Shaky C4 Vert.
Thread Starter
Instructor
Joined: Feb 2005
Posts: 160
Likes: 0
From: Tampa Fl
St. Jude Donor '06
Shaky C4 Vert.
I wanted some opinions from fellow vette convertible owners. I own a triple black 95 vert, automatic. I have bad shaking at 55 to 60 mph. I have new tires, new rear hub and bearing assemblies which reduced the vibration. Have had tires balanced many times. Have cross bar from RD sports, and still at times, heavy vibration. I have been told this is common in C4's and I know they cannot compare to the ride of a C5. But, how can so many C4 owners live with this.
Any thoughts, or is this just reality, or did I buy a poor C4.
Thanks!!
Any thoughts, or is this just reality, or did I buy a poor C4.
Thanks!!
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I would make damned sure the x-brace is tight.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
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Joined: Dec 1999
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From: Almost all Skyline Cruises Vettes at Waterside 1-5
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Originally Posted by bogus
I would make damned sure the x-brace is tight.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
My 88 C4 roadester is tight, with the top up or down!Check the x braces...There is also a pair of braces that runs from near the firewall (they bolt to the hood sockets)
Sorry you are having difficulty
seeya
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
My 92 roadster was solid as a rock at any speed and even more so once the hardtop was installed. In the 8 years I owned it, it always gave a smooth ride from 25MPH to approaching 160. 
I would guess that the tires you have may suffer from flat-spotting. If the car sits for a few days after a long drive, the hot tires will take a "set" where the tire contacts the garage floor or pavement. This contact area will take some time to heat up and allow the tire to (in effect) become round again.
You may also want to check the tires for an out-of-round condition. Any good tire shop can do this and the tire can be trued on a sort of milling machine. Also have the wheels checked for any runout and check the mounting flange of each axle hub and the wheel mounting flange for any material that may keep the wheel from fitting flush. Check the lugs for proper torque (90-95 ft-lbs) and torque the lugs in a star pattern.
What you are describing is not normal and you should see a smooth ride. Another possibility is a bad u-joint in the half-shafts. Or, if they were not replaced at the time the rear hubs were done, they could be installed improperly. The shop should have marked the position of the half-shaft on the axle flange so it would be re-installed in the same position.
I would guess that the tires you have may suffer from flat-spotting. If the car sits for a few days after a long drive, the hot tires will take a "set" where the tire contacts the garage floor or pavement. This contact area will take some time to heat up and allow the tire to (in effect) become round again.
You may also want to check the tires for an out-of-round condition. Any good tire shop can do this and the tire can be trued on a sort of milling machine. Also have the wheels checked for any runout and check the mounting flange of each axle hub and the wheel mounting flange for any material that may keep the wheel from fitting flush. Check the lugs for proper torque (90-95 ft-lbs) and torque the lugs in a star pattern.
What you are describing is not normal and you should see a smooth ride. Another possibility is a bad u-joint in the half-shafts. Or, if they were not replaced at the time the rear hubs were done, they could be installed improperly. The shop should have marked the position of the half-shaft on the axle flange so it would be re-installed in the same position.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Originally Posted by bogus
I would make damned sure the x-brace is tight.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
The C4 is not the strongest platform for convertables... but they are not that bad. I drove a 92 roadster recently, and found the car to be tighter then my coupe with the top out.
Mines pretty tight and I don't get much cowl shake unless I am beating on it pretty hard.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Well for something totally different when I got my car it had a shudder in that range that was just plain scary.After a tranny flush it got somewhat better.I just replaced the tranny and TC and it is gone now.After getting some more info I believe it was being caused by the torque converter.Don't know if that is your problem or if it is suspension but it took me some time to figure it out and 2 tranny guys told me it was the engine.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Vibration like that isn't going to have anything to do with the X-brace. Absence of the brace would probably reduce vibrations because the car is all floppy without it.
Vibration in a speed range like that is almost always something to do with the wheels, tires, or bearings.
Did you get the wheels balanced on a Hunter machine?
They don't. This is not a "C4 problem."
Vibration in a speed range like that is almost always something to do with the wheels, tires, or bearings.
Did you get the wheels balanced on a Hunter machine?
how can so many C4 owners live with this.
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