the car was fixed and the ride
problem solved forever. I drove it about 15 miles on smooth
roads, very bad roads, and turns, and it is as stable as my 1994.

This car must have been this way from new. It has 44,000 on it
now. The last owner never did get to feel how wonderful this
suspension really is.

SO.. If you have ride concerns and there are NO CODES to fix
first, make the following SIMPLE check:

No weight in car or trunk.

Park on a level surface, key off.

Turn key on, do not start. Allow one minute for car to level.
The compressor runs only a few seconds.

Look at the RSS sensors. They are located in front of both back
wheels. They look like a balance scale. They should be almost
perfectly level. If one is off, you may have the same problem
that I did.

To fix it:

Find the sensor that is twisted in the mount and straighten it
as much as possible. You can level it with the play you are
given by GM. Be sure to work on the side that looks right to
begin with. It is the problem side.

I hope this explanation helps some of my Caddy friends!

Jim Fogarty
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