Drive shaft customers here in the Miami/Ft. Lauderdale area definitely have a lot of interesting cars. Sometimes, you get a call from a customer asking you to do something you've never done before. In this case, the customer had a 1992 Italian Lancia Delta. He'd called several driveline service shops and no one would agree to take on the job. When he called us, admittedly, it was a maybe. The drive shaft the customer brought to us ended up using a Rezeppa style constant velocity unit on one end and a normal universal joint flange on the other.
After determining the size of the Rezeppa CV and the flange pilot, I knew we'd have to machine a pair of custom fixtures for our drive shaft balancer. This would involve quite a bit more time than the average balance job. The customer, however, was eager to get the vibration out of his drive shaft and quickly agreed. In order to save the customer time and money, we opted to machine the balancing adapters out of aluminum. Since we would only be using these for one balance, aluminum is fine. Of course we can always make new adapters from cold rolled steel if we start seeing more of this shafts that need servicing.
In the above photo, we're machining the adapter for the Rezeppa CV. It needed to match the outside diameter of the constant velocity unit as well as provide relief inside for the raised portion at the front of the assembly.
Once we got the "deep dish" adapter machined for the drive shaft balancer, it was time to make a simple flat adapter for the differential. The pictures of the adapter didn't turn out too well but below is an example of another one we'd machined before.
The above photo shows an example of the type of adapter we custom machined for the Lancia Delta drive shaft. This particular drive shaft balancing fixture is made of steel. The one we made for the Lancia was made from aluminum since we were only using it one time.
With both adapters made, it was time to attach the Lancia Delta driveline to the balancer. When balancing a drive shaft, it is important that the shaft run concentrically during the entire process. This means that the adapters had to be machined to tight tolerance to fit both the bearing plates as well as the drive shaft when affixed to the balancer. Since this drive shaft was a two-piece with a center support/carrier bearing, we also needed to make sure said bearing was elevated with shims to keep everything nice and level.
In this picture, we've got the drive shaft mounted in the computerized drive shaft balancer and ready to be balanced. We've attached the Rezeppa CV end nearest the drive motor and the flange/differential end on the opposite pedestal. It's a little difficult to see in the photo, but we've shimmed the carrier bearing so that the driveline will run level during the balancing process.
The Lancia drive shaft, like all two piece drive shafts, is balanced using sensors at three different mounting points. These points include the transmission connection point, the center support/carrier bearing, and the end of the drive shaft where the flange connects to the rear differential. With everything mounted securely and level, we calibrated the balancer to the drive shaft and balanced it. In this case, achieving complete balance required only 20 grams of weight on the differential end of the drive shaft. The customer called once the shaft was balanced to tell us that all was well and his drive shaft was now running smoothly. At Proshaft, we enjoy challenges like this and welcome any inquiries you might have if you're having trouble finding a drive shaft service to handle something out of the ordinary. Thank you for reading!