vibration

[4tford]

Trying to solve a vibration on my 53. Has a broken driver side motor mount. A lot of movement when I twist the drive shaft. Have ordered new motor mounts and universals and they will be changed as will rear shocks as soon as parts arrive.. How much movement is normal in a drive shaft.

[JWL]

Well, it depends on where the movement originates. If there is universal joint "slack" that is bad. If the combination of ring to pinion, differential gears and axle splines to axle gears are all combined it can be substantial. If it is clearance between only the pinion and ring gears there should be little.

A more clearly defined question might elicit a better response.

[rotorwrench]

Good U-joints should have little or no play. There is backlash in the rear axle gears that will allow some movement but not a lot. There should be no shake in the rear axle pinion at all. Movement on the transmission end depends of whether it is a manual transmission or an automatic. On a manual transmission, there would be some gear backlash depending on what gear was selected or whether it is in neutral or not. High gear should have the least since it is 1:1 through the synchronizer assembly. An overdrive trans will freewheel in one direction if the car in not shifted into reverse or the overdrive is locked out with the control knob. The automatics with the park pawl locked in usually don't have much play when you try to rotate the drive shaft but they may have some if the car is on a level surface.

[4tford]

The car is 3 speed standard trans. Motor mounts need to be replaced as one is broke. Will have universals and rear shocks done as soon as parts get here. Only had the car 2 weeks and expect some issues. Car seems to have high rpm at 60 mph so may look at changing rear gears this winter. I have a feeling it is more than universals. Will know more end of next week.

[JSeery]

It is hard to know the RPM by ear, might be a good idea to check the RPM and also determine the current rear end gear. There are several fairly simple ways to check the gear ratios.

[JWL]

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Check the transmission/driveshaft yoke where it fits over the splines of the tailshaft. These can be the source of vibration when the outside diameter becomes worn and the tailhousing bushing is also chewed out.

[JAKEFORD]

I had soft oil soaked and rotted mounts on my old 53. One day they both let go. The engine fell forward and the fan got the rad.

[Frank Miller]

Might try balancing the tires also. Check that rims run true. If the car has sat for a period of time you may have "flat spots" in the tires. Those will sometimes work themselves out.

[APDAVE]

I had a belt break on my 50's right tire, shook the whole car at 30 mph! Dave

[4tford]

Update on vibration. Changed front and rear shocks to improve ride. No improvement on vibration. Next we replaced both motor mounts as one was broke, checked yokes and replaced universals, also removed the 2" lowering blocks. Vibration got very much worse. Today the front bushings on the rear springs were replaced as right side was missing. Big improvement. Went back and rotated rear drive-shaft yoke 180 degrees. Again improvement. Balanced tires and not much better as only one tire was a little out. Vibration was previously VERY strong. Now it is still quite noticeable to driver but reduced quite a bit and very steady when I hit 30mph or more. Stays the same when I push in the clutch and coast. Shop says the front end is tight and I have very little steering play. I think trans syncro is due for replacement this winter as I must be cautious shifting up from first to second and has popped out of second twice. I don't know where to turn from here. Ideas???

[Marv]

Sounds to me, like the drive shaft is bent or pinion bearing bad. If you have radial tires, a damaged one will also do that.

[4tford]

Well finally some good news. Major vibration is gone. Last night I had a strong feeling that the vibration was very different from when I started. Not sure how to describe it but to say the first vibration was strong and varied depending on of accelerating or decelerating, clunking on corners etc. The new vibration after changing all the parts was very steady. Thinking maybe something to do with the trans shaft I crawled under the car in neutral and tried to move the trans. What I found was a 1/4" of side to side movement on the front universal. Put on the hoist in a shop and found the inside retainer clip was loose and not in the groove. They pressed in the caps and re-installed the clip and 99% of the vibration is gone. 70 mph and she purrrrrs. The 1% left can be attributed to the spongy old rubber in the trans mount. Very happy camper now. Thanks for all the advice guys.

[Bulligen]

Yup, I filed and trimmed my springs and added grease, What a difference!!