1984 vibrations over 65 on smooth road

[fred porter]

all four tires have under 10000 miles ,just had frount end checked and had tires rebalanced. there is play in the rear of car when i jacked it up the tires have a about half inch of play side to side and up and down. rubber in contorl arms or dog bones does not look that great. car has 50,000 miles on it. at first i thought it was wheel bearings but after removing wheels it seems more like suspension problem. it feels like back of car wants to come around under hard exceleration. would new shocks help any of this, these have 30000 miles on them. thanks guys

 

[Bill C]

FRED

PARK YOUR CAR!!!!!!!!! :eek If you have that much play in the rear wheel bearings your an accident waiting for a place to happen.. Get the obvious bad parts fixed first. That would be the wheel bearing assemblies.

They are a bearing assembly and should have little or NO play in any direction. They can not be adjusted, only replaced! Jack up the rear and have some wiggel the H&!! out of the wheel and make sure that it's not some other movable joint that is causing the excess play. If it points to the bearings, it is a job that is'nt too difficult. The bearing assemblies are about $100. each

After they are replaced and A L L of the other rear suspension componets are checked and pass the test, have a good alignment shop that is familar with Corvetts do a FOUR WHEEL alignment.

Good luck and keep us informed on what you find.

Bill C

 

[David-F]

If your car wants to change lanes when you give it gas or let off you probable have a bad rear tie rod assembly. What suspension do you have? Is it a Z51? Also if you have tomuch rear negitive camber you can get a vibration at highway speeds.

David Fulcher

 

[jsinga]

If you change wheel bearings and don't know how old the halfshaft u-joints are take a hard look at them for another $50 you can kill 2 birds with one stone.
U-joints will cause your high speed vibration.
JS

 

[Bill C]

Fred

So,,,,, what have you found out about your suspension?

Let us know.

Bill C

 

[boblx2a]

Vibrations, etc.

I have a like problem with an '85. I also have an '86 with the Z51 package and they of course handle completly different. But I have this problem in the '85 where it has an odd feeling, similar to yours when it shifts. Especially when it is winding out and shifts. Not too noticible at city speeds but coming onto a feeway when I am accelerating rapidly it is very noticible. Also above 65 I have a growling sound akin to a bad wheel bearing. I replaced the left front bearing because it had a little bit of play in it. But that did nothing for the growl. I am less worried about the growl then I am about the shift feeling in the car.
The '85 only had 37K on the clock when I bought it. These symptoms came with the car. So I doubt it is an aging problem. Although I have heard that when a car is stored the wheel bearings could be come a problem because the grease sets up in them.
Any ideas guys? I have taken in what you told Fred and I will have the rear checked and get a 4 wheel alignment. But it is beginning to sound like I am not the only one with this problem.

Thanks for your help..........

 

[Bill C]

Bob

My 85 has 175K on the odometer and rides like a dream. I've been to 145 and it seemed like I was doing 90. :cool The only problem that I have is the tendency for the car to follow ruts in the road (the ones trucks make) and that seems to be a C4 class problem. The only suspension componets that I have replaced is all of the Ball Joints and shocks. The rack and pinion is starting to stick when its very cold out but thats another story.

I would spend some time with EACH suspension componet. Pry, twist and wiggel each part and try to see if they exhibit ANY abnormal flex at all. I use a large pry bar and vise grips. Clamp the vise grips on strut bars and you can pry them laterally.
I have had very good results at finding suspension problems by chocking the front wheels, setting the parking brake and (basicly) power braking it to stress the drive line componets. If some CAREFULLY watches each wheel while it's trying to push against a chock,, you may see some abnormal flex or twist. REMEMBER,, you have rubber bushed componets and some flex is normal. Thats why a proper alignment is crutial!! It compensates for that NORMAL flex!
You can also rock the car from side to side while someone observes the suspension componets.

Give that a try and let us know what you find out.

Bill C

 

[vetter1986]

Vibration at 65 MPH

No alignment will correct a vibration ever. Vibrations are usually caused by runout on the wheel assemblies or halfshaft/driveshaft assemblies. CHeck this out first

 

[Bill C]

Vetter86
I wasn't trying to state that alignment was part of the problem. The point that I was trying to make was that; when trying to find a suspension componet that is bad during the flexing of the componets, each part all will flex because they are suspended in rubber. Its the EXCESS and UNCONTROLLED movement that you would be looking for.

Some people can not understand why car manufactures make componets that are suspended in rubber. Why dont they just use sperical hyme joints? The road noise that would be transmitted to the interior would be REAL BAD. Also the excess stress on the system would cause the componets to fail much sooner than we are use to.

Cars are aligned to compensate for all of that flex that the rubber componets provide and under go when the car is rolling down the road. Almost all cars have the front tires set to some degree of TOE IN
Corvetts have front AND rear TOE IN because of the independete rear suspension to be able to compensate for those RUBBER MOUNTED COMOPNETS!

BILL C

 

[fred porter]

well guys i got u joints for the half shafts today, that seems where all the wiggle is coming from. i ll try that first and see if thats the problem. i ordered a bushing set for all the rear parts. and i guess the wheel bearings if there bad will be next. i figure ill try the cheaper way first.

 

[Bill C]

Fred

Be careful when you press the universal joints out and back into the 'ALUMINUM' half shafts. I use a heat gun to preheat the old cups to help them slide out. Once I've got them nice and hot, I use a BIG "C" Clamp and two sockets. One socket that will just slide through the drive shaft loop and the other socket that is big and deep enough to let the other cup drop into it.

Most of the time when I watch people do U Joints they screw up the little needle beadings in the U Joint cups.

To prevent this I would recommend that you remove the new cups one at a time and put some good quality grease into the cups to keep the needle bearings in place while you are working the new cups back into the half shaft. I would also coat the outside of the new cups with grease to help them slide back in.

As you are pressing the new cups together, rotate the U joint and make sure that it does NOT start to bind up. It will be a little bit stiffer than the old ones BUT it should NOT bind or feel rough! If it does I normaly press it back out and make sure that a needle didnt fall down into the bottom of the cup.

While you have the shafts out, you can clean them up so that their nice and shiney.

Bill C

 

[Drewser]

I had a similar problem when I bought my 84. Rode like a dream till you hit 75, then she shook like a dancer in Daytona Beach. I got two new tires and a 4 wheel alignment and it fixed the problem right up. I haven't had it over 125 yet but there is no vibration at all anymore.
--Drew

 

[Bill C]

Drewser

Come on,, I can hit 125 at least three times a week. The trick is to hit 150!

Just kidding.

I've had the 98 up to 150 and the 85 to 145 but the testostrone levels ran out quick as I thought about the ticket , jail cell, car on a wrecker, wife all ****ed off :eyerole and the drivers licsens in the trash!!!! COPS around here are as thick as flies!
I DONT go that fast that often but when I do YEEEEEEEEEE HAAAA, I sure do enjoy it!

Funny thing , the 98 gets up to 150 real real quick! Then it seems like getting to 175 takes forever. The 85 gets up to 130 real real quick but getting to 150 takes forever. So I guess that's why 120-130 seems like the everyday quick blast speed in a basically stock C4.

Bill C

 

[Drewser]

runnin outta road

There are a lot of hills around here and frankly I run out of road over 125-130. The cops have a hard-on for anything over 100 and they really like pulling over red corvettes. I've been lucky so far that I've picked the right times to have the heavy foot. I'll find a place to go 150, I know my bike will do it, been there done that--but it sure got there a lot faster
-Drew

 

[Bill C]

I got a quick bike too! Only had it up to 140 for all of the same reasons! Its new and you have to get use to something on two wheels that will take you to 180 MPH in 1/3 the time it takes you to get there on 4 wheels! That 140 blast only took about 10 seconds Hee HEEE.

 

[David-F]

Vetter1986;
That's not altogether true, to much negitive camber in the rear suspension can give you a vibration because it causes to much angle on the "U" jionts. It is true that in most cases vibrations are not related to aligments but seeing how rear suspensions on a C4 tend to go negitive over time it is something that has to be looked at in a case that the tires and wheels have already been looked at. I will state that torque steering in a C4 applying or letting off the power is a good sign that there is a problem with the rear tie rod assembly because of the toe change you can get when the inner jiont goes bad.

David Fulcher

 

[Bill C]

Fred

Soooo,,, Hows the vette driving now! Did you get rid of the wiggel wobbel???
Let us know how your doing
Bill C

 

[boblx2a]

1984 vibrations

I sort of expected something with the rear suspension. I also have a growl, sounds like a wheel bearing, that is pretty pronounced over 65. I have had the car since it had 37K on it and now it has almost 43K. The growl has not gotten worse but the experience I have had with C4 rear bearings has been all bad! So I was not in a hurry to dive into it unless it got worse. But I suppose I need to deal with it or be left on some dark, rainy road some night.

Thanks for your input. This seems to reinforce my opinion that there is someting amiss in the rear quarters. I really didn't expect to have to begin working on that part of the car with only 43K on it. My '86 had over 100K on it before I started having to work on it's driving parts.

Thanks again.........

 

[Bill C]

If you need any technical help just ask. I've done it a bunch of times. Its not hard, just time comsuming

Bill C

 

[boblx2a]

1984 Vibrations

Bill C

Well Bill I have not done this in about 5 years. I did it on my '86 and it took almost all day. As I remember one of the toughest parts was getting that rear parking brake back together correctly. You need a minimum of 3 hands, 4 would help even better.

There were two of us working on it and I remember wishing I was plastic man so I could get my hands in some of those places. Like you alluded to, mostly just drudgery. But when it has to be done there are no options.

I don't know right now if that is the problem. Those are pretty tough bearings. The one I did I think had been done by the previous owner and he failed to torque the nut. Because when I took it apart I could remove that nut with my fingers. And when I got the bearing out there did not appear to be anything wrong with it. But after doing a job like that I was not about to have to do it again so I replaced it with a new one anyway. I still have the one I took out. Don't know why. I guess I thought some day I might use it but I know I would never put it in anothere car for the same reason I didn't reuse it in the first place.

Thanks for your offer. I'll let you know what I find on Saturday.

........