Triumph Repair: Spitfire knocking, flange bolts, prop shaft

Question
Hello!  I have owned a 1973 Spitfire 1500 for ~11 years now and love it.  Recently, my left rear axle flange shattered (fortunately at low speed).  I ordered a new flange and UJ, and took out the whole half-axle assembly to a local shop to have the new flange attached. Shortly thereafter, I decided it was time for a new leaf spring and new shocks (Spax adjustables).  The rear left of the car has always sagged a little lower than the rear right, so I was hoping a new spring and shocks would rectify that (it did not -bummer). In the process of replacing the spring, I also decided it might be prudent to renew the right side UJ and the rear prop shaft (strap-type) UJ, just so all three in the rear would be new.  I was still getting a "pop" when taking up the drive after the left side repair, which is what prompted me to replace the other two UJs.  Long story short is that after getting the entire rear put back together with the new spring, shocks and UJs, I am now getting a knocking sound during acceleration and deceleration, which seems to emanate from the right side of the car.  Is it possible that the updated, stiffer suspension has caused some binding on one of the new UJs?  Could it be a bearing gone bad?  Could my differential be acting up?  If it is the new UJ on the right (still trying to figure out how to narrow down the cause), what can I do to get rid of the knocking?  Would it be helpful to undo the flange bolts and rotate the axle flange to a new position to see if that alleviates any binding?  Any help would be great.  Thank you!  

Answer
Steve,

The first thing to do is to make sure all the bolts in the driveline are properly tight.  The drive axle bolts, prop shaft bolts, and importantly, the lugnuts!  See if that helps with the problem.

If the sound is apparent at low speeds you might try having a friend drive the car in a circle around you in a parking lot and see which side is "louder".

It is possible that the new u-joint is binding.  It's not uncommon for the u-joint yokes to get distorted, whether from use or from someone at the shop being a bit ham handed while trying to pull them apart.  If the yoke was tweaked a bit and the shop forced the new cup into the yoke then the u-joint could be binding.

You can also try putting the car up on a lift or on jack stands with the trans in neutral and rotate the wheels (or have that friend rotate the wheels) slowly and see if you can hear or feel vibration from either of the u-joints.  If you hold one wheel stationary and rotate the other wheel it will also put the driveshaft in motion.


Cheers,

Jim