"Jiggling" fenders on my 68 300?

Early C Bodies - The Slab Side Years

  1. WissaMan

    WissaMan Member

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    I can't tell if it's just a trick of the eyes or not, but to me it seems that if I go over a rough road the front fenders jiggle. I can definitely see that hood vibrate in certain areas, but I'm assuming that's because the adhesive that was used to tack the outer skin to the underside has separated.

    If the front of the car is actually jiggling around, is there anything that can be done to reduce/eliminate that? Such as adding some bracing somewhere? I know lots of cars have bars that connect from the firewall to the top of the fender. Perhaps something like that?
     
  2. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Was Chrysler using tuning weights in the four corners of their verts in ‘68? @MOVE N UP
    My ‘64 has them and I believe they continued through ‘66 a least. My ‘71 Challenger does no though and I don’t know what they did to alleviate that by then. I remember an old friend of mine had a 69 Camaro convertible that had what they referred to as cocktail shakers in each corner to dampen the shake.
     
  3. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    You might also want to check the bolts in the inner fender wells, if they are loose, they can't supply the needed tension to keep the fenders from "jiggling".

    Dave
     
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  4. WissaMan

    WissaMan Member

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    Interesting, I never knew that about those dampeners but I'll do some reading up on them.

    And actually, the outer fender wells on this car are rusted through in several areas so perhaps that is a contributing factor. R&R those is the next thing on our todo list for this car so we'll see if that makes a difference.
     
  5. thrashingcows

    thrashingcows Senior Member

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    Also make sure the bolts holding the rad support are not loose. But the rusty inner fender might very well be your culprit if the mounting points have gone missing. ;)
     
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  6. mr. fix it

    mr. fix it Old Man with a Hat

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    I've always known this as cowl shake... A built feature of all convertibles.
     
  7. WissaMan

    WissaMan Member

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    Looks like Yamaha manufactures a "performance damper" (the name of which could be interpreted two ways lol)

    Performance Dampers - Yamaha, product, business | Yamaha Motor Co., Ltd.

    It'd be interesting to fit one of those across the front of the car somehow, but they are pretty darn expensive to buy just to experiment. It'd be interesting to rig something up with a small shock absorber. Maybe from some small vehicle like a minibike or moped.

    This 300 is the first big old convertible I ever drove or rode in actually so I have nothing to compare it to ... other than my wife's Toyota MR Spyder convertible which is as tight as a fly's butt, but is only 1/2 the weight and size of the Chrysler.
     
  8. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    That style damper is designed to go between the shock towers on a McPhearson style front suspension. I doubt it would help a C-Body much. All C-Body verts have some cowl shake, usually most noticeable along the top of the windshield frame, that comes with the territory. There is no rigid roof panel to stop it from happening. Chrysler added extra metal, lots of it, inside the rocker panels to stiffen up the frame. This in turn tends to transfer some resonance from the very rigid metal at the lower part of the car upwards towards the cowl and the windshield frame. Equipping these cars with modern radial tires has tended to make the problem worse as these tires are also more rigid. Beyond being sure that the tires are well balanced, the door strikers and wedges are properly adjusted and your hinge pins are tight, there is no good fix to the cowl shake.

    Dave
     
    Last edited: Nov 4, 2019
  9. MOVE N UP

    MOVE N UP Active Member FCBO Gold Member

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    None of the 5 68 convertibles that I have access to, have any “tuning weights” in the fenders. My guess to the problem WissaMan is experiencing, would be missing or loose fasteners!
     
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  10. WissaMan

    WissaMan Member

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    I can't say for sure if it's the cowl and windshield frame that are shaking but maybe it is. It's kind of hard to tell when you yourself are shaking a little bit too. Do the tuning weights that detmatt mentioned reduce that? Or are the late 60's verts "as good" as the earlier models despite not having them?
     
  11. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Here’s the ones on the rear corners of my ‘64 Imp. They’ve got away at least as much as a cast-iron exhaust manifold and may have been limited to the Imperials as they were the top of the food chain in the luxury line. I am not sure though if they continue them after 66.
    21265F3E-02E8-44CF-91BC-7C132CEAC6BE.jpeg
     
  12. WissaMan

    WissaMan Member

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    Wow that's some serious weight hanging there. Probably helped for winter traction too! Are they just bolted to the floor of the trunk? And where are the front ones located?

    If I would've seen them on a car w/o anyone explaining them to me I'd have been scratching my head
     
  13. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Yes they’re bolted on. I haven’t actually seen the ones in front yet as they seem to be tucked up out of site and I’ve only just started playing with this car.
     
  14. Ripinator

    Ripinator Senior Member

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    Stop playing and git to work!
     
  15. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    I wanted to at least make the ‘64 run this year and I’m playing in between coats of stain and clear.:rolleyes:
     
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  16. JC68vert300

    JC68vert300 Well-Known Member

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    I agree with others to check bolts and fasteners. You mentioned your front fenders are rusted, so that could be why the fenders are "jiggling". I drive my '68 300 convertible on the roads of NJ, which are like the surface on the moon, and I don't have any jiggling. So I am leaning towards a structural problem.