technical information
Thread Starter
Cruising
Joined: Feb 2012
Posts: 11
Likes: 0
From: Orange Beach Al.
technical information
Need help diagnosing a "grinding Noise" (sounds like rear axle touching under body) not metal on metal.
Car is 76,000 mi, 64 posi-traction 250 HP, with one previous senior owner who says noise has been there a long time. I have put 2100 mi on the car in two plus years I've owned it with no change in noise. One mechanic suggested carrier bearing but I'm reluctant to begin repairs without a better idea. Any help is appreciated.
Gary
Car is 76,000 mi, 64 posi-traction 250 HP, with one previous senior owner who says noise has been there a long time. I have put 2100 mi on the car in two plus years I've owned it with no change in noise. One mechanic suggested carrier bearing but I'm reluctant to begin repairs without a better idea. Any help is appreciated.
Gary
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Need help diagnosing a "grinding Noise" (sounds like rear axle touching under body) not metal on metal.
Car is 76,000 mi, 64 posi-traction 250 HP, with one previous senior owner who says noise has been there a long time. I have put 2100 mi on the car in two plus years I've owned it with no change in noise. One mechanic suggested carrier bearing but I'm reluctant to begin repairs without a better idea. Any help is appreciated.
Gary
Car is 76,000 mi, 64 posi-traction 250 HP, with one previous senior owner who says noise has been there a long time. I have put 2100 mi on the car in two plus years I've owned it with no change in noise. One mechanic suggested carrier bearing but I'm reluctant to begin repairs without a better idea. Any help is appreciated.
Gary
Le Mans Master
Joined: Feb 2001
Posts: 6,317
Likes: 289
From: Ocala FL
If your rear end has been changed some time long ago, they may have used a C3 automatic rear with the larger u-joint flange. They work, but clearance is tighter on the C2 body. As long as all is good with the rubber bushings, all is good on clearance. But a little wear, and you can have them rubbing body.
Also, the floor is normally about an inch above the cross member in the rear, but if you've had too much weight, or body mount cushions have flattened, you could be rubbing there, also, transmitting frame vibrations into the body.
Also, the floor is normally about an inch above the cross member in the rear, but if you've had too much weight, or body mount cushions have flattened, you could be rubbing there, also, transmitting frame vibrations into the body.
Drifting
Joined: Jun 2006
Posts: 1,600
Likes: 181
From: Durham ON
First thing I'd check is the rubber cushions where the front of the diff nose bracket attaches to the frame crossmember; when they deteriorate, that joint becomes metal-to-metal and transmits a lot of noise into the frame. It can also allow the ends of the rear driveshaft U-joint trunnion to contact the top of the tunnel, especially if the floor is sagging.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
A sagging floor is usually caused by loose rivets where the bottom of the luggage stop panel is attached to the underbody, sometimes aggravated by a crack in the top of the tunnel. Permanent fix is to re-rivet the bottom of the panel to the floor, which may require drilling new holes; temporary fix is to put a hockey puck between the underbody and the top of the crossmember on both sides.
Team Owner
Joined: Apr 2012
Posts: 47,628
Likes: 65
A sagging floor is usually caused by loose rivets where the bottom of the luggage stop panel is attached to the underbody, sometimes aggravated by a crack in the top of the tunnel. Permanent fix is to re-rivet the bottom of the panel to the floor, which may require drilling new holes; temporary fix is to put a hockey puck between the underbody and the top of the crossmember on both sides.
I've been looking for a replacement, but don't know what it's called (is that piece what you're referring to above?), and can't figure out who sells it. Any source for OEM? For some reason, when my car was raced in the 70's, they cut out the center section, then someone screwed in plywood to fill, but this sections seems to sag regardless.
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Drifting
Joined: Jun 2006
Posts: 1,600
Likes: 181
From: Durham ON
A sagging floor is usually caused by loose rivets where the bottom of the luggage stop panel is attached to the underbody, sometimes aggravated by a crack in the top of the tunnel. Permanent fix is to re-rivet the bottom of the panel to the floor, which may require drilling new holes; temporary fix is to put a hockey puck between the underbody and the top of the crossmember on both sides.