car shakes above 60mph [Archive] - Chevelle Tech

: car shakes above 60mph


Justin Mciver
Jul 12th, 99, 9:44 PM
ok now Ive had this problem for a long time.
so far ive rebuilt the front end, got new tires and had all the u joints and front end checked by a profesional. my car still shakes on the freeway.
is the only thing left the drive shaft?
it looks like the drive shaft had bottomed out on the hump in the floor. would that bend it or something? I cant see any missing weights.
thanx for you help.
Justin

Canuck64ss
Jul 13th, 99, 3:18 AM
If you suspect the shaft, find a place that will build a driveshaft and take yours there. They can balance it and it won't cost much. It's 40.00 canadian. I had my driveshaft made at a Heavy Truck center and it only took a few hours.

Have you checked the motor mounts, trans mount etc... A broken mount can cause a whole lot of trouble.

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The proud owner of a Canadian 64-SS with ZZ4 Power!
Team Chevelle Gold Member #37
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Brian Termine
Jul 13th, 99, 9:23 AM
Do you have aftermarket wheels with drum brakes up front?

I seen aftermarket wheels interfer with the drum balancing weights and it created a similar situation at higher speeds.

Brian

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rgribi
Jul 13th, 99, 11:29 AM
Also check how the u-joint fits into the rear yoke. If you're using straps to hold the driveshaft on, they can stretch over the years and allow the u-joint to wear away the little lips on the outside of the saddle.

Here's what you do: Place the rear of the car on jack stands. Remove the u-joint straps and see if the u-joint slides side-to-side in the saddle. If so, it will cause an imbalance at speed. To correct the problem you'll have to replace the pinion yoke.

How do I know? I had the same thing. At any speed above 60 mph, I had a terrible vibration that made the rear view mirror useless.

[This message has been edited by rgribi (edited 07-13-99).]

[This message has been edited by rgribi (edited 07-13-99).]

Justin Mciver
Jul 13th, 99, 2:00 PM
Ive had the U joints checked by a mechanic and he said they are fine. the rims ive had for a long time and it has not always done it with them. I have a cowl hood and can see the air cleaner from inside the car. the motor does not appear to me shaking or moving.
thanx for all of your help.
Justin

JWagner
Jul 13th, 99, 2:47 PM
Went through this last week. I replaced the rear bushing in the trans because the driveshaft yoke wobbled in it and I was sure that it would fix it. Got the car back together and the vibration was less, but still there. Traded driveshafts with another car in the driveway and now have no vibration. The offending shaft was probably bad from day one.It had multiple layers of balance weights welded on it and it looked like a factory job.

ferrill
Jul 13th, 99, 4:35 PM
If your car is automatic make sure the tail shaft bushing in the trans is good . I had one that was bad and it drove me nuts for months.

Justin Mciver
Jul 13th, 99, 7:17 PM
how do I check the yoke?
thanx
im gonna try to find a place to take the drive shaft to.

Canuck64ss
Jul 15th, 99, 3:25 AM
Justin,

I have been chasing a similar problem in my 64... Thought that I had it when the driveshaft was re-balanced, it did make a difference but still had the shakes. Finally took it to a friend who builds & restores High End Vette's. He played with it for a day and found the header just barely touching the A-Arm. When the motor hit certain rev's it would knock the A Arm just enough to throw vibrations through the whole car.

Solution: Using a come-along from the underside, pulled the motor over a touch and ground off a bit of the a-arm flange. Released the come-along and after a 1/4 Inch of space was available between the Header & A-Arm the are no more "Bad Vibes" coming from there.

Hope it helps

Justin Mciver
Jul 15th, 99, 9:02 PM
problem solved, I finally broke down and took it to the best place in town. I have crager SS rims and the lugnuts require a special lop-sidded washer. I guess the tire shop put them on wrong and ruined them. so 20 new washers installed correctly and on the car wheel ballencing solved all my problems. doesnt make much sense to me but im happy now doing 100+mph

Doc Willis
Jul 16th, 99, 7:47 AM
Thanks for the info, guys. My son's '71 nova has the same shaking problems at 65+ mph. I'll use your advice to see what I can come up with (though at this time, the shaking certainly dissuades him from wanting to drive too fast).

[This message has been edited by Doc Willis (edited 07-16-99).]