By Craig Stevenson, Volume 30 -1 May / June 2006
In an effort to make your 356 more comfortable for the future, let me share an upgrade that will not interfere with the originality of your car and will give especially great advantage to those haunted with leg and hip problems. In my years of working on 356 cars, I have seen several owners having to sell their cars simply because they just could not use the standard shift clutch anymore. Automatics? Please!
The simple answer is to replace the 356 throwout bearing with an early 911 type. You cannot, however, just swap the bearings. First, the transmission must have the guide tube-design throwout bearing type 741 used from 1960-65. Sorry about those who have early A and pre-A cars, but for those who are utilizing the later 741 boxes in A cars... lucky you!
This may seem like a lot of hassle, but let me explain the advantages. The 901 throwout bearing has a much longer center collar that rides on the bearing guide. The bearing is better centered and steady as it travels toward the pressure plate diaphragm. This will allow the bearing to meet the pressure plate correctly. This also adds to the life of your pressure plate and guide tube now that the bearing will not bind or wobble as it travels on the guide tube. The bind and wobble can also create resistance to the clutch cable and affect the clutch pedal pressure.
In addition, the 911 throwout bearings are ten times more durable than the early 356 type. Most likely you will never have to replace it again. And the clutch pedal is soooo soft, practically anyone can drive a 356 car!
After removing the engine and 356 throwout bearing from the clutch fork, you will see the guide tube mounted to the transmission at the spline shaft. Remove the three 6mm nuts and guide tube. If the guide tube shows excessive wear, I recommend replacing it now that it is out. Double nut the three studs and remove them from the transmission housing. Using an oversize drill bit, countersink the three bolt holes of the guide tube to incorporate the new tapered screws you will be using to replace the guide tube to the transmission. I have found using old 6mm small head tapered screws from the outside of A-early B seat rails works best (see photo). This allows the new 911 thicker throwout bearing to rest farther back from the clutch assembly.
On the back side of the 911 throwout bearing, you must remove the lower left and right ridges just below the posts. In hand with step #1, this gives clearance for the guide tube base allowing the bearing to rest farther back from the clutch assembly. See red arrows in photo.
Be sure to grease the guide tube and throwout bearing posts. The fork must be centered squarely to allow the throwout bearing to slide easily onto the guide tube.
You will be really surprised how well this works. Also, while doing the throwout bearing and guide tube upgrade this will give you the opportunity to change that old leaking rear transmission spline shaft seal.
Paul Bernardo adds: “I have been doing this conversion for over 15 years for many friends and my own C series cars. I find that in addition to a much more fluid feel and softer pedal, in most cases I have gotten nearly double clutch component life. This is due to two main problem solvers. Most important is that a 901-style bearing is capable of running in contact for a long period of time as it is a properly sealed unit with high quality bearings and race inside. Also, the fit on the guide collar is a 50% closer tolerance so there is little chance of rocking and binding. The most difficult problem encountered in this procedure is getting the clearance to install the longer bearing as far forward as possible so as to not lose the gap when installing it. This is done in several ways - all which involve removing the original studs that secure the guide tube and replacing them with specific bolts. A 356 will benefit from this update and broken clutch cables will be long forgotten.”