Tailshaft on 59 and 60 question

[Bruce Reynolds # 18992]

Gday all,

As you have no doubt been aware that I have been having vibration problems with the tailshaft in my 60 CDV, I find it is time to attack it from another direvtion.

Now, I have replaced the top ball joint, had the tailshaft out, new universals, balanced, straightened, and the centre bearing mount and bearing are good, and the front transmission mount is good, and I have performed the factory recommended modification to the centre bearing mounting location.  The car sits at the factory settings, and the lower control rubbers still appear okay, but if necessary, I will replace those.   But I still have the rotten vibration on take-off.

My request is that if anyone has either their car up on jacks, or has a tailshaft laying around, I would appreciate it if they could measure the number of degrees that the rear yoke is out of phase with the front yoke.

I have none here in Tasmania to compare with mine, and therefore, this request.

My rear shaft is between 5 and 7 degrees out of phase, ahead of the drive direction.   If it was the other way, then I could understand that the rubber tortional vibration damper has slipped, but everything appears to be undamaged in that area.

If you cant get an actual degree measurement, then just a sighting using straight edges will suffice.

Bruce,
The Tassie Devil(le),
60 CDV

P.S.   My hub caps arent falling off now, so that is one less thing to worry about.

[Steve #20480]

Bruce,
If you could tell me how to measure the degrees I will take a look at mine. Ive got a 59 Convertible, but the body is off the frame right now (In the middle of a frame-off restore). I too had my driveshaft redone, balanceing, etc. The frame; motor, trans,  etc. is all put back together, waiting for the body to get ready.I would me glad to help if I can.
Steve

[George]

Bruce, what was the factory recommended modification, on the centre bearing?
  The pinion angle adjustment on my 59 SDV is essential for vibration free running, I dont know if it the same for the 60.

[Bruce Reynolds # 18992]

Gday George,

I cant claim the credit for the following information as Ed Mobley obtained it after having a similar problem.

The modificaton entails slotting the centre bearing bolt holes in the chassis 1/8 to the right, and inserting a 1/8 shim under the mount.   The article actually says to slot the holes to the Passenger Side, but, as we from the other side, realise that some people dont know that some passengers sit on the other side).   It also goes to prove that Cadillac never made a factory built RHD Cadillac in 59 or 60.

This is described in the Cadillac Serviceman as a fix for tailshaft vibrations for the 59 and 60 Cadillacs.

I have performed the task, and it has done what it was intended to do, but I still have a vibration, but not as bad.

Buce,
The Tassie Devil(le),
60 CDV

[Bruce Reynolds # 18992]

Thanks for that Steve,

The best method is to have a proper inclinometer, but I dont have one of those, so I use the following method:

Use a small spirit level and place it on the outside and across the front yoke trunion end, and turn the shaft until the bubble is in the centre of the glass.

Then, without moving the shaft, go to the rear yoke, and check that in the same way to see if that is level.

If not, arm yourself with a simple geometry protractor from your old school days and place that on the yoke, then gradually bring the spirit level into the level position and read from the protractor, the number of degrees it is out of plumb.

You will soon see if it is level or not.   If not, then is the out of phasing towards the forward turning of the shaft, or on the trailing side.

It is easier to do the front and rear checking if the shaft is in the car, as it is impossible to see inside the X member.

Bruce,
The Tassie Devil(le),
60 CDV

[George]

The pinion angle can be altered using shims. The pinion angle can cause vibration. I have had no experience of this. I read about it in the 59 manual after I read you letter. Perhaps someone has done this.

[Ed Mobley]

As Bruce knows, mine is offset in the same fashion.  I think it was part of the design.  

There were a number of articles regarding tailshaft vibration in the Cadillac Serviceman and Cadillac even came out with a special tool to align the tail shaft.

Im wondering if one could take a drive shaft out of a 63 or 64 Cadillac which had double cardan joints.  Has anybody done this?  It looks like the pinion will have to be changed, but Im wondering if the frame would have to be modified to accomodate the larger double cardan joint.

Ed

[Bruce Reynolds # 18992]

Gday all and sundry,

Im bringing this back to the top, as I still require the following original information.

Bruce,
The Tassie Devil(le),
60 CDV

Gday all, As you have no doubt been aware that I have been having vibration problems with the tailshaft in my 60 CDV, I find it is time to attack it from another direvtion.

Now, I have replaced the top ball joint, had the tailshaft out, new universals, balanced, straightened, and the centre bearing mount and bearing are good, and the front transmission mount is good, and I have performed the factory recommended modification to the centre bearing mounting location.

The car sits at the factory settings, and the lower control rubbers still appear okay, but if necessary, I will replace those. But I still have the rotten vibration on take-off.

My request is that if anyone has either their car up on jacks, or has a tailshaft laying around, I would appreciate it if they could measure the number of degrees that the rear yoke is out of phase with the front yoke. I have none here in Tasmania to compare with mine, and therefore, this request.

My rear shaft is between 5 and 7 degrees out of phase, ahead of the drive direction. If it was the other way, then I could understand that the rubber tortional vibration damper has slipped, but everything appears to be undamaged in that area.

If you cant get an actual degree measurement, then just a sighting using straight edges will suffice.
Bruce,
The Tassie Devil(le),
60 CDV
P.S. My hub caps arent falling off now, so that is one less thing to worry about.

[JIM CLC # 15000]

05-10-05
Bruce, when you drive-off, have you checked your rear-view-mirrors to see if maybe the wifes favorite cat is behind the car.
No kidding, cats love to lay on the drive-line,but, when it starts to turn,reather then fall-off they tend to hang-on, there-by creating an out-of balance sisuration for a short while.
Reccommend you call the cat and feed it, so you can drive off, or,kick the side of the car as you get-in, to wake up the cat and maybe it will think it time to go potty and hop-off.
Good Luck, what ever the problem, Jim

[Bruce Reynolds # 18992]

Sorry Jim,

Nice try, but that wont work here.   The pet Rottweiller and Siberian Husky keep ALL cats well outside the boundaries.   There was a possum in the yard once, it had a lovely smile on its head, but the rest of it was six feet away, with nothing in between, but grass.

Bruce,
The Tassie Devil(le),
60 CDV

[Roger Zimmermann]

Bruce, do you still have vibrations? If I'm asking you it's because I have vibrations at about 50 to 55 mph with my Brougham. A friend of mine has also vibrations with his Brougham. He noticed also (like me) that the rear universal joint is not in phase with the front or middle one. We are wondering if this out of phase may have an influence with vibrations. From the theory, joints must be in phase to avoid vibrations. Maybe Cadillac had a different opinion at the time...

[The Tassie Devil(le)]

G'day Roger,

Sadly, I sold the car many years ago, and now I am enjoying my '72 Eldorado Convertible.

I never did get around to doing what my last thing was going to be, and that was replacing the rear tube with a solid tube, and putting the yokes into correct alignment.

The current owner hasn't complained about any vibrations, so I can only assume that he isn't worried about it.

But, as I said in my initial report, my vibrations only came on acceleration, at around 15 Mph.   Put the foot down hard, and no vibration.

Any vibration like you are referring to, usually sounds like tyre/s out of balance.

Now, I have some two-piece tainshafts in the garage, and will look at those tomorrow, and measure them to see if they are inline.   These shafts are from '63 Chevrolets, and have solid tubes.

I was always not confident with the out-of-alignment of the Cadillac shaft, but thought Cadillac engineers knew better than me.   A friend in California with a '60 Coupe measured his shaft and that had the same degrees out of alignment as mine.

Bruce.

[Roger Zimmermann]

Thanks for the quick answer Bruce! I'm also convinced that this out of alignment was correct however, it was probably perfect when the rubber was still flexible. With the age, the rubber is probably not doing his job properly...
Angles are also a factor with vibrations. I will play this year with washers under the transmission support and evaluate.

[The Tassie Devil(le)]

Don't forget that I mentioned that the rear yoke was out the number of degrees ahead of forward rotation.

The Rubber Sleeve in the shaft could not have moved that far forward even if it was worn out.   As for being worn out, I am pretty sure that it would have still been as good as the day it was built, internally, as any other shaft, similarly built, has always displayed good rubber internally when cut open.   The ones I have cut have been behind stronger engines than the '60 Cadillac.

Bruce.

[Roger Zimmermann]

Thanks for those precisions! If the rear joint is ahead, therefore it must be right. I will have to check it. If you found good rubber by cutting other drive shafts, I have no reason to worry about that.
Thanks again!

[Thor]

I recall from college kinematics that a drive shaft with a U-joint at each end behaves thusly:

No angle at joints = all parts rotate with the same constant velocity

As you add angle, the drive shaft has to speed up, then slow down to accommodate the U-joint constraints.  This cycle happens a few times (twice?) during one rotation of the input shaft at constant velocity.

At small angles, the delta V is small, but at Monster Truck angles, there is a lot of difference, hence more vibration.  Seems that the optimal arrangement would be to place the driveline in a straight line at the average axle height, or the height most often used.

Don't forget, there are apps for your phone that measure the angle of things to some degree of accuracy to the tenths...... we use this in running windlines for pipe organs and the results are good.  Tazmanian folks can make anything from scratch, including an adapter that fits on the tailshaft, or just put the phone right on the tailshaft flange and add 90 degrees - there's yer pinion angle.

My '60 Hearse has a periodic throbbing sound coming from the rear axle, but it'll get a good going-through with new wheel bearings and a rebuilt diff.  U-joints were done within the last 15 years.

Good luck Bruce!

Randy Bergum
26162

[The Tassie Devil(le)]

Took some pictures of the latest tailshaft I dissected and you will see that the end of the ring that is open to the air is showing signs of degradation, but apart from the first 3/16", it is like the day it was inserted.

Notice that the rubber is divided up into four segments, and the length of overall coverage is good.

This Tailshaft is from a local Ford LTD, and is 3 1/2" in Diameter, with the inner rear section being 2 3/4 utside Diameter.

I would love to see the way the pieces are pressed together, as it would need a lot of pressure to squeeze the sleeves into the outer tube.   I also noticed that the inner sections of the rubber is bonded to the inner tube.   This stops the rubber slipping on the shaft as the insertion takes place.

Now, as for the two-piece Chevrolet tailshaft, the universals are completely in alignment.

The last two pictures show the spacer I made for raising the centre bearing, and the wire is there to allow me to slip in into place, whilst the shaft is in place, and then I simply tied the end of the wire out of the way, for future operations.

As a word of warning, don't adjust too high, or to the side without manually turning the shaft, as the tolerances between the universal and the floor is sort of tight.

Bruce.

[russ austin]

Have you changed the trans tail shaft bushing?  Although unlikely in your situation, it cured my 55 mph vibration.

[Roger Zimmermann]

To Bruce:

Thank you for the pictures and description!

To Russ:

The transmission was overhauled some years ago by a transmission shop. Nowadays, I would do it myself! Therefore, I ignore if the bushing was replaced.

[The Tassie Devil(le)]

One thing I failed to mention is that I don't know what the internal construction of the Cadillac rubber-bushed tailshaft is, but I was surprised to find that the one I cut up had the four separate dampers within the length of the joint.

Would love to get a Cadillac shaft and do the same thing, but, alas, none down here to play with.

Bruce.