front suspension wobble

[topless82vette]

I have a problem which seems to be coming from my left front wheel, when I start to accelerate the car has a strange wobble in the front end, it started after converting the car to a convertible also had my neighbor do some welding on the front frame crossmember while he was doing it he said he smelt rubber burning .... from what I have heard from other vette owners that converted theres their cars have had no side affects like this so Im wondering if there is a strong possibility that this rubber smell was infact one of the a-arm bushings being incinerated and what is a easy way to tell if this is what it was .... prior to all this work car never did anything like this whatsoever, so Im hoping one of you can shed some light on what possibly might be wrong

 

[RalleyRed]

Topless,

Have you had it up on a lift for a look, sure sounds to me that something melted.
What was the welding for and exactly where was he welding and why.

I wouldn't drive very fast to the shop, but get there quickly.


Rick

 

[topless82vette]

the welding was done on the front frame crossmember ( in front of the crankshaft pulley) added a serpentine drive system and he did some crossmember atlerrations so the pulley would clear, I also forgot to ad this wobble makes the car itself shake almost as though it has loose wheel lugnuts dont know if you have had that happen to you, also would a loose sway bar cause this, because I jsut remembered that I had forgot to really tighten the sway bar mount bolts that go to the frame ... no i havent had the oppurtunity to have the car on a hoist, and possibly could the car be suffering from flat spots on the tires as it has seen maybe 5 miles in the last 2 years, I see no dry rot on them and prior to car being worked on they were brand new

thaNKS

 

[sharky]

Hey topless. You can check the a-arm bushing`s by visual inspection, You should be able to see if they are gone. Just redid the whole front end on my 68` Not very tough. But i also had ac/oxy kit. Hope this helps . good luck to ya. Sharky.

 

[topless82vette]

sharky do you have aol instant meesenger ?

 

[topless82vette]

had to bring this one back to life .... today when I was running the car I decided to power brake the car a little and noticed that the drivers side of the motor rose about 8 inches and Im just curious if a broken motor mount will cause this wobble also when I let off the accelerator quik it felt like something in the rear end was shifting, I have looked at bushings in a-arm and tightened wheel bearings and felt tires for any movement but nothing has cure this problem, although my a-arm bushing are worn I have a 87 dodge that are much worse so I cant imagine these could be causing this problem, so what do you all think could this excessive motor mount movement be the cause of the wobble, I didnt have anyone to power brake while I watched but I would think if the motor rose much more than a inch you have problems in the motor mounts also what is involved in changing these ( this wobbling is felt through the steering and the body on the car shakes its that bad it really noticeable when you initially accelerate and put your foot into it)

thanks for your opinion

 

[78SilvAnniv]

not much experience...

(I have had a broken motor mount)

...but I have an opinion.
I don't think a broken motor mount would cause your vette to shake like you were describing. Under load, it should only lift up on the driver's side and settle when you let off. I can't see that causing the shaking you were experiencing. (unless it was bouncing around in there, but with steady rpm's, I don't see that happening)
I think the bushing getting welded is a good place to start looking. The movement in the back?..when did you last check the trailing arms and side yokes?
Heidi

 

[topless82vette]

silver

at steady rpm's or easy take offs it has just a real small shake to it but when its tromped on basically the front end of the car shakes real bad I just had the car up on jack stands (all for corners and while idling in gear) i do notice alot of vibration from the tires as well as rattling noises but I have never heard anything like this while driving it so Im not sure if thats just caused by the weight being off the tires, prior to being converted into a convertible the car always drove nice no shakes no vibrations at all, it has had maybe 4 miles put on it since all the converting was done thats why Im skeptical that I have a trailing arm problem since it didnt before, I have new motor mounts and trans mount coming for it today so with any luck at all Im hoping that will fix the problem if it doesnt then probably will send the whole rear suspensin out for rebuilding and forget about my kid going to college LOL

 

[topless82vette]

silver

also when the motor was misfiring this shake was noticably worse, also tires have absolutly no signs of wear problems front or rear and they have approx. 10 thousand miles on them so Im guessing alignment isnt a issue either

 

[gb4622]

Hey topless, was out cruising the forums and came across another thread (rear bearing questions) where you mentioned putting the car on jack stands and lots of strange noises and vibrations coming from the rear.

Not trying to be a pest, just trying to keep you from doing something bad to your car which in this case can happen rather easily... here is a snippet of what I wrote under the other thread...

+++++

The rear of our cars are designed to run with the wheels on the ground to horizontally align the differential with the rear wheel bearings. (This kinda keeps everthing in a straight line as viewed from the rear of the car... does this make sense?)

You can do real damage if you operate the car with the rear wheels hanging. This puts a ton of stress on the differential, side yokes, u-joints, wheel bearings and spindles. All the manuals recommend against this.

Should you want to run the car with the wheels off the ground, at a minimum you should put jack stands under the trailing arms so that the drivetrain remains horizontal as would be if the wheels were on the ground. (But I wouldn't recommend this unless absolutly necessary.)

+++++

Now, for your front end wobble, you might try jacking up the front end and taking a peak at the underneath suspension parts. Sure does sound [and smell] like a bushing got toasted.

If you think it might be an engine mount, try booking down the road and put the car in neutral and see if the wobble is still there. My mounts were shot and I had engine vibrations, no wobbles (or maybe I should say my wobbles were caused by worn suspension parts verses the engine mounts.)

Lastly, as much as we want to redirect the funds from our childrens college money, it is best to send them off to school so that they can make the big bucks to support us in the fashion we want to be accustomed to. Its either that or hope [and pray] that they marry rich. My daughter is a junior in college, I am poor and feel your pain, unfortunately I will probably always be poor as my daughter thinks I am kidding when I tell her the above. LOL

Good luck and have fun...

 

[topless82vette]

qb

so this vibration with wheels off ground could be normal then ? also as for coasting in nuetral NO the car stops this shaking immediately it really doesn't seem like its associated with speed either as it starts doing it the second you try taking off

 

[sac001]

Topless, it sure sounds like the major problem is the motor mount, possibly being aggravated by the worn A-Arm bushings.

I would do a very thorough check of the motor mounts. No way is the motor supposed to move 8 inches in any direction. If the mounts are good, keep checking where the mounts bolt up for any frame damage where the mounts connect or nearby. I strongly think the mounts will be the major problem.

Once that is resolved, give it a gentle road test to see how the A-Arm bushings are holding up. Considering the amount of work done to the car in the transformation, be very cautious testing it until you are satisfied that everythin is as it should be.

Good luck and keep us posted.

Steve

 

[gb4622]

Hey topless...

After reading back thru the posts and based on your recent entry, I too think you have nailed it on the head as being engine based rather than suspension.

One light that went off on the second reading... you mentioned all this started when you added a serpentine belt...

Might you have a pulley or something related to this new belt system that is not quite balanced.

Maybe the engine mount was questionable for awhile and the sepentine belt just brought it to light. Just a thought.

Now ain't this fun...

Let us know what happens after you replace the motor mounts and good luck.

 

[topless82vette]

thanks everyone for your replies I just took the car for a real brief spin and after changing the drivers side engine mount ( it came out in two pieces) this really bad shaking appears to be gone I took and did a from standing full throttle take off enough to break the tires loose and absolutly no more shaking. tomorrow I'm going to install the passenger side one and a trans mount since this mount has probbaly caused alot of stress on the other ones, after that Im going to DMV on monday and registering the car, then after I have a little fun with it I'm going to order a complete front suspension rebuild kit as well as rear trailing arms and a complete bushing kit for the back.

after thats all done look out california cause the wife will have her baby back LOL and then Im going to look for a nice project vette to trade for my trans am and once again Im going to do yet another convertible conversion for me, can't let the wife have all the fun

 

[topless82vette]

gb

no all the pulleys look like they are running true Ive watched them at low & high speed and although they have a extremly slight shake which I think all pulleys do mine dont appear to even be a little problem, Im thinking also flat spots could be a little problem to since its had at the most 4 miles put on it in the last 2 years, the ride is harsh on bumps so my shocks have probably suffered from all the sitting ... also now that motor mount was changed engine doesnt shake a bit while its idling just nice and smooth

also I know crossfire motors were never power houses so why does mine seem so powerful block vin matches vehicle vin Im wondering if its had internal changes sometime in its life I had a 305 tpi iroc once and raced my wife and she just walked away from my iroc, this one cant really smoke its tires hard on take off but it can haze the tires without power braking gearing appears to be stock although who know it turns 1800rpm at around 70-80 so I kinda think it doesnt have performance gears

 

[gb4622]

Glad to hear the good word...

Now go drive the car and have some [real] fun before turning it [back ??] over to the wife. But that has its advantages also, cause we all know that a happy spouse makes for a happy us.

So you're gonna tackle the entire suspension... I just completed that task on my 73, front and rear. Its a bunch of work, but you're gonna love how it handles when you're done.

So, one more time... isn't this fun.

And as you work on the entire suspension just keep repeating that to yourself (trust me when I say there will be moments when you want to blow up your car) when you are done it is well worth the experience. Or so I keep telling myself... LOL

 

[topless82vette]

qb

I once did the rebuild on the front of my 84 trans am's suspension (of course machine shop pressthe bushings) but I went with new springs but retained the stock rubber bushings its a ws-6 car and ive always been happy with it's handling so I didnt see the need for urethane bushings, so I will probably do the vette the same since my wife prefers a softer ride I may upgrade the car to the monoleaf front suspension kit though Ive put to much money into the steering stuff so a rack and pinion setup is out of the question now, we had pondered with the idea of doin a frame off but its a street car and whats the use of doin that when its subjected to alot of elements