Drive Shaft: Vibration/driveshaft

[MPallock]

Gentlemen:

I am sure this has been covered before however. On my 54 Commander coupe when starting from a dead stop there is a vibration/shimmy underneath the center of the car until the car gets moving. I am almost certain it is the driveshaft. I have just put on new universals and a new bearing in the support and it did not help. This is especially noticeable when going up a slight grade or hill. My question is this, where should the support bushings be positioned in the support? Mine are all the way to one end and actually may not be in the round cutouts also which set of holes should the support ne bolted to on the cross member ? if refering to the book mine are in the #2 which is for a 116"WB LHC. Is this correct or does it matter that much?

Thanks: Mark

[junior]

Is your car stock or modified...mine is modified and I have spent a great deal of time chasing the same problem but many of my solutions would apply to a modified drivetrain only. I have solved a lot of problems but still have some minor vibrations. Start with placing the steady bearing in the holes the factory service manual dictates. If you still have problems check/replace the tranny mounts. My drive shaft (rear one) was slightly bent and needed to be straightened and rebalanced. The support bearing bushings/cushions were slightly loose and needed to be replaced as well. Other than that, most of my problems were related to incorrect driveline geometry. Still have 2 degree rearend shims I want to try, and will be replacing engine mount cushions with softer 57 Chev OEM style ones, but once again this only applies to my particular problem. If this doesn't solve my problem I will look into a CV joint on the front shaft like the one on Pat Dilling's car, but I will wait until I install the 5speed that has been sitting under my work bench for the 5 last years. Good luck, let the rest of us know when you find your solution(s). Junior.



54 Champ C5 Hamilton car. In my family since 1958.

[Tom Bredehoft]

I have just put on new universals and a new bearing in the support and it did not help.

First thing I'd do is verify that the center mount is in the correct holes. You need the shop manual for that. There are four places it could be, three are wrong. When I first got my Coupe from the folks who did the Mechanical Work, (Well known Studebaker folks) a pair of holes had been drilled half way between the top and bottom pairs, and it was mounted there. I put it in the right holes, (don't remember which, now) and it quieted right down.

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Tom Bredehoft
'53 Commander Coupe (since 1959)
'55 President (6H Y6) State Sedan
....On the road, again....
'05 Legacy Ltd Wagon
All Indiana built cars

[MPallock]

should the bushings be in the center of the support?

[Tom Bredehoft]

Left hand drive, they should be on the right side of the car. Not sure which, top or bottom, goes with the 6 or 8.

[img=left]http://www.alink.com/personal/tbredehoft/Avatar1.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe (since 1959)
'55 President (6H Y6) State Sedan
....On the road, again....
'05 Legacy Ltd Wagon
All Indiana built cars

[MPallock]

I have the book that shows which holes the support goes in but what I am not sure is how the bushings seat in the support

[StudeRich]

quote:Originally posted by MPallock

I have the book that shows which holes the support goes in but what I am not sure is how the bushings seat in the support

The driveshaft support bearing bracket, should sit in the CENTER of the two small rubber bushings on the cross member. [^]

StudeRich

[55studeman]

Whenever I have the drive line out of a care to do work, like changing out the universal joints or center bearing I go ahead and get the driveline balanced. It's very important to do and many things happen over the decades our cars have been around. Each time I've had it done there were new weights welded on, so it was needed and this was one cars that didn't have any significant vibration problems to begin with. So I would highly recommend getting it done. There's usually 1 or 2 shops in big cities that do strictly drivelines -especially in industrial areas because they do a lot of Big truck drivelines, it's big business.

good luck

Best Regards,
Eric West
"The Speedster Kid"
Sunny Northern California
Where the roads don't freeze over and the heat doesn't kill you.
And an open road is yours to have -only during non-commute rush hours 9am-4pm and 7pm to 7am (Ha, ha, ha)
55 Speedster "Lemon/Lime" (Beautiful)
55 President State Sedan (Rusty original, but runs great and reliable)

[leyrret]

As stupid as it might sound stiffer rear suspension might help. I find that under acceleration the axle windup
with weight shift to rear changes the geometry to the point it vibrates. If you set rear pinion axle allowing for windup under hard acceleration by degree or two may help.

[GEEMAC]

Had a slight vibe in my 57 GH just at a certain speed, chased this sucker for a long time, drive shaft, mts, u joints, finaly found a slightly bent rear axle,installed a used one i had laying around and solved the problem, what a relief!MAC

[Dwain G.]

Your car is supposed to use the number 1 mounting holes.
As you assemble the front driveshaft, make sure the flange on the slip yoke is aligned exactly with the flange on the rear of the transmission. This 'phasing' is very important.

[MPallock]

Ok here is an update on what has been done today. Had drive shaft balanced and they phased the drive shafts. Centered the bushings in the support and verified that I am in the #1 holes on the support. None of this helped.
I am thinking next maybe stiffer shocks? or pulling the rear hubs off and see if something is not quite right
Thanks for all your help. I will let you know what happens.

Mark

[Dan Timberlake]

When a Cardan type u-joint transmits torque while operating at an angle it creates a "secondary couple" . I think of it as the 2 shafts trying to return to a straight line position, with a pulsing motion. More angle, or more torque ( lots of throttle, in a low gear) and more secondary couple results. I don't have the factory specs for the recommended angle of the shafts at the center support bearing, but think shimming the trans, the center support bearing, or diff to make the front and rear d/shafts more in line would help.

http://www.airridetalk.com/images/stories/u_joint/Angles.gif

Some non-Stude folks have had success moving the center support to make the front shaft inlne with the trans, then angle shim the rear axle for equal angles at the front and rear of the rear d/shaft.

http://www.rodandcustommagazine.com/techarticles/0608rc_driveshaft_tech/driveshaft_support.html

Did you remove the driveshaft? Did all the u-joints move very freely? I've had tight u-joints in non-Studebakers with 2 piece shafts shudder badly at low speed.

[Dwain G.]

Verify that the shop aligned the slip joint yoke with the transmission yoke, not the differential yoke. Check wheel and tire run out, both laterally and radially. Measure all the u-joint angles and see what you have.

[ROADRACELARK]

I didn't see you mention wheather this is an automatic transmission or a manual. If it's a manual, check the clutch. How old? Is it in proper adjustment? (according to shop manual specs) "Clutch chatter" is very prevelant in older cars. An engine oil leak can allow oil to find its way inside the bell housing and possibly find its way onto the clutch mechanisim. BTDT, just a thought.

Dan Miller
Auburn, GA

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Road Racers turn left AND right.