blackiosh

I bought a 1969 Mustang several months ago and am having issues with the front end and steering wheel shaking/bouncing at speeds of 65-75 mph.

Here is the info on the car: Former owner placed a 5.0 V-8 from I believe a 1994 Mustang. 5 Speed manual transmission. An alignment shop checked the front end suspension and steering and no issues found. Drive shaft was recently balanced, and new wheels and tires are balanced.

Car does fine until about 65 mph when the steering wheel begins to bounce. The front end acts like the wheels are out of balance. The hood shakes side to side also at highway speeds. The bouncing stops the instant I let off the gas and the car rides very smooth until I hit the gas again. It also seems to subside a little bit the faster I drive. I don't have a tachometer, so I can't say at what RPMs the shaking is occuring. Also, the speedometer needle bounces a ton at highway speeds so my MPH is an estimate.

That is about all I can think of. I would appreciate any suggestions. I know very little about cars and some of the shops I have taken the car to don't seem too interested in figuring out the problem.

Thanks

Firstgothenshow

I always try the zero cost approach first such as, rotate the tires and see if the shakes / vibrations are reduced or eliminated but while the front wheels are off, look at both side of the rims to see if you can find a spot that looks like a wheel weight decide to depart the vehicle. Don't laugh but once I lost a drive shaft balance weight and the entire vehicle shook like I was driving on railroad tracks. Again look at the drive shaft to see if one of the welded weights flew off and while your down there check out those universal joints very closely with a bright light. You can chock the vehicle wheels front & back, put the trans in neutral and twist the drive shaft clockwise and counter-clockwise to ensure there is virtually zero slop. If all is well I would then move on to front end shocks and look for shock seal leaks or other obvious issues like anti-sway bar / link kit bushings missing in action. This should keep you busy on Turkey day, have fun and let us all know what you find.

fastbackford351

Back in college I had that happen before in my 68 Firebird exactly as you described.
My shock absorbers were shot. New shocks solved the problem.

Stepman

This seems to be a mount issue to me. I was thinking shocks, but, not sure if it would make a difference being on or off the gas.? U-joints act up at 35 and quit vibrating at 40....You had the driveshaft and front end checked so, I have to think it's not a balance prolem but, maybe an alignment issue. How are the engine and tranny mounts?

musnicki

What kind of tires are you running? Bias Ply or Bias Radial? You'll want Bias Radial, they are more durable and balance better. You may have already covered the tire issue...they could just be old as well. Just trying to help you out. I've been lurking on this thread to see what the issue is and I see that it's still not resolved.

I'm finding that when I go to the part store people sell me stuff thinking that I have a trailer queen as opposed to a car that I have put over 40k miles on the past 6 years, it happened when I bought tires a few years back and rims. I could never get a good balance on my rims...

James

fastbackford351

It did make a difference on my Firebird whether or not I was on the gas. At speed it shook like a puppy pooping peach pits when I was on the gas and as soon as I let off it smoothed out but if the alignment shop checked the front suspension then they certainly should have verified that your shocks are good.

But yeah, if they are new wheels and tires they might be sub par and not be able to get a good balance job on them. A friend bought a set of cheapy import Magnum 500 style rims and they wouldn't balance for crap.

blackiosh

James,

I am running the BFG Radial TAs on the Mustang. They are brand new as well as the wheels. The drivesaft, U-joints and front end all checked out (according to the alignment shop). I have brand new shocks as well.

Stepman posted that he thinks it might be an engine or tranny mount issue. I will check that out.

Thanks for the help.