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Throwout Bearing Swap for Easier Clutch Action

November 21, 2011 | Troubleshooting & Repair
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!

Procedure
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.

Stephenson_2

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.
Stephenson_3
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.
Happy motoring!

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.”

6 Comments

Profile missing thumb
Wm. C. Ledgewood
May 18, 2012 at 6:47 AM
You can vaguely make out a part number on the bearing in the picture. Looks like it is manufactured by FS&T. Could you list the different bearing manufacturers and part numbers? A side picture of the bolts after they are modified and installed. Thanks, Bill L.
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Peter Poulikakos
July 28, 2012 at 11:43 AM
Hi,<br />Does it matter which type of pressure plate is being used ?
Profile missing thumb
Wm. C. Ledgewood
May 18, 2012 at 6:47 AM
You can vaguely make out a part number on the bearing in the picture. Looks like it is manufactured by FS&T. Could you list the different bearing manufacturers and part numbers? A side picture of the bolts after they are modified and installed. Thanks, Bill L.
Profile missing thumb
Peter Poulikakos
July 28, 2012 at 11:43 AM
Hi,<br />Does it matter which type of pressure plate is being used ?
Needsrestoration
Al Zim
June 30, 2014 at 6:35 PM
It seems to me that the resistance to the release of the clutch disc is directly related to two factors. The first being the rust and and dirt on the pressure plate and the second being the wear on the pressure plate. As the pressure plate and disc wear the clutch becomes harder to depress. If you are using a pressure plate that has excessive pressure this will be harder to depress and not needed. When I first started racing we used the VW bus pressure plate and a solid disc. 100 horsepower is probably all we had available and the cars were heavy. Unless you are slipping in 4th gear there should be no need for more spring pressure in the pressure plate. I good technician can tell you how many foot pounds of torque will be necessary to make everything work properly. Regarding contact between the pressure plate and the throw out bearing. As the clutch disc wears out the amount of free play reduces between the pressure plate and the throw out bearing. No free play as suggester by the authors will soon result in a slipping clutch and a flywheel that will need resurfacing. Set your free play so that you can feel the diaphragm of the clutch go just over center than adjust the stop on the pedal board. I prefer a lot of free play and and the clutch releasing off the floor. IN SUMMARY: If the clutch is hard to depress replace all the parts and it will become smooth as silk. Remember when the flywheel is resurfaced check to make sure it has the correct specifications. DO NOT USE FLYWHEELS THAT ARE MADE IN A PACIFIC RIM COUNTRY THAT USES THE VW 200MM PRESSURE PLATE, al zim (Zim's Autotechnik) copy-write 2014 all rights reserved
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Juha Vane
October 20, 2018 at 12:40 PM
The bearing I used: P/N 901.116.081.11