30-U universal joints

[Russ T. Fender]

Has anyone changed over from the disc setup and if so what did you do?  I have never been able to eliminate the vibration from the drive shaft at speeds over 30 and would like to go to a better setup.  I am also a bit concerned about the possibility of the rear discs letting go and taking out the brake line so it is also a safety issue for me.

[chetbrz]

Check out this post:

http://www.1948plymouth.info/28Q29U/index.php?topic=562.msg2907#msg2907

Vibration from the drive train isn't a good thing.  I have given thought to this also.  I like the setup Tinkeys came up with.  There is a gentleman near me, Joe Hernandez (x-POC National President) who did something similar to his car many years ago.  I have been meaning to stop by and check out his setup but the stars just haven't aligned and right now isn't the time.  I think besides the Universal Joints at both ends the drive shaft needs a spline slip gear.  Just my 2 cents.

I am looking for a article detailing how to put a U shaped metal bracket around the drive shaft on the rear frame support.  This keeps the disconnected drive shaft from flailing out and cutting the rear break line.  Simple and effective safeguard.

Very Interesting Topic,  Chet...

[Articifer Tom]

A search on AACA forum will show plenty . There are shops that build them for about 250 -450 dollars . With two modern universals and a slip joint . Some use your ends and get it balanced . You can cover the joints with leather boots to hide .
  All race / stock car owners will know who and where these places are .

[Russ T. Fender]

Chet,  years ago the Plymouth club endorsed the use of a bracket to catch the driveshaft if it let go and changed the judging guidelines so that you would not lose points for the modification.  Unfortunately,  I don't remember exactly how it was designed.  I wonder if anyone has that modification on their car and can post some pictures.
As far as using modern U joints is concerned, I would think that it would be fairly straight forward if it was not for the brake drum. Since the brake drum mounts on the yoke,  modifying it for a modern U joint would seem to be a little tricky.  I seem  to remember someone saying that the yokes on the '31 CM Chrysler were the same spline and that the set up was a bolt on change that only required shortening the drive shaft.  However, I searched for years and could never track that set up down.

[chetbrz]

Russ,

I think the U shaped metal bracket is pretty straight forward and probably in one of the Bulletins.  As far as the driveshaft is concerned I would assume that something would mount to the same three fingers that the disks mount to.  A would suggest a round steel disk with a universal joint and the same for the differential.   The drive shaft would be sectioned with a spline slip shaft.   No Plymouth parts modified you would just bolt on the new drive shaft to the existing transmission and differential.

As Tom suggested, there is a local drive line shop near me that I know could do the job I just can't lay out any more money at this point.., the restoration is getting quite expensive.  Maybe down the road a piece.  It might be one of those things that costs as much to make one as it does to make a couple of them. 

Chet...

[frankp]

Chet, you're right, the bracket was in a Bulletin.  I don't remember which.  I thought it was installed closer to the transmission than differential.  I think John is using one.

[Russ T. Fender]

I would think that the bracket needs to be in the rear to protect the flex hose. I have decided to give the discs one more try.  My old ones were pretty worn and I am hoping new discs will work better.  If not I will figure something out to convert to a modern system.  That said, does anyone have a source for the "waffle" washers used between the discs?  Mine are pretty beat up.

[frankp]

I don't have a source for those washers.  The rubberized disks were used on several makes; don't know which though, so they should be a round.  I never found any when I looked, but that was a search by mail.  As long as the holes are 60 degrees apart, you should be in good shape.