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1957 differential / rear end vibration

Started by rich neary, August 25, 2014, 08:38:21 PM

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rich neary

My 1957 Series Sixty Fleetwood has developed an annoying vibration.  I and several professionals have diagnosed it as driveline/rear end. It is most noticeable at 60-65 mph.
I've tried to deal with it logically and not simply throw parts and dollars at it but so far I'm not having much luck and seem to have ended up doing just that.
Axle bearings, universal joints, driveshaft center bearing rubber mounts (bearing good), had driveshaft angles checked and driveshaft balanced, had wheels/tires balanced on newest "road force" equipment. and tomorrow will try new brake drums.
I had a conversation with another 57 owner today and was told he had the same experience and is in the process of changing complete rear end housing and diff.

I'll change the entire rear if necessary but before I do I'd like to pick your collective brains.
Has anyone else experienced similar issue, and have you found a solution or suggestion?
Any and all help appreciated.
Thanks
Rich


Rich Neary
Statesville, NC

1957 Series 60 Fleetwood
2013 CTS
1955 Jaguar XK140MC  FHC
1965 Deville Convertible
1998 Jaguar XK8 Coupe

Dave Shepherd

First of all these cars did not do this new. So what changed? Can we assume this is felt thru the floors and body.can you get this condition running the car jacked from the axle housing at the same speed? If so look closely at the wheels for axial and radial runout. Look athe driveshaft for any runout. We encounter this a lot in my resto shop and pinpointing the source can be difficult.

Jon S

Do you hear a "thump thump" sound when traveling 20 MPH along side of parked cars?  If so, I may have your answer.
Jon

1958 Cadillac Sedan De Ville
1973 Lincoln Continental Coupe
1981 Corvette
2004 Mustang GT

dplotkin

56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

Roger Zimmermann

Try also to change the angle between the transmission and the drive shaft by adding large washers between the transmission cushion and the support attached to the frame. With age, the rear cushion may have colapsed.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

Philippe M. Ruel

The angles between transmission and drive shaft and between drive shaft and rear axle input shaft are supposed to be dealt with by U-joints - within some limits of course.

The most important angle is the one between transmission output shaft and rear axle input/pinion shaft. It should be as close to zero as possible.

A collapsed trans mount or sagging rear leaf springs may change all this and produce vibrations.

Some info about driveline phasing :
https://www.youtube.com/watch?v=DDmz0tibVGM
1952 60 Special in France.

Roger Zimmermann

Philippe, don't forget that drive shafts from 1957 and later are in two pieces with a central bearing. I had a similar problem with my '57 Brougham; when I added some washer between frame and transmission, the problem went away. Another point: if the angle between 2 elements is zero or near zero, the U-joint will be destroyed rather quickly, it was what I experienced on the Brougham: the U-joint lasted maybe 5000 km because the angle was zero. There must be some angle to let the U-joint to work properly.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

dplotkin

#7
I was not trying to be a wise guy when I asked about your tires and/or wheels. I hope that was the first thing you checked as it is the most likely and easiest thing to fix. I own 8 cars and have learned this the hard way when chasing vibrations. A tire can "balance" OK and still vibrate. Have you moved them around the car to see if the vibration moves with them? Have you tried another set?

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

Dan LeBlanc

It appears as if one of the things he has had done is road-force balancing.  That means a roller exerts approximately 1400lbs pressure on a tire while it is spun up on the balancer.  Sensors in the roller will tell you if the tire is wobbling or hopping, will advise the installer to match the high spot on a tire to the low spot on the rim, and suggest the optimal mounting position on the car for that particular wheel/tire combination.

I had this done with my bias ply tires as they were shimmying quite badly above 55mph.  Now the 61 rides as smooth as my '04 deVille.  The road force balancing would've ruled out a bad tire, rim, or both for him.

On the way to the GN, I noticed a bad driveline vibration at 32-45mph.  I knew the tires, u-joints, etc, were good.  I read a post somewhere about the rear transmission mount collapsing.  What I did was jack up the rear of my transmission with it still bolted in place and I got about 1/2" movement out of it.  I shimmed it at that raised position and the driveline is now silent.  Yes, the car has only 21xxx miles on it, however, that rubber is still over 50 years old.  The mount had indeed collapsed.

I have an NOS one waiting to go in this winter when the car comes out of service and it is stormy out with nothing better to do.

The attached may also help you.

Dan LeBlanc
1977 Lincoln Continental Town Car

Walter Youshock

I had my tires and rims balanced on the car with each wheel marked as to where it belongs on the car and a corresponding mark on one wheel stud.  It helped a lot.  But, I can never rotate the wheels without going through the process again.
CLC #11959 (Life)
1957 Coupe deVille
1991 Brougham