New u-joint for old Plymouths

[Gary 30U]

Ditch the disks - Update your early Plymouth
This was brought up on another thread, but thought I would sart a new topic.

Like most of us with the early Plymouths and the disk type flex joints in the drive line I had contemplated replacing the disks in my 30U Business Coupe and finally found some. They were 5 that were left over from a job that a company in Portland, OR had done some years ago. After I got them I was concerned that they were not machine made and it appeared that they might not balance really well. At that point I decided to look at my options of installing new style U-joints.

I found, with a little research, that it should be a fairly easy conversion. There are only two parts that are specialty parts associated with the original Plymouth. The rest of the parts necessary are stock parts from any driveline store.

First, I removed all of the original driveline, including the parking brake system and the rear spider yoke off the transmission and the one from the front of the rear differential. I found that the yoke from the transmission had a grove worn in it so I took it in to have it built up and resurfaced.

I took the yoke from the front of the differential and used this piece as the front of the new driveline. This is the first of the two parts that are special to the Plymouth. This yoke can be bolted directly to the yoke on the back of the transmission and the two will hold the original parking brake drum in its original position. I bolted these pieces directly together using new grade 5 bolts with lock washers and locking nuts. Probably overdone here.

From here back everything is new. They welded a new universal yoke and slip-joint assembly to the original spider yoke taken from the rear end. Then they made a new tube with rear universal and a new yoke to fit the differential. This part is the second part that is special. This yoke (for my 30U) is Spicer part #2-4-2821-1X which is a 1 1/8" X 10 spline, 13-10 series. The new yoke at the differential solved the problems of wear in the original piece. Couldn't find a new seal for the differential, but was pleasantly surprised to find that just a new yoke seemed to solve the seal leak problem.

Oh, by the way, the overall length of the shaft assemble, from the front of the spider yoke to the rear of the back yoke is 55".

This job should be able to be done by any competent driveline shop in your local area. Mine was done by Will at Driveline Service of Portland, Inc. You can contact them at 800-227-8608 or www.driveshafts.com.

Wll try to post a coule pictures.

[Gary 30U]

Trying to post some pics.

[Gary 30U]

maybe another one.

[Gary 30U]

And another.

[Doug]

Mid 30U came out with a drive shaft like that. I Like it and it looks like you did a first class job on yours. But I like the disc just because they are diffrent

[Gary 30U]

I actually have a spare spider yoke for the rear end but it needs resurfaced. I am thinking of putting mine back to original at some point. But, I've got so much invested in this conversion I at least need to give it a try.