Speed vibration

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65CherryMonza
Posts: 51
Joined: Sat Jul 04, 2020 9:32 am

Speed vibration

Post by 65CherryMonza »

Guys anyone have experience with speed vibration...?

It seams like my drive shafts aren't balanced or something.
As soon as I go over 55 mph the hole car starts vibrating badly...
Where should I start to check what it could be?
Any suggestions are welcome.
Thanks guys

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Storm
Posts: 169
Joined: Sat Feb 29, 2020 9:54 pm

Re: Speed vibration

Post by Storm »

I had this happen when I was around 70mph.
I first had the tires balanced, it helped but it still shook. So I thought new tires as one of my tires couldn't balance due to fix-a-flat in it.

So before I went to order new tires I thought maybe something was loose in the engine bay, plus I wanted to paint my main shroud black in the spots the paint was gone. So I proceeded to remove everything in the way to get it out. Painted, let dry & reinstalled everything again.

So I then drove out to dinner & noticed the shaking was gone, just slight wheel vibration from the one tire!

Moral of the story is, check to see if anything was loose in the engine bay! I'm guessing my generator bracket hold down was loose & letting the generator move. Although you'd think the belt would pop off.

Good luck

Storm

Kyle Storm

1964 Corvair Monza/110hp/4 Speed
1961 Corvair Lakewood/80hp/3 Speed

-Kyle Storm

1964 Corvair Monza Coupe 110/4spd
1964 Corvair Monza 4 Door 110/Automatic A/C
1961 Corvair Lakewood 500 85/3spd (restoring)
1961 Corvair Greenbrier 110/4spd (sold)
joelsplace
Posts: 1950
Joined: Wed Oct 13, 2010 12:51 pm
Location: Northlake, TX

Re: Speed vibration

Post by joelsplace »

I would think for it to be a driveshaft that bad it would have to be bent or the u-joints aren't installed correctly.
157 Corvairs, 5 Ultravans and counting
Northlake, TX
66vairguy
Posts: 4531
Joined: Tue Dec 21, 2010 3:44 pm

Re: Speed vibration

Post by 66vairguy »

Check the rear U-joints and wheel bearings. Sometimes PG cars have a torque converter issue, but usually that shows up at a certain RPM vs. MPH.

BTW - Nearly all the "over 55 MPH" vibration issues I've had were caused by a bad tire. How old are your tires? Did the car sit a long time on the tires?
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65CherryMonza
Posts: 51
Joined: Sat Jul 04, 2020 9:32 am

Re: Speed vibration

Post by 65CherryMonza »

Tires is a good start I think as they are fairly old... Still in good shape but old.

Guess I start with that...

I think I will also check my engine mounts as I don't know how old they are.

Thanks for the advice guys ! [emoji106]
Storm wrote:I had this happen when I was around 70mph.
I first had the tires balanced, it helped but it still shook. So I thought new tires as one of my tires couldn't balance due to fix-a-flat in it.

So before I went to order new tires I thought maybe something was loose in the engine bay, plus I wanted to paint my main shroud black in the spots the paint was gone. So I proceeded to remove everything in the way to get it out. Painted, let dry & reinstalled everything again.

So I then drove out to dinner & noticed the shaking was gone, just slight wheel vibration from the one tire!

Moral of the story is, check to see if anything was loose in the engine bay! I'm guessing my generator bracket hold down was loose & letting the generator move. Although you'd think the belt would pop off.

Good luck

Storm

Kyle Storm

1964 Corvair Monza/110hp/4 Speed
1961 Corvair Lakewood/80hp/3 Speed
Sent from my SM-N975W using Corvair Forum mobile app

Wagon Master
Posts: 474
Joined: Thu Jul 28, 2011 6:36 pm

Re: Speed vibration

Post by Wagon Master »

As others have mentioned, be sure all 4 u-joints are properly setted in their yokes behind the small tabs.
erco
Posts: 1489
Joined: Wed Apr 29, 2020 8:45 pm

Re: Speed vibration

Post by erco »

Old post, I know.

Another possibility is that you lost a balance weight from your brake drum. They do shed occasionally. I am amazed how big the weights are on mine. Hard to believe that the stock drum could be that far out of balance. I could see losing one could cause some serious vibration.

From https://www.counterman.com/drum-brakes- ... t-goes-on/

2. The balance of the brake drum is very important. Just like a wheel that’s out of balance, a brake drum can cause severe vibration for the same reason. Most of them have weights welded on the outside when they’re balanced during production. These weights can interfere with some aftermarket wheels. If that’s the case, the drums will have to be balanced in a different manner. Don’t just grind away or break off the weight.
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