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65 365hp coupe
so when I have a passenger in the car, when I accelerate I hear a rattle/vibration coming from behind the seats. Only when there’s a passenger. Initially I thought it was the exhaust, was much worse with the rear exit but now has side exhaust. Thinking maybe the crossmember bushings. I’ve looked under the car and can’t see any areas when something is rubbing.
Check the distance from your exhaust crossmember to the floor. It should clear (from the factory) by 3/4" of an inch. If the floor panel is sagging, your drive shaft / ujoint is rubbing the floor panel when you have a passenger in the car.
Also, check your Cargo Stop panel behind the seat......its most likely loose and needs looked at!
If I'm guessing correctly, the floor panel needs to be raised with two 5/8"-3/4"! Hard Rubber blocks 2" x 3" laid on top of the Exhaust cross member on either side of each exhaust port on top of the cross member...
Check the snubber bushing on the differential mount. If it is poly or compressed due to age. This may cause the driveshaft to hit the tunnel. I would also inspect the cargo stop behind the seats. Over time, it cans sag. Jerry
Check the snubber bushing on the differential mount. If it is poly or compressed due to age. This may cause the driveshaft to hit the tunnel. I would also inspect the cargo stop behind the seats. Over time, it cans sag. Jerry
thank you! I’m unfamiliar with the cargo stop, is that the carpeted cover over where the jack goes? Great suggestions
The drive-shaft U-joint at the front of the rear end is rubbing on the tunnel due to "age sag" when the car goes "squat" and the weight of the passenger just makes it worse. Put it on a lift and you'll find the "witness marks" on the tunnel.
You will need to replace the rubber spacer at the front bolt of the rear end. I replaced mine with an aluminum rear suspension locating kit from Guldstrand.
The luggage stop is carpeted. Peal the carpet back, you should see the rivets securing the panel to the fiberglass bulkhead. If any or all are missing or lose, re-rivet the panel. Dennis
The luggage stop is carpeted. Peal the carpet back, you should see the rivets securing the panel to the fiberglass bulkhead. If any or all are missing or lose, re-rivet the panel. Dennis
ah! The horizontal panel behind the seats, got it!
Better check the floor sag!!! it will affect both any under seat noise and the pinion end of the driveshaft noise (behind the seat) By raising the height over the Exhaust cross member to 3/4", that will in turn raise the floor panel at the pinion end of the drive shaft by a least 1/8" or more!!
If you going to work on the Cargo stop, check and raise the floor, if needed, first......
65 365hp coupe
so when I have a passenger in the car, when I accelerate I hear a rattle/vibration coming from behind the seats. Only when there’s a passenger. Initially I thought it was the exhaust, was much worse with the rear exit but now has side exhaust. Thinking maybe the crossmember bushings. I’ve looked under the car and can’t see any areas when something is rubbing.
Keep those pesky passengers out of your car and problem solved😀!
Better check the floor sag!!! it will affect both any under seat noise and the pinion end of the driveshaft noise (behind the seat) By raising the height over the Exhaust cross member to 3/4", that will in turn raise the floor panel at the pinion end of the drive shaft by a least 1/8" or more!!
If you going to work on the Cargo stop, check and raise the floor, if needed, first......
Before you put the car in the air to check what Dan is telling you, go visit your local sporting goods store and buy two hockey pucks (seriously). When you raise the floor of the car using a floor jack and a piece of 2x4 (next to the crossmember) you can slide a hockey puck on either side of the transmission tunnel between the crossmember and the floor. Two per side may even be better.
Better check the floor sag!!! it will affect both any under seat noise and the pinion end of the driveshaft noise (behind the seat) By raising the height over the Exhaust cross member to 3/4", that will in turn raise the floor panel at the pinion end of the drive shaft by a least 1/8" or more!!
If you going to work on the Cargo stop, check and raise the floor, if needed, first......
Will most certainly look into that, I'm curious how the floor can sag when it's fiberglass? I"m familiar with metal creep but not polyester/fiberglass. The luggage stop is loose, don't know how you could have one of these cars without the forum.
Will most certainly look into that, I'm curious how the floor can sag when it's fiberglass? I"m familiar with metal creep but not polyester/fiberglass. The luggage stop is loose, don't know how you could have one of these cars without the forum.
there is no brace on the floor pan to help support. The luggage stop helps keep the floor where it belongs. These cars have a luggage capacity of around 500 pounds for a good reason. But to fix the rivets correctly is a whole lot of work and very hard to do with the body on the frame.
Yes, and the transmission tunnel molded into the floor pan acts as a natural weak-hinge point to fold up (or in this case, down) in the center. Front to rear the tunnel helps rigidity. Side to side - not so much.
mine had a noise (and vibration that could be felt) that sounded like it was coming from the console, but only a passenger was along. I took the seat out and found that the seat adjustment locks were only working on one side. the spring on the non-handle side was missing and the lock was not making contact with the track. added a spring and the seat locks on both sides now. I haven't tried it out yet, but it pretty much looks like that was the problem.
if you raise the floor exactly like Leif had explained in his post, you might find that all of a sudden, your cargo stop will tighten up a bid. Maybe enough to pass of replacing some of those pesky rivets.... Those properly placed pucks will help support the floor and the Cargo stop, itself.
Check your rear deck emblem and make sure it is not vibrating. Mine did years ago, and helped another forum member out with the same problem. I don't know whether a passenger would cause it though.
So was under the car this weekend and it did look like the floor had "hinged" a bit, about 1/4" clearance in the center, 1/2 near the doors. I wedged some door shims in to see if the noise went away, can't really tell yet. Need one of my fatty fatty fat *** buddies to ride with me, my 120# wife isn't burly enough to make the noise happen. I like the hockey puck suggestion, I'll give that a try on the weekend. Didn't see any area where rubbing occurred.
Obviously go slow, any tips on how to jack the floor up without causing even more drama in the form of broken fiberglass?
[QUOTE=texasC2;1607566315]So was under the car this weekend and it did look like the floor had "hinged" a bit, about 1/4" clearance in the center, 1/2 near the doors. I wedged some door shims in to see if the noise went away, can't really tell yet. Need one of my fatty fatty fat *** buddies to ride with me, my 120# wife isn't burly enough to make the noise happen. I like the hockey puck suggestion, I'll give that a try on the weekend. Didn't see any area where rubbing occurred.
Obviously go slow, any tips on how to jack the floor up without causing even more drama in the form of broken fiberglass?[/QUOTE]
Re-read post #10.
1) Place a floor jack under the rear RIGHT corner of the left seat section of the floor recess panel.
2) Jack, carefully that section a bid at a time checking the increase in gap. DON'T over do it!!!!
3) Put a dab of dielectric grease on the hard rubber 3/4" 2" x 3" (or puck) spacer (both sides).
4) Once the spacer is started, tap the spacer in with a hammer from the rear to the front between the floor panel and the cross member. Slowly release the jack.
5) Repeat on the RIGHT side, knowing that the entire procedure will be much easier because you have already raised and blocked the panel on the LEFT side.
Go to post #6 of this thread for pictures and associated discription:
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Help with rattle
Dennis
By raising the height over the Exhaust cross member to 3/4", that will in turn raise the floor panel at the pinion end of the drive shaft by a least 1/8" or more!!
