Vibration

[jackb]

Everytime I kickdown on the highway, I get a vibration that persists for a while until I slow down < 40 MPH. Take it out of gear-it still vibrates.

[whacker]

Could be warped brake drums, could be out of balance wheels, could be misaligned center universal joint, could be bent axle shaft or bent drive shaft. My bet would be center universal joint either worn out or improperly reinstalled.

[HookedonStudies]

Check the tires too.

55 Commander
58 Transtar
62 GT Hawk
66 Cruiser

[jackb]

I can near confirm that this symptom was present before I performed the brake job, replaced both U-joints, and a bunch of other stuff...I really think I know what it is: old tires. They are low miled radials with few good tread on them, but they are at least 15+ years old.....glass radials to boot. I'm getting an alignment tomorrow (Tuesday 1:30) and don't know if I should spend much money on looking at old tires ??? Balancing etc....After taking the steed out for a spin tonight, I realized the vibration is above 60 mph. These tires haven't been on a car for at least 5-6 years..been in the basement with 15 lbs of pressure since then......

[jackb]

Correction: With "good" tread left on them...

[leyrret]

15 year old tires will more than likely come apart on you. I would trash them.

[55s]

I agree. Old radial tires are scary, becasue they start to come apart internally. 10 years max.

Paul

[buddymander]

An out of round tire or a tire with a belt shifted will vibrate on the front end at least ten times worse than on the rear. Jack up the front and spin the tires looking for a wavy sidewall. Switch any suspect tire with one from the rear, but better check them the same way first. Dry rot danger in an old tire is from the days of cotton cords. Polyester, nylon, and steel belts don't rot. All that happens is the rubber becomes porous and you slowly lose air. I'm sure this post will incite many doomsdayers, but I've run many a questionable tire from out in the middle of nowhere and was surprised time and time again by their ability to perform after various types of abuse and neglect.

[gordr]

Steel-belted radials may not suffer from rot, but they sure as **** can suffer from rust, particularly if they ever had a puncture that was patched. A friend of mine has X-rays of steel-belted radials showing rust damage to the steel belts. I should scan them and post them somewhere.

Also, the rubber itself in old tires gradually loses its resiliency from the effects of sunlight and ozone. Old tires may hold air alright, but they simply won't drive as well as new ones. It's as much a comfort issue as a safety issue, IMHO.

Gord Richmond, within Weasel range of the Alberta Badlands

[leyrret]

If you run a 15 year old radials and they don't come apart you are one lucky S.O.B. Old radials will separate. This is fact. I've had them do it. Had one explode laying in the back of my pickup. My understanding any tire setting to long will dry rot as the oil in compound doesn,t
get circulated by tire movement. It's not the cord that dry rots but the compound used to construct it. In fact, in my experience, old nylon tires hold up better than steel belted.

[John Kirchhoff]

I agree with the other guys, radial tires can look good but cause vibration or pull to one side. The best way I've found to rule out the tires are to put the spare on, try it and if the problem is still there, move the spare or use the tire you took off to another corner and so on. Back in the early days of radials, the Firestone 721 was notorious for going bad and cost Firestone money and reputation. One morning I noticed a piece of rubber laying under my truck. Ends up the 721 spare had twisted out of shape and popped the tread off while it was just hanging there.

[jackb]

Well...I'm back from the alignment shop and have some fairly bad , but some intersting info.....1st: The mechanic could not get the correct amount of CASTER. He asked if the car was ever in a wreck and I confirmed that it was (a significant one, requiring new doghouse and frame)....anyway, he stated it (caster)was "close" but not perfect. He said he could probably correct it if I left it with him for a day....He also commented that he had sold the very glass belted tires on the car back in the 80's and said to "drive them". He did suggest that swapping sides or position(s) might correct things. The car still drifts to the right if I take hands off the wheel....not bad ...but what's bad ? It seems fine when I think of comparing it to my new truck!?.......And I just thought of this....I pulled these tires out from the basement. The tires that came with the car were brand new Michelin's but were wrong size and rims were painted hot rod red.....They're in the basement now...When I had those tires on the car ..the car drifted right but did not vibrate at any speeds.....mmmmmmm

[jackb]

More info..months later. While attending to some brake issues (disc brake rears are a bugger to adjust new) , and finding that I had too much endplay (shimmed with bearing full of grease vs. dry)...I have now eliminated some/most of the vibration. I decided to swap the fornt tires right to left. Now, instead of pulling slightly to the right, it pulls strongly to the left. I checked tire pressure and the left side was 2-4 lbs more.....!? Time for new tires...

[BobGlasscock]

With what I admit is a limited technical knowledge of caster, I would easily imagine that if it isn't right (and even on both tires) it could produce a pull, due to the hub not being exactly the same "off" square to the ground as the other hub. As for the tires, I agree with everyone who says to change them. My motorhome develops the same problem after a couple years of age and a season of parking. The thump vibration will lessen with use each year, but the carcass just deteriorates too much as compared with the tread.

'50 Champion, 1 family owner