68 Sedan Deville Driveshaft removal

[Wooly15]

I'm trying to remove my driveshaft to replace u-joints and cannot get it out. With all four bolts removed from the diff flange, the shaft rotates freely, but won't come down. It seems it needs to come forward toward the trans to clear something, but there's no room to move it forward into the trans. Any ideas/tips? Do i need to pull the rear end back? Thought I'd mention, i have the single price shaft with the double cardan joints on both ends. 

[Marty Roth]

Is the car sitting its tires, or do you have the chassis sitting on jack stands with the rear axle hanging by the suspension? If the latter, you should have additional length to be able to move the driveshaft forward to have the U-Joint/CV-Joint clear the differential?

 

Also, is there a center support bearing? If so, be sure it is unbolted  and free

 

Edited January 8, 2018 by Marty Roth (see edit history)

[Wooly15]

I had only one side on a jack stand. Let me try both sides to get the entire rear hanging. Good tip. Also, there's no center support.

Thanks!

[retiredmechanic74]

The rear axle has to be hanging down to remove the drive shaft. (used to be a Cadillac mechanic) Otherwise I't like trying to stuff marshmallows into a biggie bank. Are you familiar with replacing the universal joints on that type of drive shaft?? If not your going to have something less then fun. The joints are spring loaded and the universal cups are held in place with moldent  plastic. 

[Wooly15]

I'm not going to attempt doing the joints myself. I'm dropping it off at a driveline shop nearby. On that note, can you replace them with off the shelf u joints or do i need special ones? 

[Wooly15]

Update: jacking up both sides worked, thank you! The joints look new and have plenty of spring. The reason why I'm doing this, is to track down a driveline vibration. A balance and new shocks didn't help. Maybe the shaft itself is out of kilter. 

[Marty Roth]

Wooly15,

 

Glad to see that my suggestion solved your problem!

That is the benefit of OUR FORUM - many of us have "Been There Before", and sometimes have learned through experience.

 

If all else fails, it also helps to look at a Shop Manual, Motors Manual, etc...

 

Good luck with your project - is it possible that you may have a tire/rim imbalance? ... or possibly have end-play in the transmission output shaft?

[Wooly15]

The trans is freshly rebuilt, so checking that will be my last resort. The wheels were recently balanced but I may try again if the u-joints and drive shaft balance doesn't solve it.  Again, thank you for the help with this. 

[Wooly15]

Wasn't the drive shaft or u-joints. Going to try a more reputable shop to get a good balance done. 

[retiredmechanic74]

Back in those days we mechanics had access to on car balancing that way everything got balanced, rear brake drums, front drums and rotors and anything else. If you can find someone that still has that equipment that would be the way I would go.  

[Marty Roth]

On 1/22/2018 at 8:24 AM, retiredmechanic74 said:

Back in those days we mechanics had access to on car balancing that way everything got balanced, rear brake drums, front drums and rotors and anything else. If you can find someone that still has that equipment that would be the way I would go.  

 

Back in the day we used HUNTER on-car balancing uit 

It looked like a big Vacuum cleaner which rubbed against the tire and spun the entire rotating assembly.

There was a large metal disk which mounted kike a hub cap/wheel cover, and had several central rotating knobs to set the weight amounts.

I've forgotten how to use it, but it did compensate for more than just the wheel & tire.

We used it on our 1967 Citroen DS-21 Pallas because oher balance equipment would not accept a wheel which had no center hole.

[retiredmechanic74]

1 hour ago, Marty Roth said:

 

Back in the day we used HUNTER on-car balancing uit 

It looked like a big Vacuum cleaner which rubbed against the tire and spun the entire rotating assembly.

There was a large metal disk which mounted kike a hub cap/wheel cover, and had several central rotating knobs to set the weight amounts.

I've forgotten how to use it, but it did compensate for more than just the wheel & tire.

We used it on our 1967 Citroen DS-21 Pallas because oher balance equipment would not accept a wheel which had no center hole.

That's the same system I used at the dealership I worked at. When the system was replaced with off car balancing I bought the old system and for a number of years I used it in my shops. I let my brother take it and without my brother knowing it his son sold it.

[Wooly15]

Just an update to the thread. I had another shop balance the wheels. Nothing looked too far out of whack and they all balanced, but the shake is still there. One of the wheels looked slightly out of round on the machine but still balanced. I wonder if it could be bent just enough to cause a shake at 50-60mph.  

[retiredmechanic74]

1 hour ago, Wooly15 said:

Just an update to the thread. I had another shop balance the wheels. Nothing looked too far out of whack and they all balanced, but the shake is still there. One of the wheels looked slightly out of round on the machine but still balanced. I wonder if it could be bent just enough to cause a shake at 50-60mph.  

Generally a bent wheel will cause a dancing effect at very low speeds and straiten out as speed increases. Pay close attention to the vibration as to what it is effecting. If you feel it in the steering wheel  the problem is in the front. If you feel it in the floorboards or seat it is in the rear. One thing that can cause it is a weight that has broken off the brake drum. During those years I ran across that a number of times. 

[Ronnie]

On 1/18/2018 at 12:39 PM, Wooly15 said:

Wasn't the drive shaft or u-joints. Going to try a more reputable shop to get a good balance done. 

 

Did you check for a worn tailshaft bushing where the driveshaft slides in?

[Marty Roth]

Years ago I used a "Hunter" system which balanced the entire rotating assembly on the car, including the brake drum/rotor, and axle.

Those older units may be hard to find, but work well

[Wooly15]

I didn't check the tail shaft bushing. It has a rebuilt trans and driveshaft, so I just assumed it's good. Wouldn't that be noticeable at all speeds? I guess i will try and find someone that can balance brake rotors and drums. 

[retiredmechanic74]

On 1/28/2018 at 11:23 AM, Wooly15 said:

I didn't check the tail shaft bushing. It has a rebuilt trans and driveshaft, so I just assumed it's good. Wouldn't that be noticeable at all speeds? I guess i will try and find someone that can balance brake rotors and drums. 

I was just thinking, who rebuilt the driveshaft? The constant velocity joints have a ball and socket between the two universal joints and they are spring loaded. Care has to be given to the wear of those parts. With the shaft removed from the car the joints should snap back and forth when moved. You may have a ball and socket worn out, scored or the springs are missing or broken. Just a thought.

[Wooly15]

It was rebuilt then reinspected/balanced by a reputable shop locally. He checked the joints and they both had lots of spring tension. I think I may change the rear drums with new and see what happens. That' the least expensive and easiest next step.

[Wooly15]

New drums are arriving today, and I have a question about the shoes. They'e been on the car less than a year with not many miles. Do they need to be replaced along with the drums?. I know when doing new shoes, you should turn the drums so the surfaces are fresh, but I didn't know if the relatively new shoes would be ok. Wouldn't they just wear to the new drums?

[retiredmechanic74]

1 hour ago, Wooly15 said:

New drums are arriving today, and I have a question about the shoes. They'e been on the car less than a year with not many miles. Do they need to be replaced along with the drums?. I know when doing new shoes, you should turn the drums so the surfaces are fresh, but I didn't know if the relatively new shoes would be ok. Wouldn't they just wear to the new drums?

The shoes do not need to be replaced but you will more then likely have to back them off to get the new drums on. I would suggest that you take some 80 grit sandpaper and sand the linings. ( Check your old drums over to see if there are any spots showing where a weight had broke off. I had that happen on my 46 Chevy and it made quite a vibration.