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Driveshaft disc near disaster

Started by Touring29, June 18, 2022, 03:31:50 PM

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Touring29

The last post about the clutch install actually happened a couple o weeks ago. Fast forward to Thursday. My wife is planning on driving the 29 in our local Jim Bowie parade a week from Saturday (today). I thought I had everything good to go but we wanted to drive it on a hot day to make sure it won't overheat. She drove it around town for about 30 minutes and I got the call. I'm in trouble the car made a lot of noise and now it won't even roll and its in the middle of the street.

When I got there and crawled under it I saw why. The front of the driveshaft had torn loose on two of the three lugs and was wedged against the e-brake as you can see in the picture. The discs were new and had less than 20 miles on them. I'm not going to say where they came from but most of you know. If you have these discs I hope you have better luck than I did.

I went home and got some tools then spent about 30 minutes under the car getting the driveshaft out. We borrowed a rock from someone's yard decorations to chalk the wheel so it wouldn't roll away when I got it unhung. Then we carefully towed the old girl home and got the neighbors to help us push it in the garage. Not fun on a 100 degree day!

I have the old discs back in for the parade. They are in terrible shape and I used fender washers where they were the worst. Even though they are very old they were still together when I replaced them and I feel they are made out of far better material than the new ones I bought.

I informed the seller and he claimed his discs were stronger than the old ones but he has had a "few" problems with them. There is no way they are as good as the old material as they are mostly hard rubber with some strings in them. I am going to put the pieces in a envelope and send them back.

chetbrz

I believe in another post you mentioned that these disks were a different thickness then the originals which caused you to use 3 at the transmission.  There should be 5 disks, 2 at the transmission and 3 at the drive axle.  Did you have 3 and 3 which might have been to tight to allow for the necessary flexing of the disks.

This issue is very dangerous.  If she was driving at 35mph there could have been greater damage if the drive shaft broke loose. 

I wouldn't use any replacements he sends.  Find a new supplier with the correct disks.  I'll also check around. 
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

Touring29

These discs are 1/4" and he sent 6. I called and ask where should I put the last one and he said the front. 6 discs at 1/4" are still a little short of the original 5 at 5/16" but only 1/16" so I added a washer between the lugs on the driveshaft and the disc to make it up. I used all the waffle washers I had but had to use some regular washers which are also thinner. I added a washer on the other end to make up for that. When installed with the weight on the wheels the shaft was just touching and had no pressure or gap.

I am going to find another solution and it won't involve any discs made like his!
These look like they might be better. I also may just have a regular driveshaft built with a slip joint.
https://www.colletizer.com/store/p72/Universal_Joint_Flex_Disc_and_New_Washers_L373T.html#/

chetbrz

#3
Rapid CNC appears to have the correct disks.  You should only need 5 disks, 2 at the transmission and 3 at the rear axle.

BTW if you go the new driveshaft route, please keep this site informed on the solution and cost.

Tks, Chet,,,
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

Russ T. Fender

Letting go up front is bad but if the rear lets go and it cuts the brake line you are in real trouble. I bought new discs a long time ago so I can't even remember where they are from which is a bit unnerving given your experience.  At least they are the correct thickness.  While I don't like to say anything bad about vendors who are supplying our hobby with much needed parts, this is a very serious failure.  I for one would like to know who the supplier was and would appreciate a private email if you are reluctant to post it on the forum.  Thanks.

Touring29

Hey Rusty body part (I know how you feel mine are all rusty) does your driveshaft have slip joint to accommodate the suspension travel or does the discs have to absorb it? Mine is a solid shaft but I think any disc would last a lot longer if it wasn't.

Russ T. Fender

I am running the original solid shaft but I welded a piece across the frame to protect the brake line.  The Plymouth club recommended it and sanctioned it for judging for those who are into that.  I plan to convert to a modern U-joint set up eventually because of the vibration.  My car was in everyday service by the original owner and had the original fabric discs in it when I got it so the original discs were obviously more than adequate. The odometer read 78,000 miles when I got and the owner said he couldn't even remember how long ago it had stopped working. There is plenty of play in those discs in the rear, the drive shaft can twist up and down and sidewise way more that it would have to in normal service.  The problem is that they cannot be balanced to eliminate vibration or in your case they are not made correctly.  The type of discs that I think you wound up with are used on stationary machinery to drive shafts where there is little or no flexing and they are used primarily to dampen vibration.  I have lots of old worn discs and they are more woven fabric than anything else and that is what gives them the strength needed to stand up to the torque stress

chetbrz

Quote from: Touring29 on June 18, 2022, 06:38:50 PMI am going to find another solution and it won't involve any discs made like his!
These look like they might be better. I also may just have a regular driveshaft built with a slip joint.
https://www.colletizer.com/store/p72/Universal_Joint_Flex_Disc_and_New_Washers_L373T.html#/

Have you decided on a solution yet?  Just curious.
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

Touring29

I talked to the vendor who I linked to above and he has both 3/8" and 5/16" I am pretty sure our cars used 5 5/16" discs and I may go that route even though I would have to buy one more disc. He claims his are made out of fabric like the originals and hold up well. I'll probably order them Monday unless something happens to change my mind. 

The parade is tomorrow morning and I have been working on getting three cars ready that will be in it. The 29 Plymouth a 56 T-bird and a 60 TR-3. All 3 will be driven by women Its predicted to be over 100 degrees so I am a little nervous as I want them all to have fun and not have any problems.

Russ T. Fender

For what it's worth I use 5 5/16 discs on my car and they fit perfectly.  Two in front and three in the back.

Touring29

Discs ordered from Rapid CNC. I went with 5 5/16 like the factory setup. I hope these are better than the last ones from the only other vendor I have found.

Touring29

The discs from Rapid CNC came in a few days ago and I got them installed yesterday. They look a lot like the ones I got from the other vendor but the similarity ends there. They have a lot more fabric in them and are a lot stiffer. I think I could have folded the others in half if I tried and these there is no way. The others seemed to crush a lot when I tightened the bolts making it hard to get them tight before the nut bottomed out on the shank of the bolt. These tightened up tight without deforming much.

I drove it this morning and it felt good but the other ones did too until they failed.  I didn't cotter key the bolts yet, I used some hairpin type pins which are easy to remove. I am going to run it a little while and check the bolts. When the are broke in I will retighten them and use cotter keys.

chetbrz

Just curious, how did you run the car in the parade if you just got the new disks now. 

BTW I don't think you should over tighten your disk bolts.  I don't believe they should deform the disks. 
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

Touring29

I put the old discs back in that were in it before I decided they were on their last mile and ordered the set that blew apart. I had a wide assortment of fender washers, waffle washers and regular flat washers along with a prayer holding them together. I have had that driveshaft out about a half a dozen times now and am ready to move on to something else. On a happier note I worked on my 56 BelAir some today even though it got to 106 degrees.

chetbrz

Quote from: Touring29 on July 08, 2022, 08:22:59 PMOn a happier note I worked on my 56 BelAir some today even though it got to 106 degrees.

Cool Car, Hot Day.., living the Dream  :)

http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member