I have been having sizeable vibration at highway speeds of 60 and above. I just put new tires (balanced, etc) on thinking that would resolve the problem but still getting vibration. It seems to occur when I hit the gas but stops when I take my foot off the pedal. Do you think bad u-joints?:paranoid:

I have been having sizeable vibration at highway speeds of 60 and above. I just put new tires (balanced, etc) on thinking that would resolve the problem but still getting vibration. It seems to occur when I hit the gas but stops when I take my foot off the pedal. Do you think bad u-joints?:paranoid:

Yes, vibration this bad you might be able to wiggle the shaft and find the culprit.

You might also check the half-shafts for play. Are the ball joints, tie rod ends, wheel bearings, etc... ok?

I agree with Kenz240Z, I would go threw the whole front end of the car, wheel bearings being a big culprit that Ive found a lot of people neglect in theyre cars like bushings for suspension components.

Check over your front end.

Thanks, for the info and response!

Your car is a 1970? Move your rear diff back. I have had both 1970 and 1971 cars. Terrible higway vice. I did the service fix update of moving the rear end back and what a major improvement! Check your moustache bar (behind diff). If it is flat, your car was not updated. You will need a 1972 or later moustache bar and a 1972-78 r180 rear diff mounting insulator..............

Thanks, rzola, will check on that.

duffman - please let me know what you find out. I assume you'll ask Gary at Spanky's. I have the same problem with my 1970 - over about 60 MPH it gets a bit wobbly so my top speed where I feel safe is 65 to 70.

My first Z was a 1972 and I had that up to 120 with no problems.

Derek

You'll know if your ball joints have gone south When those are shot if you hit just the smallest bump in the road you'll hear the front end making a noticeable clunkity clunk sound. It will make you cringe

I agree with the above along with checking the condition of the driveshaft as well. I think it was richard1? that was just recently asking about a similar issue as you.

Best of luck.

Most assured a u-joint. Now the trick is which one Look for rust at the joints. One that bad will almost always have rust that's visable.

Sounds like you are well on the way to solving your problem, but I'd like to offer one more piece of advice... I had an incurable front end vibration for a long time. Replacing tyres, bushes and tie-rod ends helped a little, but the problem was completely cured by having the wheels balanced on the car. By doing this, the whole rotating mass (wheel tyre, hub, disk etc) is included in the balancing operation. After this relatively quick and cheap operation my Z is as smooth as silk. The only thing to remember is to replace the wheels in the same stud position if they're ever removed...

You don't find many shops around anymore that speed balance your tires ON the car. I had someone do that for me back in the late 70's and early 80's.