I recently posted a thread describing an obnoxious noise in my model T. Forum participants all pointed to the U joint as the culprit. Now my question, is there a technique or method for confirming the U joint is in fact to blame without actually removing the existing joint to inspect? Thanks in advance for your continued assistance. Dewey
Arthur has the rear axel been overhauled? If not it could be the rear axel Babbitt washers failing. The sound could travel up the driveshaft tube making you think it's the u-joint.
I would think one could throw the handbrake forward to engage the clutch and roll the car back & forth in gear to see how much it will move without turning the engine over ?
Maybe, maybe not.
One could jack up one rear wheel and try to determine how much slack is in the drive train but you would have to account for R. & P. backlash.
Pull out the plug for the U joint pin, and take off the inspection plate for the transmission. Then with one wheel jacked up and the parking brake forward in high gear, chock the other wheel both front and back. Have someone rotate the jacked wheel as far in one direction as it will go and then back in the other direction as far as it will go. While the jacked wheel is being rotated, look down the small hole to see if the drive shaft is moving. If it moves back and forth look at the driven plate in the transmission to see if it moves with the driveshaft. If it doesn't move, you have a loose U joint. Note, the rivets could be loose on the drive plate. That would also cause a clunk. Either problem should be addressed.
If neither the U joint or drive plate show looseness, jack up the other rear wheel and try to move the axle in and out of the tube. any noticeable play here indicates you need to replace the thrust washers. This is a good test to make even if you have a loose U joint. One other part which can come loose is the nut on the end of the driveshaft which holds the pinion gear. This should also be fixed if found.
For what it's worth here are some notes from my journal regarding my experience with U-joint noise.
On The Presidentís Tour in June I noticed oil was dripping rapidly from the U-joint / ball cap. We completed the tour, about 50 miles, and since then I have taken the T on several outings. The oil is still dripping but maybe not as fast. Even after all the driving oil still runs out of the top petcock, so I must have overfilled the engine at the last oil change. This may have encouraged the drip.
Yesterday I took the Model T to Bowness Auto to pick up a rad hose for our T-bird and noticed a dull thud or thumping sound when the engine was under load. I emailed Harry about the problem and we independently came to the conclusion that the grease had been washed out of U-joint / ball cap by the oil drip.
I pumped grease into the ball cap until my arm got tired and took the T for a short drive. Problem solved, or at least the symptom is masked.
Here is what I learned:
It's not likely the u joint but in the rear axle or driveshaft.
Robb, I use the modern pinion and the modern thrust bearings, I have never had a problem with the u joint not being pinned. Between mine and a friends we have over 150 k on this set up with no problems. KGB
Keith, it could be that my U-joint wasn't that good to start with. It has thumped off and on like this for 15 years. Over the next week or two I may discover the problem. On our way home from a mountain camping trip last week I broke something in the rear end and the Ruckstell only shifts into neutral. Henry still works fine. Tomorrow I will pull the rear end and check everything out.