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I have had my 90 tc for about a year.The most anoying issue has been that the whole car seems to "jiggle" as I go over any imperfections in the road.

I have replaced the shocks,struts,cv axels and tires.I had a local shop inspect the bushings which they said were fine,thier opinion,Im not convinced. Im pretty sure I also replaced the strut mounts as well.I recently replaced the drivers door latch pin as I can hear the door squeaking against the weatherstrip.I thought the plastic bushing was worn but no change:confused: Do I have a bushing or motor mount issue?

Thanks,Mark

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You didn't mention what tire pressures you're running and if you're using the stock size or similar tire and wheel combination . Factory calls for 29# all around I believe.

These cars have a very short wheelbase so they will appear to have more "nervous" body motions than a larger car with a longer wheelbase. In addition, being a convertible, the chassis rigidity isn't the same as a closed sedan. You'll also notice some "cowl shake" when crossing closely spaced, short bumps like railroad tracks. This is normal due to the flexing of the chassis. Cowl shake is best described as a jiggling of the dash/windshield/ steering column areas as you're encountering bumps. This is commonplace to some degree or another in most convertibles. This is especially noticeable with the top down. Typically, it's noticeably less with the soft top up and even less noticeable with the hardtop in place.

When you think about it, the only thing holding the back and the front of the car together is the floorpan. The front mass and the rear mass are separated by the flexible floorpan and tend to resonate at different frequencies. The doors, when closed, help link the two sections of the car together but not as rigidly as the hardtop.

Unless you're using really low profile tires or higher than normal tire pressures, then I suspsect what you're experiencing is normal. If you can try riding in /driving someone else's TC for a comparison.

I suspect that "A", what you're experiencing is normal and "B", this is your first convertible.

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further the squeaking you are experiencing could very well be the rear quarter window weather stripping interacting with the door window weather stripping (mine does). The cure is to tap the quarter window down button.

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Mark, In addition to the above, I have found that my TC creakes a little on uneven pavement. This, in my case is caused by leather on leather rubbing together. It could be the pillows made into the seats, the seats rubbing against the arm rest or you bely and clothes rubbing against the seat. I have applied conditioners which subdue the effects somewhat, for a short time. This may be partially your problem as well.

Bob

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Great information. Over the years, I've owned several convertibles; the first one being a '48 Studebaker. The all had some of the shakes mentioned even with a frame under them. My wife had a LeBaron and now has a Sebring convertible and they have the shake and jiggle. It is definitely more pronounced when the top is down. My TC does it too! It's part of a convertible.

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Thanks for all your responses! To answer your questions,I am running stock wheels with bridgestone potenza tires at 32 lbs.I have the hard top on and tightened all the way at the hold down hooks and I can feel the top move so I suspect I will need to add some high density foam weatherstrip to the leading edge.

I understand the convertible/rigidity issue and this may be the case which doesnt make me any happier.The only other convertable I have driven was an '86 mercedes 500 sl with hard top on and no jiggle issues but then the tc "aint no mercedes sir":rolleyes: So your half right on my lack of convertibe experiece.

Do you think silicone spray will help the squeaky weatherstrip? As far as the leather rubbing,I changed my seats to audi tt leather sport seats which are narrower and more rigidly constructed so no leather or big belly issues here Bob:D

My new question is: is there a front strut brace that fits the tc and who out there has installed the rear sway bar that that "mopar guy" sells and do you feel a difference and where the hell does it bolt on?? Alan,Duane,Bob,Lou...anyone?

Thanks for the help guys as always.

Mark

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Sorry Mark, that was a mis-spelling. It should have read belT! However your point is valid!

WRT the silicone spray, I make it a point to spray all weatherstripping with silicone twice a year. That's just to make sure they will not belly out!!!

Bob

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I have had my 90 tc for about a year.The most anoying issue has been that the whole car seems to "jiggle" as I go over any imperfections in the road.

I have replaced the shocks,struts,cv axels and tires.I had a local shop inspect the bushings which they said were fine,thier opinion,Im not convinced. Im pretty sure I also replaced the strut mounts as well.I recently replaced the drivers door latch pin as I can hear the door squeaking against the weatherstrip.I thought the plastic bushing was worn but no change:confused: Do I have a bushing or motor mount issue?

Thanks,Mark

Excessive movement of the motor does cause a weird shudder over bumps and accel/deccel. Have you changed any (or all) of the mounts? I like a polybushings.com front mount in there and a good stock trans and passenger side mount. PB.com makes all the mounts and they will likely be the last ones you would ever buy for the car but the engine vibes are just a little to pronounced with three stiff mounts IMO:o

In my experience, the rear suspension needs the most help. Good stock struts (and mounts) up front do a nice job but out back I like to:

Change to 89 Shelby Daytona springs (1/2 coil cut) they have a stronger, larger wire diameter and take away the floaty feel. Also a PB.com rear swaybar (for a Lebaron) bolted in helps even more. PolyBushings has just started making adjustable panhard bars (which I haven't installed yet, I have one from another vendor in the worlds fastest TC. It locates the rear axle much more effectively than stock but is a bit clunky due to the heim joints used. PB.com units use rubber bushings that will solve the clunk. As mentioned correctly lubed/sdjusted rear bearings are a must as well. Also, I'm betting your tires are 44PSI rated, 32 is a bit old school 9and low IMO) I run 42 up front and 38 in the back tires. My TC's have LESS cowl shake then my Bro's '04 SVT Mustang Cobra 'Vert so they are not that 'noodley' as far as roadsters go....

Alan

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Hey Alan,it's about time you chimed in :) when I get time i'll check the rear bearings as barelyfit suggests,just not that motivated to work out in the arizona sun when its 105 degrees in the shade.

I have not changed any motor/tranny mounts yet and you are correct that the max tire pressure is 44 so i'll give it a try.I have been wanting to source the daytona springs and do the rear sway bar but I have allocated my limited funds to enhancing and upgrading my tc's interior and keeping my 95 bmw 540i daily driver on the road! Anyway it sounds like I've got my winter project to think about,along with timing belt,waterpump and front cam seal.....

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Hey Alan,can you explain why you feel that the recomended or slightly higher tire pressure is old school and the benefit of 42 psi in the front? I can see where the fronts may not wear as fast given the nature of front wheel drive.

Thanks,Mark

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LOW pressure is old school ande most tires stores are still living in it. Ever notice that when you get some new 44PSI rated tires mounted, the car will roll out of the store with 36PSI in them? Higher pressure = less rolling resistance, better milage, higher lateral sidewall stiffness to name a few. Only downside is a stiffer ride which is no issue at all on a TC. Now my wifes Crossfire SRT6 will beat you sensless with 44PSI in those little rubber band sidewall tires:o

Alan

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My understanding has been the pressure listed on the tire is the max psi to put in. The car manufacturer determines the proper pressure for the vehicle, weight, and the way the suspension is tuned, and the type of tire. If you continually deviate much from this recommendation you end up with uneven tire wear. to much psi and the tires wear in the middle, to little psi and and you wear the outer edges. Just my opinion.

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Jeff, I have to agree with you. Old school, or not, proper tire pressure is determined by the manufacturer to achieve best tire wear under normal driving conditions and the manufacturer suspension specs. There are certain conditions when one would increase or decrease the pressure, but I would not think that normal driving conditions would be one of them.

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I would have to agree with both of you, if you were right that is:p Would you guys agree that _________ have changed in the last 20 years (insert *any* manufactured product in that blank space) Sure, maybe an automotive manufacturer that rolls out a CURRENT car on CURRENT tire technology knows 'what is best' for handling and milage on their car. I've run as high as 50PSI cold pressure in modern tires and have never had the tire body deform enough to wear out the center like they did in tires of old. At the track I do vary front and rear pressures quite a bit but that is based on tire temp (inside,middle,shoulder) and what I'm trying to make the car do. It's hard to dial oversteer into a FWD car, I'll even run a softer/stickier tire in the front and a harder street compund in the rear... Next race is August 15th at Auto Club Speedway in Fontana. Feel free to come on out and watch me 'use up' some tires:cool:

Alan

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The thing is Alan, is that we are right. A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain under normal driving circumstances. However the tire's maximum inflation pressure should only be used when called for on the vehicle's tire placard or in the vehicle's owners manual.

I am not a tire design engineer nor an automotive design engineer consequently, if the manufacturer gives me an inflation pressure I, and most other people, will follow it. I would not want to be the person, following an accident, who tries to explain to the police and insurance company why I over-inflated my tires by 15 PSI because I know better than the experts in their fields. Safety should be a prime concern for all drivers.

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Umkay head in the sand, whatever you wanna think:p

Alan

So when you heaven forbid, have an accident in your TC, you're insurance asks you how much air is in the tires?? Or did Lee Iaccoca ask you, or Alejandro De Temaso:rolleyes:

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I would suspect that higher tire pressures would only make the jiggling worse by passing more road shock up into the body. Isn't the factory recommended pressure 29 lbs ?

Are the door hinges in good shape, with little up/down play at the back of the door when the door's open at a 45 degree angle to the body ? The doors really tie the front and back of the car together, especially if the top's down.

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