It was a sunny day and decided to get my new ANSA muffler installed. I store the car on three hyd. jacks with the tires about 6" off the ground. I pulled the car cover, dropped the car back onto the ground, discounted the battery maintainer and started it up to warm up. All seemed normal at 25 mph while driving out of the subdivision. I pulled onto the main street and when the car reached 35 mph it started to vibrate badly to the point I had thought I blown a tire. I pulled into a parking lot and to my surprise all the tires looked normal. I then checked each wheel to make sure it was not loose. All seemed normal so I decided to continue on my way and as I reached 35 again the vibration started again. I tired speeding up, putting the car in neutral, and steering side to side and nothing seemed to make it better or worse. I drove it about 5 miles and by the time I reached the muffler shop the vibration was all but gone. I drove the car home on the expressway with no problems and by the time I was home everything was back to normal. I spoke with Gary (vaulk) and the only thing we could come up with is maybe the weight of the rear end was placing a stress on the CV joints and caused this. My question is should I just leave it on the ground for storage. I'm also worried about the drive down to the dragon and having problems. I think it would be a waste of time and money having it looked at since the vibration is gone. Any suggestions would be much appreciated.

 

Hi Franc,

Well I'm not sure it has to do with the car being in the air. I store my car for the winter as well but I don't put it on jack stands. Last month we got heavy rain for two days () washed all the salt away!) and then it was nearly 65 degrees and sunny so I couldn't resist the urge. I started the car, warmed it up, drop'd the top, with wing up I went for a ride.

Exactly the same issue you have documented. About 35 to 40 MPH violent vibration. I pulled over in a church parking lot and inspected everything. No visible issues? Got back in about two miles down the road it smoothed out and there were no more vibrations for the next hundred miles?

I just thought it was possibly flat spots because I hadn't moved the car for several weeks. After hearing what happened to you now I'm not sure. Hopefully someone will have some idea of what is caused this?

This is my second Roadster and I stored the first one the same but never had this issue? I'm with you, anyone got an idea?


Respectfully,


Paul (MisterTaz)

 

I wonder if you had something accumulated on your wheels that caused an imbalance that finally fell off after a while driving?

 

Well that would suggest it's not the problem of it being jacked up. Wow this is weird, I hope others post. I've stored mine for three seasons and this is the first I have had this happen. Did it take about 5 miles of driving for it to smooth out?

 

FP,

Not a chance. The wheels were detailed when I put it up and I went over the whole car before I started it. Had to be something else...

Thanks for the thought but it has to be something different...


Respectfully,


Paul (MisterTaz)

 

I don't think so FP- It had a car cover on it and nothing goes in or out of the garage all winter. I have a separate garage for my crossfire.

 

Just wondering are you both using the same tire?

 

I had the stock Conti all seasons on for storage. I had flat spots with the Eagles in the past. But when that happened it felt like flat spots, this was violent shaking. I wasn't sure if something hadn't broken in the drive train. But after a few miles it went away???


Respectfully,


Paul (MisterTaz)

 

i was going to guess flat spots on the tires too.

 

Cold tires Frank, just get them heated up and you will be fine...its cold up there buddy...this happens even when jacked up...just get out on the road and take her up easy until they heat up...

 

I agree with the Doc , if CV joints could do that then your is deep whale do do, thats deep. Id buy cold tires in a moment, and see no reason to jack up a car unless it is parked for 5 years in which case the tires are suspect for cracks unless you deflate them. Woody

 

I see "reasons" to jack, their little furry and have long tails. We are not as cosmopolitan as Frank, our FX stays jacked up and covered in an old cold garage, along with bikes, snow blower, mower and all the other crap garages have. We put mice traps around the base of each jack stand and there have been a couple sprung with a dead body.
Frank your car seems OK now? Gary said a way remote idea is fluids settled, rough vibrations getting everything back and moving around correctly again...he said remote idea. He though the cold tire idea was much more likely. Hows the new mufflers??

 

Was the vibration felt more in the steering wheel or your butt? Knowing this will isolate the problem to front or rear. Radial tires don't tend to flat spot from sitting, but this used to be a common problem with Bias ply tires years ago. I would be suprised if radials would flat spot especially if the are in the air.

 

It's a long shot but ...
if there was a build up of light rust on the surface of the brake rotors except where the pads were in contact with the rotors while parked it may have been the grabbing of the pads on the rotors on and off the rusted surface as the wheels rotated and may have transferred a vibration through the car.
I had this similar situation occur on another car parked for several months but the vibration was only present when applying the brake and also eventually went away after a few miles of driving and cleaning away the surface rust

 

Well lets look at a few comments made- Valk I hit the brakes and there was no difference so I doubt it was a brake problem. I do not see how a tire hanging in the air could develop flat spots. As far as cold tires, why wouldn't a car sitting out over night at below zero temperatures have the same effects when driving the first few miles. I have the stock all weather conti's on mine. Rapp's (Gary) you might be on to something. I'm just confused on why most folks who store have not had this problem and why mine the first 2 seasons of storage had not had it.

 

There is no advantage to lifting the car for storage, modern tyres do not flatspot, but it is a good security measure if you also remove wheels!
If you do, the suspension will fully extend to the bump stops and no harm will be done to any components, allthough its worth checking to see if the rubber boots on the CV joints are not fully stretched as they may become deformed when the cars back on the ground which can cause them to split. It has been known for balance weights to come of wheels and tyres to become deformed which causes vibrations etc. Its very unusual for rotors to rust when storage is in a garage, but, brake calipers have been known to stick (seize up) thru lack of use. When preparing to go back on the road you should pump the brake pedal while you are warming it up, then make sure you can roll the car back and forth to make sure the barakes are free before driving.

Cheers Steve

 

Just going to hazard a guess here....

When you have the car raised far enough up that the tires are off the ground then something has to be limiting the movement of the suspension. I'm guessing that the bushings/ball joints/CV joints are taking the streess of the springs pushing down on them. You are also extending the shocks to the limits of their travel. Many of these items are meant to have an operating range that they stay in. Leaving them extended past this range for an extended amount of time will definitely cause problems.

I posted in another thread that if you are going to store your car on jackstands to the frame......it's very worthwhile to get 4 more jackstands and support the suspension a couple of inches from full bottom.

 

These were my thoughts to and I had started this other thread initially.

 

I would have said flat spots, our 1992 Vette got them on F1 when it sat for a few months. Max pressure and a sort drive to heat up the tires got them out. Now its sits on pads to stop flat spots.

Do you konw if there was any of the flat stop gel in the tires? if someone had put that in there it would have all settled in the bottom and could cause the problem.

 

Nope no gel in the tires I bought the car new. From the points brought up in this post I'm inclined to store it with the tires on the ground from now on. One thing I thought of is if it was possible the steel cord in the tire is sort of stiff from not being flexed for months and creates the vibration. It hard to describe the vibration but it scares the sh*t out of ya. The vibration seems to be none directional.