Twisted

I have been troubleshooting a rough idle since I bought my car. It feels like the car is shaking. I also get this strange vibe at 75 mph. I looked at my balancer, and noticed that it has a very slight wobble--slight enough that it could be my imagination--and that the rubber looks cracked and dryrotted. Can anyone tell me their experiences with bad HBs?

50Trippin

i don't believe you would have to be able to physically see it wobble. if the rubber has deteriorated it could be off balance and cause vibration.

Grimace5.0

Usual symptoms include whacked out timing ( if you've tried to time it lately ) what happens is the outer ring will "spin" because the rubber deteriorates.

Grimace5.0

I read your vibe problems in another thread.

Check
the wheel bearings
Clock the driveshaft..you just had it off to put gears in.
U-joints? When was the last time they were changed?
Loose lug?
Motor mounts?

Twisted

I don't think it's that bad yet, Grimace. I was able to set the timing properly, and it seems pretty accurate. 50Trippin, that's what I'm thinking--that it's just bad enough to cause some mild symptoms. I may have my mechanic look at it, and see what he thinks. Is there any harm that could come of me letting it go for a while, since the outer ring is not spinning?

Twisted

Thanks Grim. I have no idea when the U-joints were changed. How do I check them? The motor mounts and rear axle bearings have been changed. Not sure about the front bearings though. By the way, what does it mean to clock the driveshaft? Incidentally, when it first happened, my instincts told me the vibe was coming from the driveshaft. At any rate, thanks again.

Grimace5.0

1. drink a beer
2. crawl under the back of the car.
3. grab the driveshaft side of the u-joint yoke with one hand, with the other hand grab the other side of the u-joint. Rock it back and forth, like giving a "indian burn" as a child. If there is slop or movement replace it.
4. crawl out from under the car.
5. drink a beer and figure out what your going to do.

Remove the driveshaft bolts and turn the driveshaft 1/4 turn on the pinion yoke.

Twisted

Your making me want to put down the ganja and drink a beer, Grim. At any rate, thanks for the info. One question: What is the purpose of clocking the driveshaft?

P Zero

LOL Grim, great advice......Get drunk then go work on your car.AHHAHAHHAHHA.
Anyway, this is how you tell where your vibe is comin from. When youre going your 75mph or whenever the vibe is, if the steering wheel is shaking, its coming from the front end. Check the tires make sure theyre not seperated and that theyre not outta balance. Then check wheel bearing tightness, then check for a seized caliper, shake down the front end make sure tie-rods and tie rod ends arent loose and so on ruling everything out.
If it shakes your *** and feet, then its comin from the rear of the vehicle, it could be your drive shaft, or your back tires out of balance or even one of the axles being bent and causing a wobble effect. If you do suspect the driveshaft, take it out and have it balanced, it shouldnt be anymore than like 75 bux or so. Id recommend that for anyone with an older car.
As for the harmonic balancer, if the outer ring spun how could you ever check your timing? Isnt that where the marks are? I spun the outer ring on an old probe GT I had, it made it shake at idle, bad enough to where you could see the passenger seat vibrating. Replaced the balancer, ran great until I spun it again, stupid *** design on that car, the outer ring of the balancer drives the serp. belt. A factory replacement one should be relatively cheap. If you go the fluidamper route theyre a wee bit more, but theyre WAY better than stock.
-P.

XPBaller

Well im in the same boat as you. At 1k rpm it gets a bad shake in the wheel and shifter, after 1k it goes away, then it makes a hard return at 4500+. I bought a new HB, ill let you know if it works out.