Sup everybody-I've checked the archives for stuff and I haven't found anything specific even though I have found some people w/ the same prob. I've got a '92 RS-127,850 mi. (this may or may not be relevant, but want to make everything clear) It's been in a front end collision, but it has been "fixed"
So what's goin on?
Well, before I put 4 brand new tires on, it used to shake at around 70 mph-put the new tires on cause that's what the mechanic said it was-well it still did it.
Changed my fuel filter couple weeks ago and it stopped for one drive on the highway-then it started again that next weekend, but at around 75....
And to clarify on the "shaking"-it's all in the front end. I can seed the hood vibriting-my dash shakes really bad, and if I'm wearing a watch on my left hand, I have to drive w/ my right because the rattling gets too annoying w/ my left hand on the steering wheel.
Now I'm thinkin it has to be somethin screwed up w/ the front end or maybe it's just the fact that I've got a butt load of miles....(not as much as some of you -you guys rock) This is really starting to get under my skin because I make a 414 mi. drive-to and from-and three hours in the car about 2 weekends a month-sometimes more- and I can't handle it-I need a smooth ride-at least a smoother ride than that (know the f-bodies aren't known for ridin like caddies...) And on top of this-I've got some 17x9 SS style rims that are goin on my car this weekend-this gonna make it worse???
Sorry for the length and thanks for the help.

 

You might want to post this on the Suspension/Chassis board, I've seen the topic covered many times before in there. Are any of the front wheels bent? Try snagging a friend's set of wheels/tires and see if you get the same problem.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Could be the wheel bearings?

 

bent rim?
bad tire?
unbalanced wheel?
worn wheel bearing?
wore-out driveshaft u-joint?

 

Most common is that the tires are out of balance... If you got new tires and they were balanced it should have gone away. The next most common would be worn out U-joints as said above... and sometimes the driveshafts are very poorly balanced. I get a little shaking around 90 MPH, but not as bad as you're talking... I plan to replace the driveshaft with an aluminum one that came on [IROCs?] the RPO code for that is JG1 if you're interested in hunting one down.

If this all happened just after the collision, then check for busted bearings and wheel wobble... Finding the solution could save you a lot of money in the long run... you can't imagine how expensive it will be if you lose a front wheel goin 70 down the highway...

 

that brings up another point ... are you sure the lug nuts are nice and tight?

 

tire unbalanced

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Sgt Panther

89 Firebird..2.8/3.4 conversion

 

Dont forget worn struts/shocks can cause vibrations

 

what about front end alignment. wouldn't that cause it?

 

i had same problem and it was the wheel bearings. tightened those puppies up and now it is a smoother ride. my alignment is wasted but fixing that this friday.

 

After your brake job, they didn't seat the bearings correctly.
Pull off the front wheels and retighten the bearings.
OH YES, larger wheels and tires will make this problem MUCH WORSE.
BUT THAT'S GOOD.
Use it to narrow down problems.
CAN also be shocks.
Don't laugh at that, it was with my Wife's 1968 Camaro.
But, yours is bearings. Repack again, tighten more.


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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

i had the same problem, i had the tires rebalanced twice. it still got the nasty shakes at 70. My friend, check the steering components. Mine needed a new centerlink and that was the end of that. just jack the front end up and wiggle the wheels. See what is loose. I hope this helps, if you haven't solved it yet. good luck, Evan

 

Good point, Evan... the center link is a "wear" item on our cars.. meaning, it's common for it to wear out somewhat early. This is more so for the idler arm... get that checked, too. I had both of mine changed back in '96, and it was a big difference. I was thinking about changing them again... it's been over 100,000 miles since then.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Well-I'm driving home for thanksgiving break-we'll see how bad it still is-I'll check the centerlink (is that what you said?)-I've changed AN idler arm....I'm thinkin that may be it too-probably should've changed both.....