Mechanics

INTERMITTENT RUMBLING VIBRATION AT HIGHWAY S

1995 Geo Metro

Noises problem
1995 Geo Metro 4 cyl Front Wheel Drive Automatic 100000 miles

Car is in good repair & well maintained. Most work done by me except AC. Remarkably tough little car - wasn't sure what to expect when I bought it but have been pleased except for some underbody parts that seem prone to excessive rust (Ohio car). Biggest job I've done to date was replacing timing belt.

Rumbling noise & vibration first started about 2 months ago. Very noticeable when it starts and eventually quits by itself after a minute or two. Noise comes from the front but can't discern a side. Also been very intermittent (so far) and only at highway speeds (> 60 mph). Happened again yesterday after nothing for over month. CV joint boots (inner & outer, both sides) are intact and in good shape.

From Haynes manual and at 100K miles, a deteriorating CV joint(s) make the most sense.
1) Which ones are prone to go bad on a Geo?
2) Best strategy approach? Replace all, outer ones only, etc.
3)Inner and/or Outer & how to determine?
3) Best place to find parts and which ones should I buy- local or web for a Geo?
4) Can I tackle this in my garage with the car on jack stands or be better off at a mechanic shop? I have impact tools.
5) Anything else you can tell me that I don't know enough to ask about this potential repair?
6) Other potential causes besides CV joints (brakes in good repair, front struts look OK)?

Thanks for the help.
Jeff Black
Avatar
Djeffreyblack
January 28, 2009.



Before you replace any CV axles, try this. Drive the car under the conditions necessary for it to make the noise/vibration. When it starts doing it, make a sharp, quick turn of the steering wheel to either direction. (As if you were dodging something in the road all of a sudden) Did the noise/vibration momentarily go away or change at all? We're checking for a bad wheel bearing by doing this. When a wheel brg goes bad, it will growl, groan, moan, vibrate, etc. It will sometimes sound like 'road noise', only amplified.
If the CV axles/joints are failing, you will hear a 'clicking' noise when making fairly sharp turns, either in reverse or going forward. It will usually be worse in one direction than in the other, unless BOTH are going bad. Try checking the wheel bearings first and get back with me.

Tiny
Jasonray
Jan 28, 2009.
Jason - Thanks for the reply. I have not been able to intentionally induce the condition while driving on the freeway. Your description of the sound as " amplified road noise" is a better description of the sound plus the vibration is noticeable but not alarming (at least not yet). In past episodes, normal highway lane changes did not stop the noise but can definitely say that there is no " clicking" component to the noise. Making the sharp turns you described in forward /reverse does not get any noises or clicking so the CV joints are probably not that good of a candidate.

I have wondered about the wheel bearings before because they were not listed on any of the normal maintenance schedules I have for the car. In fact the Haynes manual I have only covers the rear wheel bearings and does not even mention the front ones.

Can you recommend a better manual that is reasonable priced? I'll have this car for a few more years before the Ohio road salts gets it. I actually like working on the little thing.

I have no objection to replacing the front wheel bearings. This condition sounds more likely than the CV joints. Somethng is definetly not right. Plus I would rather have it on my repair schedule instead of the reverse. I also had a front wheel bearing go bad on another high miler a few years ago but the rumble/vibration was constant rather than intermittent.

What is your recommendation? What about servicing the rear wheel bearings while I'm at it? Thanks again.
Jeff Black.

Tiny
Djeffreyblack
Jan 29, 2009.
It's sometimes my policy to 'don't fix it if it aint broke', however, preventive maintenence can be worth it's weight in gold. So, if you choose to replace the rear wheel bearings, you certainly won't be going wrong.
Normal lane changes probably won't indicate a failing wheel bearing. I wish I could say 100% that's what it is but, based on the info I'm getting, I can't. Wheel bearings usually won't be intermittent, but if road conditions change, or driving habits or conditions change, so can the noise from wheel bearings. Several factors come into play during normal driving. Could there possibly be TOO much air in one of the tires? That could also create a 'road noise' sound as well as a vibration. If, in fact, it is a wheel bearing, rest assured that it will get worse. When it does, you should have better luck pinpointing it. Try raising the front wheels off the ground and spinning the front wheels by hand. Keep your hands on the tire and turn it slowly in both directions, paying close attention to the feel of the tire. Can you feel rough spots or 'bumps' while you're turning it? Those bumps, at highway speeds, will become a roar and a vibration. Keep in mind that the weight of the car is NOT on the bearings at this time so you may or may not feel anything, even if it IS bad.

Tiny
Jasonray
Jan 30, 2009.
Jason - Thanks for your help. Problem solved. Found out how to check front wheels for bad CV Joints from another mechanic friend with more experience. Jacked each front wheel off the ground under the control arm. Both right & left joints were bad. Replaced both in a few hours for $120 in parts, not the $350 the garage quoted. Front end feels good & solid now when driving.

Redid the back brakes over the weekend. Grinding was from a lot of rust powder in the drums which could not get out. Cleaned & painted the rusty pars with something called " Chassis Saver". Have used it several time on this car and it is excellent. I'm a chemist during the day so this is something I can comment on with some knowledge. The rear wheel bearings looked fine so I lft them alone.

The baby car is ready to go for a few thousand more miles. Thanks again for your help.

Tiny
Djeffreyblack
Feb 9, 2009.