chassis vibration

[uncltodd]

Okay, BDR build #139 suspension.

I THINK it's BMW 325. Can't confirm.

On decelleration, at highway speed, total chassis vibration.

Just did a really tight wheel balance, the Nittos were a little off, that killed about half the vibration.

My ace mechanics report that the driveshaft and U-joints are clean and cool, ready to rock.

The steering wheel tries to dance in my hand over 35 MPH, but ONLY when I decellerate. I'm talking 1/2 inch dance.

Full 4-wheel alignment tomorrow, with new Hunter machine, operator has 26 years experience. Knows Beemers.

Before I beat my kidneys to death on the so-called "highway" to Durant, 30 miles, any suggestions?

UT

[Bob In Ct]

Does "decellerate" translate into step on the brake?

Bob

[terry251]

UT, any chance the off-roading experience toasted one of the motor mounts?

Terry

[blykins]

UT.....check engine and tranny mounts.....

[uncltodd]

No braking, just back off the throttle.

Engine and tranny mounts?

Never thought of that!

Glad I posted!

Thanks, y'all.

UT

[uncltodd]

Nope, not engine mounts or tranny mounts.

My mechaniciens were incensed that I would ask them such a thing.

Blew off the alignment, tire shop called and said the alignment machine had a stroke and the Hunter Doctor was on the way.

Maybe tomorrow.

There is a curse on this car.

I'm dealing with it.

UT

[LwCwb]

Don't fret UT, you'll get everyting buttoned down before too long.

[392cobra]

UT,
It has most likely already been checked but anyway.....check the set screws that hold the intermediate steering shaft .

[uncltodd]

Fred- only vibrates when backing off the throttle, speed doesn't seem to make any difference (over 50 mph)

Braking, accellerating, no vibes!

Even after a high-speed wheel balance, the steering wheel still does a little dance, both of my young "chauffeurs" noticed it today.

I swear it acts like a bad U-joint or an out-of balance driveshaft, but they all checked out fine. The "bad vibes" seem more in my shoulders since the new wheel balance, not so much in my butt.

If 30 miles of Oklahoma highways don't kill me tomorrow, I'll report back.

Intermediate steering shaft? We'll look, I promise.

Thank all of you.

UT

[Doug I]

Hey UT

while you're under the car check the tie-rods and their joints (particularly cracked or compressed bushings in the joints). Check the anchor points for the steering and front suspension. Look for things like cracked paint or a mark showing where something has moved from where it normally is. Something might have got knocked loose or shifted slightly when you tried fencing.

Now that it's been a while since since your 'event' a few things will have had tme to become a little more visable than they were when it all happened.

If something shifted a little it could get loose when it isn't loaded (as in a coast off the gas) and send a shimmy up the steering wheel.

Good luck (it'll make a change )

regards
Doug I

[uncltodd]

Doug, you keep posting good advice like that and I SWEAR I'm gonna start eating crawfish and cooking "dirty rice."

Thanks, Mano.

UT

[BMK]

If all else fails. look for dirt, grass, fencing wire, posts, gates or rails..

Sorry but had too..

[BDRCobra]

Open your hood and while you are looking at your steering column turn your steering wheel. There should be no play. If you move the steering wheel a mm than you should see your tire move 1 mm. As the previous poster said check where the steering shaft slides into the steering column. There are two allen head screws and nuts. Also check where the lower steering wheel u-joint goes into the steering box. I found the connection there to be loose. Turn your steering wheel so you have easy access to the allen head bolt. It is very easy to do, everything should turn at the same time with no play. If your rack is loose than I beleive there is an adjustment on the rack where you loosen a large nut and then adjust the allen head screw in the middle.

[Doug I]

Come on over Todd and I'll introduce you to Boudin (pronounced boodan). I reckon we could have a Crawfish boil while we're at it.

Have a good one

Doug

[Doug I]

Hey Bernie

From the photos I think he's already found some of those .......

[Toby]

UT,

Directions for removing curse from car:

Take one fresh chicken foot (from dominecker rooster if possible, but no banty's) and dip in two parts oil one part your own blood. Write on the bonnet "MY COBRA LOVES ME" exactly 13 times. Turn around twice and spit on a rock. Curse will be lifted. p.s. Stay away from one legged chicken!!

just tryin' to cheer ya' up man.

Toby

[John A. Simpson]

Todd

I've had a couple of different things cause the same problem you're having, back off the throttle and the steering wheel shimmies back and forth maybe an inch or so. In my case seemed worse about 45 mph. The first time was when too much grease was put in a front ball joint (not by me) and excess grease dripped on the wheel throwing off the balance, most likely not your problem I would assume your tire shop would make sure the wheel was clean before balancing. The other time we suspected a bent wheel, which it could be, but it turned out to be a crooked belt in the tire itself. The tires balanced fine but had the same shimmy you describe. We even changed wheels ( same tires ) but as soon as I switched the tires themselves the problem went away.


John

[Cashburn]

John offers great advice. Due to these cars being extremely light they are more prone to tire defects. We have seen it before, mostly with 15" tires. Seems some manufacturers are using really old molds since 15" is relatively old tech. And in some cases they are a 2 piece mold which does not provide a perfect round everytime. Since the cars are so light and most guys inflate them all the way there is no give to smooth out the ride.

If you can borrow a set of used tires it might be worth the attempt.