[New2Cadi]

Hi everyone… first time here (or any other car forum).
I will start by saying all I know about a car is where the key goes, and where the credit cards are in case anything goes wrong.
That said, our car is a 1994 Seville and has had a knocking sound right under the passenger seat since we got it a couple of months ago. It is a low and constant thumping, as is louder if we are on a highway and going 50 or more. An important peace of info is that if I hit the brakes, even slightly, it will stop. I had it on two lifts so far and neither guy found the noise. The sound is getting a little louder now and I am beginning to visualize the entire motor being left on the road as we careen into the nearest ditch, and the next mechanic saying “If you only had those two bolts tightened, you would still have your car”!
Any ideas???, and thanks very much for this forum!
Maybe I will finally know something about cars, at least the car we are driving right now…

 

[mhamilton]

Welcome

Have any of your mechanics gone in the car with you to hear the noise? There's not much that could knock under the passenger seat.... my 1st thought was maybe cradle bushings, but not sure that would be constant or affected by braking. Almost would suspect the bearing on that side, or a suspension bushing.

 

[Ranger]

I wonder if what you're hearing might not be an exhaust pipe vibrating against the floor caused by a bad motor mount?

 

[New2Cadi]

I took the advice above and made sure the guy (a new guy) drove it on the highway himself.... not just putting it up on a lift.
He drove it this this morning and by 4PM, I had no noise. It was the "pivot bushing in the right rear upper control arm". Since I don't have a clue what that is, I simply paid the $90. but have a smile on my face now.
Thanks, I will be back here again soon. I have a few minor but important questions about replacing the antenna, a rear tail light, and questions about what headlights to buy for the car. We live on Cape Cod and there is almost no street lights anywhere, so it has never been so important to have good strong "wide-beam" headlights. I will ask this in a new thread.

 

[mhamilton]

Ah yes, the infamous rear knuckle bushings! Very common on these cars. I was almost going to mention those, but since you said the front end noise I figured it was no way. When those go it usually sounds like a bowling ball rolling around in the trunk. Glad your car is noise free

 

[Fishcakes]

I took the advice above and made sure the guy (a new guy) drove it on the highway himself.... not just putting it up on a lift.
He drove it this this morning and by 4PM, I had no noise. It was the "pivot bushing in the right rear upper control arm". Since I don't have a clue what that is, I simply paid the $90. but have a smile on my face now.
Thanks, I will be back here again soon. I have a few minor but important questions about replacing the antenna, a rear tail light, and questions about what headlights to buy for the car. We live on Cape Cod and there is almost no street lights anywhere, so it has never been so important to have good strong "wide-beam" headlights. I will ask this in a new thread.

Didn't I tell you it was a bushing, bro ?? :cool2:

Fish
former owner :shhh:

 

[N*Caddy]

I have a few minor but important questions about replacing the antenna, a rear tail light, and questions about what headlights to buy for the car. We live on Cape Cod and there is almost no street lights anywhere, so it has never been so important to have good strong "wide-beam" headlights. I will ask this in a new thread.

The power antenna is held by one single bolt to the bracket that holds the RIM too(in your '94). Just open the trunk, remove the liner on that side (locate the plastic fasteners) and there is not much to explain - remove the bottom bolt and slide the antenna down. I did posted instructions regarding how to rebuild your power antenna if you think you are up for it here.
The taillight...depends if you are talking about the inner one (trunk lid mounted) or the outer ones.
Inner tail lights come out by partially removing the trunk lid liner and locate the 3 plastic wing nuts holding the tailight assembly. Before removing the wing nuts, on the bottom edge of the trunk lid (underneath the taillight) locate a plastic fastener (Christmas three style) that needs to be removed (pry it out with care, it could be stubborn). Once the clip and the 3 wing nuts are out the taillight comes out all you need is to disconnect the electrical connectors. Also if is you find the harness is not long enough just pull it along with the round rubber grommet, you get an extra 2-3 inches of slack. Don't forget to put the grommet back once you are done or you get water in your trunk.
Outer taillight, partially pull the liner directly behind the taillight locate the 3 wing nuts holding the taillight assembly attached to the car body. Then follow the instructions for the inner taillight (minus the bottom plastic clip).
Lights...I have good experience with PIAA light bulbs, you need 9005 for HI and 9006 for LO.