car is wobbling

[Mach1JB]

Guys i realy need you help on this one.

When i drive my mach at 60/70 mph the car starts to wobble. ( i hope i use the right word for it !? )

Its a whining noise an a feeling that the car shakes every 1 1/2 second.

It's the same feeling as when there is a loose wheel on the car.

I have new tires , shocks front and rear , new transmission mount.

Has this something to do with the rear end or motor mounts !??

Please advice me,

JB

 

[caspianwendell]

Does the steering wheel shimmy back and fourth? or does the whole car shake? does this happen on acceleration or deceleration? Have you checked the driveline, u joints etc.?

 

[hyena429]

Mite be rear end...could be out of balanced tire...Mite of lost a led weight...but the whining sound says it mite be a little more than that...and +1 to what caspian says....Check that drive line and see if its loose..See if the u joints clunk....and all that....I had a wheel bearing go out on me...But it did not make my car wooble...But it mite if the bearing is ready to drop your axel out...You could jack it up and see if your rear wheels are lose too. while you check the drive line and such.

 

[Steve73QMach1]

Hi JB,

I had a 73 Mach 1 years ago that did the same thing. Have you had the driveshaft off recently? If so, did you mark it for re-installation in the same orientation? I had replaced U joints on mine and just re-installed the driveshaft without regard as to its previous orientation. My car would shake at 65 MPH but not at 70 or above. It would also not shake below 65 MPH. Anyway, I removed the driveshaft and rotated it 180 degrees to start with. I took it out for a test drive and all shaking was gone and I never had another problem with it. If you haven't had your driveshaft off recently, maybe you lost a wheel balance weight?

 

[Mach1JB]

I drove the car an hour ago and listened very carefuly.

It's not a whining noise realy , it's more a vibrating noise.

This was the first time i drove it on the highway , till 60 mph i don't feel a thing.

above 60 mph the car starts to vibrate , when i accelarate it's gone for a few seconds till i hold it on a higher speed , then a second later it starts again.

I never took of the driveshaft , maybe the previous owner did for some reason !?

I realy think the vibration comes from the driveshaft so i will check the u joints first.

Thanks for the input sofar,

JB

 

[73StangCoupe]

JB,

I'm no expert here, but I did lose a drive shaft doing about 40 mph. It was definitely an "I have to change my underwear right now" moment. You may have a problem with the u joints or even the rear end. Check it out before you drive it. Let us know what you find out.

 

[Boss1Ray]

If you bought the tires locally, that shop might be willing to re-check the balance. If not the tires or wheels they can put it on the lift for a good inspection. You problem reminds me of a tire/wheel balancing issue I had with a 71 Ford pickup. Two leaded weights on the (inside of) wheel came loose. I thought it was everything but that.

What I'm trying to say is rule out the easy stuff first. Or maybe easy/cheap...

Ray

 

[72HCODE]

I would rule out the tires and have them rechecked for balance. Years ago I had some new tires that sat for a long time. When I drove it things were fine, then it felt like the car was bouncing.

The bouncing got worse and was taking the car to a alignment shop when the front right tire exploded. Towed car to shop, all 4 tires were defective and have thrown belts. The internal belts on the tires had deformed for sitting for a long time. When I drove the belts started to shift inside the tires and eventually failure occurred. Check the sidewalls of the tires for deformation or bubbles as well.

 

[Bill73Ragtop]

Make sure the drive shaft u-joint at the rear end is fully engaged into the cups. If not, pull it and check that the bearings were not damaged during your test drives (might be work a check anyway).

 

[Mach1JB]

finaly my parts arived a few weeks ago , i replaced the drive shaft u joints and the upper ball joints.

My car drives like a Cadillac now...

Now i have to take care for some overheating issues and i'm ready to go.

Thanks for the replys guys

JB

 

[Kit Sullivan]

Sounds like an out-of-balance driveshaft. Not too difficult to rememdy yourself, if you are game to do it.

1) Put car on frame lift (not wheel lift) high enough for you to stand underneath the car safely.

2) Have someone in car as it is lifted.

3) Start car and slowly accelerate to problem speed. (stay clear of moving parts!)

4) Holding a piece of chalk, VERY SLOWLY raise the tip of the chalk to the underside of the spinning driveshaft directly on the bottom (6:00 O'Clock). Do this about 3-4" behind front yoke and again about 3-4" in front of rear yoke.

5) When the chalk just BARELY TOUCHES the spinning driveshaft, do not apply any more upward pressure. The chalk will leave a small mark on the driveshaft.

6) Decelerate the engine and shut engine off.

7) Apply weight to driveshaft exactly OPPOSITE (12:O'Clock) the marks on each end.

This will solve 99% of all driveshaft balance issues. Cheap and simple.

8) Recheck as before.

9) If still slightly out of balance, apply half as much weight at 3 and 9 oclock poistion.

 

[marks73]

Sounds like an out-of-balance driveshaft. Not too difficult to rememdy yourself, if you are game to do it.

1) Put car on frame lift (not wheel lift) high enough for you to stand underneath the car safely.

2) Have someone in car as it is lifted.

3) Start car and slowly accelerate to problem speed. (stay clear of moving parts!)

4) Holding a piece of chalk, VERY SLOWLY raise the tip of the chalk to the underside of the spinning driveshaft directly on the bottom (6:00 O'Clock). Do this about 3-4" behind front yoke and again about 3-4" in front of rear yoke.

5) When the chalk just BARELY TOUCHES the spinning driveshaft, do not apply any more upward pressure. The chalk will leave a small mark on the driveshaft.

6) Decelerate the engine and shut engine off.

7) Apply weight to driveshaft exactly OPPOSITE (12:O'Clock) the marks on each end.

This will solve 99% of all driveshaft balance issues. Cheap and simple.

8) Recheck as before.

9) If still slightly out of balance, apply half as much weight at 3 and 9 oclock poistion.

Since you wouldn't know how much weight to apply. You could take the driveshaft out and have it checked for balance. (Much safer)Sure any large town has a place to do driveshafts.

 

[Kit Sullivan]

That is the original Ford-approved method to balance a driveshaft as per the original shop manual. Tbis is more accurate than having the shaft balancex off the car for it also takes into account the diff and tsilhousing reciprocating assembljes as well.

But...if you don't want to mess up your recent manicure, you might want to go see a real mechanic.

I forget sometimes that some people who drive an old car like this are intimidated by what is behind the sheetmetal...

 

[72HCODE]

well the OP fixed the issue at the end of page 1 turned out he needed new U joints.

so we can save the chalk for another project.

 

[Kit Sullivan]

Sorry about that, but I was only responding to your remarks where I too felt slighted: "If I was 19 years old again and did not have a wife or kids and had no reason to keep living..." What was the inference there?

No matter: I apologize so lets remain friends.

I too am an engineer, among other 'certs:

1) Certified Tribologist and Rheological Engineer since

2001, STLE

2) Member and contributing engineer since 2003, SAE

3) ASE certs:

a) Master Tech:cars (2001)

b) Master Tech: Trucks (2003)

c) CertifiedTech: Emergency/Rescue vehicles.

4) contributing engineerng consultant to:

1) ExxonMobil

2) Ashland

3) Kendall/ Phillips 66

5) contributing consultant to:

1) Two Guys Garage TV Show

2) Gearz TV Show

3) DIY:Cars TV Show

Like many here, I have spent many years and expended tremendous effort to acquire the knowledge and experience I have. I pass that along freely to anyone on this forum that may care to use it however they see fit.

Just like you, I rankle when someone makes light of a legitimate response I have made with an offhand and derogatory remark such as your initial "If I was still 19..." remark.

In the general scheme of things, none of this is too terribly important, so let's have a beer and forget it.

 

[CZ-75]

You two need to get a room

 

[Kit Sullivan]

Noooooo, it ain't like that!

 

[smokem]

Sorry about that, but I was only responding to your remarks where I too felt slighted: "If I was 19 years old again and did not have a wife or kids and had no reason to keep living..." What was the inference there?

No matter: I apologize so lets remain friends.

I too am an engineer, among other 'certs:

1) Certified Tribologist and Rheological Engineer since

2001, STLE

2) Member and contributing engineer since 2003, SAE

3) ASE certs:

a) Master Tech:cars (2001)

b) Master Tech: Trucks (2003)

c) CertifiedTech: Emergency/Rescue vehicles.

4) contributing engineerng consultant to:

1) ExxonMobil

2) Ashland

3) Kendall/ Phillips 66

5) contributing consultant to:

1) Two Guys Garage TV Show

2) Gearz TV Show

3) DIY:Cars TV Show

Like many here, I have spent many years and expended tremendous effort to acquire the knowledge and experience I have. I pass that along freely to anyone on this forum that may care to use it however they see fit.

Just like you, I rankle when someone makes light of a legitimate response I have made with an offhand and derogatory remark such as your initial "If I was still 19..." remark.

In the general scheme of things, none of this is too terribly important, so let's have a beer and forget it.

I'm going to ignore it - in the month you have been here, you have been in 2 or 3 fights already.

 

[marks73]

Safety is safety. We don't do things the way we did 40 years ago for good reason (injuries) and I would doubt Ford still uses that practice.