TR4/4A Drive Shaft - Prop Shaft Alignment and Balancing

[RJS]

Hi

As some of you may have seen, back on Sept 8, 2023 I posted about "Chassis Buffeting" at speeds around 55-60mph. > TR4/4A - Chassis Buffeting(?) < No shake in steering wheel but, entire car vibrating/shaking making it not pleasant to drive at those speeds. Well, based on some comments in that thread, I really began to suspect my drive shaft was not balanced or assembled out-of-phase.

I finally got under the car this morning and guess what? I could faintly see the alignment arrows on the drive shaft front and rear sections (extremely faint - but legible) - and the arrows are ~120 degrees out of alignment - which puts the forks of the u-joint flanges equally out of phase!! I am now 99.9% certain this is the source of my shaking.

So, next up on the list is to remove the drive shaft, disassemble, clean, reassemble in the proper alignment, grease and reinstall.

Does anyone know if removal can be accomplished from below? I am hoping I can get away with removing the exhaust, disconnect each flange (4 bolts each) and slide it out from the rear, over the "T Shirt".

Bob

 

[RJS]

Update: pulled drive shaft this afternoon. Decided to drop rear cross box muffler and intermediate exhaust pipe. This significantly improved access to the flange nuts/bolts. From there, easy-peasy. Unbolted and she dropped right out. Slid out forwards. Took less than 2 hours from assessing the job, deciding to pull exhaust, pulling exhaust (likely 50% of the time as the pipes have been joined for nearly 25 years!) then unbolting the 9/16" fasteners. If I did it again, I am sure I could do it in one hour.

Splines slide easily. I was able to unscrew the dust cap, separate the drive shafts, align the "arrows", and join the two halves again. The u-joint flange yokes are now 100% in-phase. I also noticed each shaft was stamped with "208075" which also coincidentally lined up after I aligned the arrows on each drive shaft.

I could have easily popped the drive shaft back in. But, since I have it out, this weekend I'll clean it up, paint it and make it look new. I also ordered a new dust cap, cork gasket and steel washer. Hardy Spicer part no. D2C - $15 on Amazon. I'll probably also renew the 9/16" bolts and nyloc nuts.

Bob

 

[auprichard]

For the sake of $40 or so, why would you not replace the U-joints which you have it out?

 

[Popeye]

For the sake of $40 or so, why would you not replace the U-joints which you have it out?

Agree. And I believe you want the u-joints with grease nipples.

You could go crazy and get the full TRF kit including the special fasteners (Stover nuts) for the shaft installation. But TRF charges nearly as much for the fasteners as the u-joints.

 

[sp53]

The last time I did it, I pulled the tunnel and unbolted the front there. I like the way you did it and you could do the exhaust also.

I stopped fixing the U joints and balancing and take the removed unit to a specialized driveline shop for professional balancing and U joint replacement. My car is smooth on the freeway. You probably have one close by. The shop I know about is in a small industrial town close by that services a lot of big trucks and whatever. Plus they cleaned and painted it very reasonably and found the U joints with no problem. The U joints could be a common size I do not know and they are not a cheepo. Their turn around was like 2 days.

steve

 

[RJS]

Gents

Good ideas. The old "while your in there..." Hopefully I can locate a shop which is good, nearby and quick. Usually if you're lucky, you get 2 of the 3.

Bob

 

[mctriumph]

And my dime is, Take it to a drivetrain shop and have it balanced after you clean it up .
The factory only got it so close.
Mad dog

 

[RJS]

So, to close this loop a couple weeks later, drive shaft is back in the car. Sooo much smoother and more comfortable at speeds over 50mph. The main item was putting the drive shaft back "in phase" and installing two new u-joints.

The car is a real pleasure to drive at speed now. Added benefits are 1) shaking/rattling of gear shift lever under hard acceleration is gone and 2) notchiness going into 3rd gear is gone.

"Rebuild" included two new u-joints, cleaned, painted and reassembled drive shafts "in phase". Lubed driveshaft splines with moly graphite lube, Renewed metal split washer and cork gasket using Spicer Dust Cap kit (part #D2C). Note, while washer and gasket were correct size, the dust cap itself was too large so I simply reused the original. Installed with new hex bolts and nyloc nuts (note, bolts from Moss were too long (1-3/16") and I had to cut them down to 1" length not to hit differential). Only thing more I could have done would have been to take it to a shop to have it professionally balanced.

Last, I also watched a seven part YouTube series by Prof John Kelly of Weber State University - this is anything/everything you'd ever want to know about u-joints. Really excellent and professoinally produced. Part 6 is how to install u-joints the correct way and part 7 goes into setting axial play using various thickness snap rings: https://www.youtube.com/playlist?list=PLIn3FrDiB1lzPwKJf1MsEAEJ37vyjdAuJ

All in all, very pleased and now just upset at myself for letting this issue linger so long. I attribute the drive shaft being out of phase to a supposed British Car Mechanic (aka hack) who replaced one of my u-joints back in 2006! Another reason I try and do all my own work now.

Bob

 

[mctriumph]

The 59 I had to scrap last week had been parked for the final time due to driveshaft issues.
Mad dog