kirk a wolff

Hi all,
I have a 1979 2WD dodge D20 (aka D200) /w 360 V8 with 70k miles
When I first got this truck, it had this problem, but I didn't notice it
until I got out on the freeway. It eventually got worse, its almost
undrivable. It is hard to identify where the shaking is coming from. It
seemed at first like it was the front, then I thought it had to have been
the rear, now I've replaced the rear bearings and spun up the rear wheels at
pretty high speed without any shaking I am fairly convinced that the problem
has to be from the front. If the problem is really from the rear, then it
would be due to an out-of-round tire. While watching the rear tires rotating
they look as round as can be.
At low speeds, below 15 Mph, the whole vehicle seems to shimmy slowly both
the front and back. At high and moderate speeds there's a violent shaking
that seems to shake the front end more than the back. There is a pulsating
underneath the floorboards, the bench seat shakes as well on both sides. It
doesn't matter if its in gear or in neutral, the noise and shaking doesn't
change. Its definitely not related to engine speed.
In an attempt to fix the problem, I replaced the rear bearings, while I was
at it I also replaced the brake cylinders as they weren't working. This is a
spicer 60 full-floating rear axle type rear-end.
When I took apart the rear drums, grease was splattered all around the
insides also made it difficult braking. After taking a test drive after
working on the rear yesterday, it seemed to be not as bad, but today the
shaking is just as bad as it had always been.
In order to attempt to find the source of the shaking, I took the drive
shaft and shook it up and down, front and back, couldn't find anything
obvious. I spun the rear wheels and no strange sounds coming from the
u-joints or anything.
Where is this shaking coming from?
My next guess is to rotate the tires to see if the problem is the front
tires. Next replace the front bearings and check the front calipers and
discs. If I were to guess, at this point I would guess the front discs are
bent, but couldn't this also be a misaligned front bearing? As I have
limited time and money I hope someone here can help me identify what's going
on.

- Kirk

carl saiyed

Try jacking up the front of the truck, obviously, place it on jack stands
for safety. With the steering column locked, grab the tire at the top and
bottom, and wiggle. There should be little to no play. Grab the tire at the
left and right, and wiggle. There should be little to no play. Up and down
play means your wheel bearings are loose/out. Left and right usually means
ball joints.

Hope this helps, please come back with your findings so we can help you get
this figured out.

Carl

lurker

Bent front discs would be felt worse (and throught the steering whell) when
braking.

The drive shaft may be out of balance - that would show up only at highway
speeds.

Or maybe a bad u-joint that would be found by a clunk shifting drive to
reverse with the brakes on.

check for bent rim (not likely) or a broken cord in the tire(s).

Do these before getting into expensive or labor intensive parts.

msyjsy

I would suspect a bent drive-line before I looked any further.
I ditched a car once and it had the same symptoms when I got it pulled out.
But it was bent enough that it was obvious when you watched the car roll
down the street. Yours may not be noticeable just by looking at it, but it
would not take much to throw it out of balance and cause the symptoms you


--
From The
Desk Of: Jesse A. Harrington
"Kirk A Wolff" <kirk@kirk.homeip.net> wrote in message news:PH3vc.33945$zO3.5101@newsread2.news.atl.earth link.net...

dddd

My bet would be the drive shaft. I had something similar happen to an 81
Dodge van and that was my problem. DDDD

kirk a wolff

I replaced the U-Joints on the drive shaft. This is a two U-Joint, single
segment type drive shaft. The clanking went away when I put it in drive,
but... The shaking is still there. I had someone in the car with me last
night (11:30PM) during the test drive. The shaking didn't change one bit.
It seems to come more from the right than the left, and more from the front
than the back. Hmmm... What could this mean? I worked on the rear of the
truck and driveshaft for no reason? The shaking is even pronounced at very
low speeds i.e. 1.5 to 5 MPH. Its as if I'm slowly driving over a washboard
dirt road on that corner of the car even when I'm on perfectly flat straight
road. Its still hard to identify even at that speed since the whole truck
twists and vibrates due to the problem. This sounds very much like a stupid
bulge in the tire! If I could kick myself I'd beat myself to a bloody pulp.
Its crazy that its taken 9 months to isolate this problem. Its possible
that the other stuff was bad too and compounding it, but the major problem
is simply the tire. I'll get back when I replace it with the spare to
verify.

carl saiyed

Did you perform the checks I reccomended?

Carl

miles

Kinda sounda like 1 bias ply tire and 3 radials.

kirk a wolff

I took the tire off last night and replaced it with a full size spare. I
checked for play in the knuckle when replacing the tire, it was very solid
(amazing after that kind of abuse). From the time that this pounding
started until now, the tire turned into a 5000 piece puzzle. The treads
aren't even straight. There's a crack on the inside of the tire about 1/2
from the rim that goes all the way around the tire. The tire isn't even
close to being round. After taking it off, I gave it a push along the
driveway. The treads fluctuate right to left by about an inch. There is
some kind of wire mesh sticking out the side. I'm surprised I've been able
to drive on it this long, its a wonder I haven't had a blowout. I suppose
if I were one of those ditzes that doesn't pay any attention to sounds or
movement from their car I would have ended up with a blowout. Even though
the spare is out of balance (so is the left front tire) comparatively, the
truck rides like a dream. I'll have to replace some tires and move on from
there. 16.5 inch truck tires aren't cheap, I'd almost rather replace a
steering knuckle or something else cheap. Last quote I found it was upwards
of $250 for two tires mounted and balanced.

milesh

That sounds pretty cheap. I wanted E load rated 10 ply 16" tires for my
truck and they were about $145 each mounted and balanced. C rated tires
were closer to the price you paid. Depends on the brand but I prefer
Pirelli's or Michelins myself.