I'm getting a vibration at 55-60 mph in my 58 Impala. The first thing I did was balance the wheels and it made no difference. The car has been lowered 3 inches on all 4 corners and I was thinking it might be the driveshaft because of the new angle? Has anyone had a similar experience?? Need some help!
That's certainly a good theory. First, did you get the wheels and tires road force balanced or just have the kid at Mavis spin them on the machine? There is a significant difference. Have you checked the roundness of the tires themselves? Unfortunately, some brands (cough:Coker:cough) are notorious for selling tires that are about as round as an octagon. The tires may need to be shaved to true them up. Anecdotally, I had a terrible vibration in my 57 Ford and always thought it was because of lousy suspension. I took the Coker Classics off it and put Auburns on and the vibration went away. As for your driveline angle, that could certainly be the culprit as well. Take guessing out of it. Jack the car up and put jack stands under the rear so it's holding weight as if it were at ride height. Get an angle finder and measure the angle of the engine, trans, and even take a measurement off the flat spot on the slip yoke of the driveshaft. Then measure the angle of the rear. They should be parallel. If they are not, then you'll need to adjust your pinion angle so that they match.
Was the drive shaft shortened after lowering? When you lower it it should shove the drive shaft into the trans. If the yoke is bottomed on the output shaft it will eventually destroy the trans. Check the slip yoke at ride height.
lowering the 58 that much will change the pinion angle if nothing else has been modified. So get yourself an angle gauge and do some checking.
On a car like that that has a 2 pc driveshaft, you need to jack the car up and support the rear axle on stands to simulate the car sitting on its wheels. then loosen the 2 bolds that hold the center driveshaft support to the frame, Did the support slide forward? it probably did. tighten the bolts and take it for a ride
What I would do is drive it at the vibration speed and note the engine rpm. With the vehicle stopped and transmission in neutral, rev the engine to the same rpm. If the vibration is still there, the problem is engine/flywheel related. If it isn't, the vibration is driveline/wheel end related. That test cuts your list of possiblilities in half. If you determine that the problem is driveline/wheel end, the next thing to do is to try and determine the frequency of the vibration. Wheel problems tend to vibrate once per revolution. Driveline problems vibrate 3 - 4 times faster; they feel more like a buzzing. I like to get the vehicle up on sturdy stands with the rear axle supporting the vehicle weight, not hanging down, and run it in gear to see if you can duplicate the vibration. You may have to back off the rear brakes to get both wheels turning. Many times you can now see what it is that is vibrating. If it doesn't vibrate on stands, but still vibrates on the road; the problem is in the front wheels. Again you cut your list of possibilities in half.
Another thing to look at is where you feel the vibration, If you feel it in the steering wheel the place to start looking is the front wheels and suspension. If you feel it in the seat of your pants, start with the driveline and rear suspension.
On a 2-piece driveshaft , the first section is locked between the trans & center carrier , there is no forward & back movement , that takes place at the slip-joint b behind the center carrier bearing . IME most "55mph" vibrations are caused by wheel tire out of balance .
Unfortunately, some brands (cough:Coker:cough) are notorious for selling tires that are about as round as an octagon. I second that! Four new Croker tires and the Wobble de la muerte at fifty. Drove forty miles to have them road forced balanced. All four were unable to be balanced but one called for just over a pound of weight. Imagine that flying off at speed. Coker did replace all and road forced balanced them before shipping.
this is incorrect. the slip yoke on these is at the transmission. there is no slip yoke after the carrier bearing. for and aft movement is handled by deflection in the rubber encasing the carrier bearing. This is why it is important that the carrier bearing bolts be tightened when the weight of the car is on the rear axle
When I was 20 I told my girlfriend's dad I'd help him adjust the valves on his Buick V8 to try to get rid of a ticking sound. A few days later he told me the dealer said they had to change the cam and lifters. Since then I've had enough mortifying "Gee, I know the answer to that" moments over the years that I now generally take a peek in the manual or ask Google before embarassing my self, again. https://www.npr.org/2017/04/04/522581148/hemingway-didnt-say-that-and-neither-did-twain-or-kafka
If you measure the driveline angle and it's now off from lowering it you can fix it. You should be able to add or remove the shims on the torque arm (between the arm and body). Also I haven't seen to many X frames (that have been lowered) that don't need some driveshaft adjustment. I usually add a slip yoke in the rear shaft, this puts the carrier in the center of the slots, less pressure on the carrier rubber and puts the yoke in the proper 3/4"-1" out of the transmission.
Hello, When we first took the new 58 Impala to the drags, the speedometer pegged at the far right and stayed there until the timed race was over. After a few runs, there were a few shakes while slowing down. Then, on the highway, we noticed a definite shake going past 50. So, we, too, went to the tire shop for a balancing of all 4 wheels. The height of the suspension did not make a difference if it is the tires or wheels. Balancing is what we all think of for the first thing. But, when we went to a recommended tire and wheel alignment guy in Culver City, he knew what to do. He sent us to a tire shaver. That guy’s job was to shave the rubber off until the tire was perfectly round. Once that was done, the tire guy now could do a good wheel balance and set up his alignment. Don’t be sad that there was a ton of rubber on the tire shaving shop work place. Tires are supposed to be round, but for the most part, they are. But, every one is not perfectly round. So, the tire shaver is necessary. Just a wheel balance won’t fix the problem. Matching wheels and tires help. Now, at least the tires are round and the guy started on his wheel alignment and balancing. Jnaki After the whole process was done, it ran like a cotton towel sliding over a waxed hood as if it was in a car show display set up process. No hinderances, bumps, shakes or pulling to one side or the other. It became a “no hands” straight line driving on a flat coastal highway, or freeway. Thanks to @themoose On the other hand, when new Buick Skylark Wire Wheels were added, modifications took place and again, the new tires got the shaving process, THEN, a complete wheel balance and alignment for perfect running on all sorts of highways. It was not just a wheel alignment place. The guy was an expert and did all of our family cars from Buick sedans to the Impala to the 40 Ford Sedan Delivery and finally the 65 El Camino. All got the tire shaving process first before any other work was done on the front end of any of our cars. Note: No one likes seeing shaved rubber on the floor coming from your tires. But, it will work best if the tires are round. With the now “round” tires, it got better wear, no shimmy or shakes at any speed and lasted longer than our old tires. There must be a place like the ones we used out here on the west coast somewhere in your area. All of our cars, the Flathead 40 Ford Sedan Delivery, the 65 El Camino (two sets of tires,) and our 327 powered 40 Ford Sedan Delivery all had the tire shaving done and then a great balancing + wheel alignment. Out of the 4 cars, the 327 powered sedan delivery was a project car and needed more extensive front end work and safety protocols. The El Camino had new wider tires and it too had the shakes, so a pile of rubber later, our front end specialist took the balance and alignment to a total of 50k miles before another set was done. Before one goes on a witch hunt for the technical specs being the problem, check out the balancing on tire shaved round tires. For us, something as simple as tire shaving made the tires round and the balancing was done, but minimal. Your balancing machine will look for where the weights go and that may be the cause. Hopefully you did not use a bubble balancer. Look up “Tire shaving” and you should find one close to where you live. The find a good tire and wheel alignment/balance shop to finalize the adjustments. YRMV
Lowered a ride with a 2 piece drive shaft a while back. Was a 6 inch drop. We had to raise the center bearing support to correct the angles
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