Bad vibrations... What could it be?

[hansvdweerd]

Hello all!

Since a few weeks I've been experiencing some not so good vibrations in my Ex ('98 SOHC).

When driving in the city the problem isn't very noticeable. When driving on the highway a kind of high pitched vibration starts around 80 km/hour. The vibrations seem to come from the body of the car and not so much from the steering wheel. I can feel the vibrations in the dash also. I can't really say the vibrations are coming from like the front or the rear... When I take my foot from the gaspedal at that speed the vibrations seem to get a bit more intens.

What did I do up till now:

My mechanic visually inspected the suspension and didn't find any apparent damage or failures. He advised me to balance the tires (front and rear) and align everything.

And so I did.

I much say the car handles better (so balancing and aligning was in it self a good thing to do) and even my steering wheel is in the correct position now, but the vibrations are still present...

I did notice that one of the hooks or hangers (is that the term for it?) of my new exhaust touches the chassis of the car. Saturday I'm gonna fix this. The vibrations were however already present when I still had the old exhaust.

Could it perhaps have something to do with the engine mounts?

Where should I start?

Thanks in advance for your help!

Kind regards,
Hans

 

[gmanpaint]

Try replacing the 5th shock. They were developed to dampen the vibrations at higher speeds.

Make sure the cast weights are on. There is one on the rear axle, and if your AWD or 4x4, there is another on the t-case.

Try swapping front tires for the back tires.

Tie rods will play a role as well. The inners are impossible to visually see if they are bad, but can be figured out by feel. Does the vibrations go away while turning the wheel around a bend / corner?

 

[hansvdweerd]

I did some research in the meantime.

- Does a vibration you feel throughout the car indicate that your problem might be in the rear suspension?

- Do problems with the driveshaft result in constant vibrations/shaking and not only at higher speeds?

- Does anyone have experience with dynamic balancing (with the wheels on the car) on a car with automatic transmission?

The car otherwise runs fine, shifts on time and has normal fuel economy. No codes, tranny filter, fluid and gasket changed a few months ago.

The hard part is that I'm very impatient, you might call it my character flaw, and I have to wait a few days before I can get the Ex in the garage

 

[ucluglee]

I had an almost identical issue on my old Ranger. The driveshaft lost it's balancing weight. $20 got it rebalanced and all was well.

 

[gmanpaint]

Good call on the drive shafts, I forgot to mention those. A bad set of U-joints can also cause a wobble.

I run tire balancing beads in all my vehicles. Cant say enough good things about them.

 

[hansvdweerd]

Try replacing the 5th shock. They were developed to dampen the vibrations at higher speeds.

Make sure the cast weights are on. There is one on the rear axle, and if your AWD or 4x4, there is another on the t-case.

Try swapping front tires for the back tires.

Tie rods will play a role as well. The inners are impossible to visually see if they are bad, but can be figured out by feel. Does the vibrations go away while turning the wheel around a bend / corner?

Thanks for the input!

With regard to your question: I can't say for sure. That's the problem with testing it on the highway: very few bends that really allow you to turn the wheel significantly at high speeds. But on my way home from work in a few hours I'll take the more scenic route and test the vibrations while turning the wheel.

And this is probably a dumb question: the 5th shock? Where do I find that one?

 

[gmanpaint]

5th shock is the small shock attached to the rear axle and runs to the frame rail on the passenger side.

91 to 94 had what was called the "Death Wobble", and in 95, Ford introduced the dampening shock to counter balance the problem.

 

[hansvdweerd]

I had an almost identical issue on my old Ranger. The driveshaft lost it's balancing weight. $20 got it rebalanced and all was well.

Okay, I'll be adding this one to my checklist as well. Might explain why the issue came up all of a sudden.

Thanks!

 

[corkey]

i had a similar shimmy in my 1996, and it would not go away, i changed everything, i thought,,
turns out i checked all the rear u joints and they appeared fine, but the front u Joint was dry and rusted inside when i changed it out, couldn't see if , and it felt fine.

now silky smooth ,,

 

[ThePhoenix]

I was gonna say "well its NOT the Beach Boys"...

I had similar issue...Mad vibration at 60...OK under 60. Turned out to be bad wheel bearings (RWD) on the front left

simple fix, hard to find

 

[hansvdweerd]

i had a similar shimmy in my 1996, and it would not go away, i changed everything, i thought,,
turns out i checked all the rear u joints and they appeared fine, but the front u Joint was dry and rusted inside when i changed it out, couldn't see if , and it felt fine.

now silky smooth ,,

My checklist is getting longer and longer! Good to hear that there were solutions to similar problems.

I must say that I'm very pleased that my mechanic lets me 'fool around' with my Ex (while supervising everything off course) on Saturdays. I've had three cars before my Ex (Saab and Peugot), but the Ex is the one I know the best and can, to some extend, work on myself.

It's extremely satisfying to solve a problem without paying big bucks on labour costs

 

[ThePhoenix]

=it's extremely satisfying to solve a problem without paying big bucks on labour costs :d

amen

 

[hansvdweerd]

I was gonna say "well its NOT the Beach Boys"...

I had similar issue...Mad vibration at 60...OK under 60. Turned out to be bad wheel bearings (RWD) on the front left

simple fix, hard to find

As I was typing my original post I immediately thought of them!

 

[hansvdweerd]

Checklist

Okay, this is my checklist for tommorrow:

- u-joints (Haynes manual states that when the vibration is only present at a certain engine speed in a certain gear (or in 4th or OD), that's a good indication that the u-joint(s) are defective. Vibration in all gears usually indicates an unbalance)

- sway bar bushings, especially in the rear

- wheel bearings

- balancing weight(s) drive shaft

- 5th shock

I'll let you know how it turns out!

 

[hansvdweerd]

Fixed it!!!

Well, the bolts on the rear u-joint were so loose I could turn them by hand!

That was a disaster waiting to happen... I tightened the bolts and used that stuff on it to prevent the bolts from coming of.

Furthermore I checked the driveshaft for any mud clinging to it and checked if the balancing weights were still on it. The sway bar bushings were all in good condition, as was the fifth shock.

I also bent the exhaust at the end a bit (after heating it) so it was completely clear of the chassis (now I know why the exhaust was relativly cheap: it ALMOST was an exact fit )

Took the Ex for a testdrive and all was well. What a relief!

Thanks for your input, guys!

 

[Brian T Nickless]

Great English !

Just a note on your excellent use of English ! You had good teachers ! BN

 

[Blee1099]

When are the vibrations good?

 

[hansvdweerd]

Just a note on your excellent use of English ! You had good teachers ! BN

Thanks for the compliment!

 

[Afboy143]

Interesting thread as I have a nice vibration at high speeds and it scares the crap out of me! I have no front wheel bearings. Replaced those when I put on slotted rotors. Tires are all aligned. Did that when I replaced the front inner and outter tie-rods

My question is this:

5th shock- Didn't know our trucks had this! Worth replacing anyway at 135k?

U joints- I did some googling and a U joint don't have bolts on it like the U bolt would have. U joint is on the drive shaft to the rear end. U Bolt is what holds the rear end to the leaf suspension. What did you fix/tighten?

Someone said front U joints... where is this? I have 2WD, would I have this?

Thanks Fellas

 

[hansvdweerd]

U joints- I did some googling and a U joint don't have bolts on it like the U bolt would have. U joint is on the drive shaft to the rear end. U Bolt is what holds the rear end to the leaf suspension. What did you fix/tighten?

Someone said front U joints... where is this? I have 2WD, would I have this?

Thanks Fellas

I thightened the four bolts at the end of the driveshaft closest to the transmission. I think this instruction video on YouTube might clearify things:

http://www.youtube.com/watch?v=zdDitgOVIL8&feature=youtube_gdata_player

At 00:22 you'll see the four bolts I'm talking about.

With regard to the fifth shock: some people say that driving without it didn't result in a less smooth ride. Others state the opposite