: Seeking Front End Advice



Timothy60
05-12-06, 08:03 AM
I have a vibration concern on my 1993 Fleetwood. The vibration telegraphs through the steering wheel at speeds between 38-70 MPH. It's not like it shakes the steering wheel out of my hand, but it is very, very annoying. I had the tires balanced and rotated by two different shops and the technician told me yesterday that the tires are balanced properly. The vibration is unaffected my transmission gear selection, including neutral. The brakes feel normal and do not pulsate. There are no unusual noises. The u-joints are new. What do I do next?

77CDV
05-12-06, 03:37 PM
Can you describe the vibration more precisely? Did the tire rotations make any difference? Does it seem to pull to one side more than the other? More info, please.

Craig

Timothy60
05-12-06, 08:43 PM
No, the tire rotations made no difference at all. No, it doesn't pull to either side. The car tracks straight and true. There are no unusual noises. At slow speeds, it feels fine. When I get to about 38 MPH, it starts to feel like a wheel (or wheels) is out of balance because there is a shake in the steering wheel. Yesterday I went to a local tire store and they computer balanced all four wheels and said they are all A-OK. But when I went out on the highway, that annoying vibration started again! The vibration feels like I'm going over little ripples or bumps in the pavement. Oh, and it gets worse the faster I go up to about 63 MPH and then it seems to get better around 72MPH.

Could it be a wheel bearing out of adjustment? What is your opinion?

77CDV
05-13-06, 01:44 PM
At this point I'm down to worn bearings or spherical joints, though I can't see it getting better as you go faster. Unless there's some problem in the PS pump which "corrects" at a certain speed. Weren't these cars built with a variable PS system that increased resistance (relatively speaking) with increased speed? That's all I can think of. Sorry.

Craig

N0DIH
05-13-06, 02:06 PM
Sounds like it might be a blown shock. If it is weak or blown, the wheel will bounce. Change airpressure temp to around 45 psi and drive, see if it changes. Often a wheel bounce will be affected by air pressure.

Have someone drive next to you when it is doing it examining all wheels.

WMD
05-13-06, 04:17 PM
If the front end appears ok I would also have a close look at the drive shaft and U joints. Certain vibrations can be elusive.
Good Luck WMD

N0DIH
05-13-06, 07:57 PM
U-Joints are load sensitive.
Wheel bearings change noise in turns, louder/quieter. And over bumps that can get the car to lift up some.
Driveshaft out of balance is typically vehicle speed sensitive, not engine rpm sensitive.
Shocks are vehicle speed sensitive, but are affected by tire pressure.
Wheel balance gets worse with speed. Faster is worse.
Ring and Pinion noise is load sensitive. Often no noise at coast, no noise at load, and noise at light application of power (increase load). Frequency of the noise is often directly related to the ratio of the ring an pinion.

Give that some thought.....

Junkman
05-13-06, 11:32 PM
............ The u-joints are new. What do I do next?

I have been following this thread for a while now, and have been thinking about it the replacement of the u-joints. It is possible that a weight was knocked off the driveshaft while it was out.

Timothy60
05-14-06, 03:18 PM
The vibration was present before the new u-joints. I thought that the vibration may be from the u-joints, but I was wrong, the vibration did not go away. I jacked the car up yesterday and had a good look around the front suspension components. Suspension diagnosis issues go beyond the skills of the average Saturday afternoon DYI mechanic like me! Would a shock that is shot have oil seeping from the cylinder? The shocks looked clean. Tie-rod ends seem OK. Would a worn drag link cause a vibration? I'm stumped on this one. I'll try pumping the front tires up from 30 psi to 45 psi and see if it's a blown shock. Then I suppose I'll have to (frown) . . . seek the help of a good front-end garage and get the checkbook ready for a big hit. I'll let you know what happens. I depend on this vehicle to get me to and from work every day, so I really want this fixed before it gets worse or something breaks and leaves me stranded on I-81. Thanks for your help and advice.

Junkman
05-14-06, 04:54 PM
Lets take this one step at a time..... How much mileage on the car?? Have the shocks been replaced or are they the same the car was delivered with? If they have been replaced, then how many miles ago? Have you jacked the car up and checked the front wheel bearings? To do this, jack the car under the front lower control arm, and spin the wheel, and listen for any noise. Then push the tire with your hands at the 3 & 6 o'clock position, just enough to find any looseness. Then using a long bar, lift the tire at the 6 o'clock position and check the ball joints. Then do the other side and use one side as a comparison for the other, and if one test is different on one side than it is on the other, further investigation is needed. Were the tires ever swapped from side to side? Sometimes radial tires can only be swapped front to back because of wear and stress patterns. This isn't the case in all radials, but I have seen where it can effect the ride. Also, a bad bearing in the steering box can also cause a vibration, but it is unlikely, unless your car is extremely high mileage. The next time that you get the vibration, gently apply the brake and see if the vibration goes away. If it does, then the vibration is somewhere in the wheels. If the car has alloy wheels, are they all torqued properly? I am guessing at straws, but that is what it is going to take to figure out difficult problems... Thinking outside of the normal problems that cause the vibration. Something is out of balance, so finding it will take time. Also, next time it happens, put the car into neutral and see if the vibration goes away. It might be a in-balance harmonic that is coming from the engine. Also try shifting into a lower gear or if you can disengage the overdrive system. I suggest these two last things not knowing the specifics of your car... Junk...

WMD
05-14-06, 06:01 PM
Tim
Thanks for posting back about the U joints being replaced after the vibration began. Be advised however that the SLIGHTEST dent or possible fault seen on the driveshaft itself COULD cause a vibration.
WMD

Timothy60
05-14-06, 09:46 PM
Thanks for all the suggestions! Now I feel a bit more informed about the possibilities of what might be going on with the front end. The Fleetwood has 155,000 miles in it. From what I can tell after looking around under the car, the original owners didn't seem to replace anything except the brakes. Of course, that's just a guess. I bought it from a quiet, elderly couple who seemed to cherish it and were concerned that it was "going to a good home". (It did.) I've put 12,000 miles on it since I bought it last October and it's been smooth as glass until I had the snows removed and the tires rotated at the end of April. That's when the vibration started. The vibration does stop when the brakes are applied gently. I have swapped the front wheels but that had no effect.
Anyway, I jacked the Cadillac up again and shook the front wheels while holding them at 3 and 6 o'clock. There is free play present. Could that be a wheel bearing? There was no grinding sound as I turned the tires except for the sound of the pads brushing against the disc. Now that you've given all this information, one extra consideration comes to mind: The vibration seems to get worse the longer I drive it. For example, as I'm getting closer to work on the highway, it seems to be more pronounced than when I just get up to cruising speed. It does not go away in neutral, either.
I can't check the ball joints in the way you described because the light in my garage isn't the greatest at night even with a drop light. I'll look into that tomorrow.
I'm pretty certain the drive shaft and u-joints are exempt at this point. I'm sure with your help I'll get this pesky problem resolved soon. I'll keep you posted and thanks for your time and suggestions.

Junkman
05-14-06, 10:02 PM
Swap the front wheels right to left and left to right. If they crossed the wheels, there might be a problem in the radial belts that is causing the problem. Also, when the tires become warm from use, they could have a shifting steel belt in the tire. Also, when you get to work, with the wheel covers removed, feel the front hubs. They both should be cool to the touch and even temperature wise. If one is hot, then that indicates a problem in that wheel. If switching the front tires doesn't help, then swap them to the rear .... right front to right rear..... Left front to left rear... If you still have the vibration, then swap the fronts again right to left and left to right. If after all this, you still have the problem, then we will have to go into this deeper...... It is trial and error time, because there isn't much left. At least you are only spending some of your time, but none of your money at this point. Junk.

Timothy60
05-15-06, 11:32 AM
I was thinking about all the various ideas people had about this front-end vibration so I went back out into the garage at 10 o'clock at night for another look. I removed the cap from the hub and looked inside with a droplight. There was a blob of grease inside the cap and some dried-up grease around the nut and cotter pin. I could see the bearing and it was shiny! Isn't it supposed to be embedded in grease? What does a well-lubricated bearing look like? I'm not sure, but I will hypothesize that it should have at least some grease available for the rollers.
Well, it was late so I did a very unsophisticated thing. . . I took a clean, new pencil and pushed some of the grease from the cap into the rollers. Now at least they had a little bit of grease available. Put the cap and hubcap back on, lowered the car and called it a day.
This morning I drove to work and guess what? No more vibration! It must have been just enough grease to give the bearing a bit of lubrication. Now what should I do? I suppose I need to remove the wheel and bearing, clean it, and repack it? Is there an inner and outer bearing? Do I need to remove the brake disc?

N0DIH
05-15-06, 11:49 AM
Sounds like you found it, dry bearing. They should be repacked every 30K miles or so, around every 2 years MAX. By all means get a look at them right away. If you gall the spindle it is pretty pricey to fix. We lost both front wheel bearings (cracked races) in 2 miles on my 76 Delta 88 on a trip back in the late 70's early 80's. Due to lack of repacking bearings. It came close to being VERY expensive. We hit a small bump and CRACK and then a light popping/grinding noise from in front. We pulled in to a shop, he pulled the tires and when he pulled the rotors, the bearings fell on the ground.... Both sides. NOT good...

REPACK YOUR BEARINGS RELIGIOUSLY!

If Katshot is around, what did you guys use for the limo fleets for bearing repacks?

Junkman
05-15-06, 12:10 PM
To properly grease the bearings and check them you will need to first remove the caliper from the rotor. Then back off the nut and pull everything out. Then you can put the nut back on until it is flush with the end of the spindle and give the rotor a yank. This will cause the rear bearing to grab on the nut and pull out the rear seal. The other method is to just pull out the rotor leaving the rear bearing in and pry the rear seal off. I would replace both inner and outer bearings and races along with a new seal. They are not that expensive and there is a good chance that the outer bearing is already been stressed. Using the nut on the spindle to pull the rear bearing can sometimes damage it, but if you are replacing it, then it doesn't matter. Glad to be of assistance. Junkman....

Timothy60
05-17-06, 11:22 AM
Good news! I removed, cleaned, and re-packed the front wheel bearings and installed new seals. The bearings were in good condition, but getting dry. Everything went well; no problems. Buttoned it back up with anxious anticipation.

Bad news! Took the Fleetwood on a test ride and. . . vibration still. No change. At least I know the bearings are good now. I've made an appointement to bring it into the shop tomorrow. I give up and I'm tired of switching tires and all that other stuff. I failed. I suppose this is a job for a professional to fix because it's beyond my skill, even though I had excellent help and suggestions from all of you for which I am grateful. Thank you.

scurling
05-17-06, 09:48 PM
Let us know what they find, and you didn't fail. You learned a lot. Store it away, or even make notes and start a maintenance notebook with your own diagnostics section. I have a file folder full of maintenance articles that I keep as reference.

Timothy60
05-18-06, 07:41 AM
Good idea! Yes, I learned a lot. People here are willing to share what they know. I just dropped the Cadillac off at the garage. They want to keep it all day and take it for a test drive in order to diagnose the vibration issue. I'll let you know how this turns out. I'm anxious to find out what they discover, too.