911 Clutch Replacement
Page 1

Difficulty Level 7

Difficulty scale:
Adding air to your tires is level one
Rebuilding a 911 Motor is level ten

Figure 1: Complete 915 Clutch Package

Figure 2: Special Tools Needed

Figure 3: Old Clutch (901)

Figure 4: Removing First Pressure Plate Bolt

Figure 5: Flywheel Locked, Removing Pressure Plate

Figure 6: Prying Off Pressure Plate

Figure 7: Removing Flywheel Bolts

Figure 8: Clutch & Flywheel Removed

Figure 9: Removing Old Flywheel Seal (915)

Figure 10: Removing Flywheel Seal (901)

Figure 11: Flywheel Seal Removed (915)

Figure 12: Cleaning Inside of Case (901)

Figure 13: Tapping in New Flywheel Seal (915)

Figure 14: Pressing in New Flywheel Seal (915)

Figure 15: Flywheel Seal Installed (915)

Figure 16: New Flywheel Seal Installed (901)

Figure 17: 915 Pilot Bearing

Figure 18: Fastening Pilot Bearing (915)

Figure 19: Pilot Bearing Attached (915)

Figure 20: Installing Flywheel Pilot Bearing (901)

Figure 21: Pilot Bearing Installed (901)

Figure 22: Resurfaced 901 Flywheel

Figure 23: Resurfaced 915 Flywheel

     Replacing the clutch on a 911 is a job that can be performed by the home mechanic equipped with a little knowledge and a few special tools.  The actual job is not very difficult, as long as you follow the correct and proper steps.  Performing the clutch replacement yourself can save you hundreds, if not thousands of dollars, and also teach you a little something about your car.

     The very first task in performing the job is to obtain all the parts and tools that you will need.  Pelican Parts offers a complete clutch replacement kit with everything that you will definitely need for the job.  In addition, we offer a supplemental package of items that you may wish to order as insurance.  These are items that most likely will not need to be replaced, but due to the nature of the car, may need replacement.  We don't recommend cutting corners on the clutch job to save a few bucks.  If you're investing the time and energy to do the job, you might as well do the job right.  Figure 1 shows a picture of all the parts that you will need to do the job right for a 915 transmission (1972-86):

     Pelican Parts sells a complete package with all of the parts that you need to do this job.  Please click here to find out the current price on this package.  Your continued support of Pelican Parts insures that these technical articles, and our friendly, convenient customer support of the 911 will continue into the future.  Please email us with any questions, or to place an order for our complete clutch replacement package.

     Additionally, there are a few special tools that you might need to perform this job:

Pelican can supply all of these tools (shown in Figure 2) for you.  Please email us with any questions or requests.

     One of the first things to realize is that there are 3 different types of transmissions that were used on the 911s from 1965.  This clutch article covers the 901 and the 915 transmissions, but the G50 transmission (introduced in 1987) is quite similar to the 915.  As a result, replacing the clutch on a late model Carrera or a C2/C4 is similar in principle to the procedure outlined here.  The early 901 transmission was used in 911s from 1965 thru 1971.  This transmission used a push-type flywheel (up until 1971, when Porsche switched to a pull-type).  With the pull-type, this means that the throw-out bearing pushes against the pressure plate in order to release the clutch disc from the flywheel.  On the later cars (1972-86), Porsche deployed the 915 transmission, which uses a pull-type pressure plate.  With this setup, the throw-out bearing is physically attached to the pressure plate, and pulls the pressure plate away from the engine, releasing pressure on the clutch disc and the flywheel.

     No matter which transmission you have, the procedures for replacing the clutch are similar, and both the 901 and 915 are covered in detail in this article.  As mentioned previously, the G50 is similar to the 915 in setup, so there should be a lot of overlap from the instructions shown here.

     Ok, after you have gathered all your tools that you need for the clutch job, you need to remove the engine from the car.  Complete step-by-step instructions are shown in our Pelican Technical Article, 911 Engine Removal Made Easy.  It is important to note that you don't need to drop the transmission with the engine in order to do this clutch job.  In fact, I don't recommend it as it is much more work.

     Once you have the engine out the car, the replacement of the clutch is quite easy.  Figure 3 shows what your clutch (901 transmission) should look like when it comes out of the car.  The first thing that you need to do is remove the pressure plate from the flywheel.  You can do this without spinning the flywheel by following the method shown in Figure 4 (901).  Simply place a breaker bar in-between the socket and a single stud on the engine case, and turn.  The breaker bar should prevent the pressure plate from turning.  Then, attach the flywheel lock as shown in Figure 5 (901) The flywheel lock is basically a piece of metal with two holes in it.  I usually use left over 914 motor mount bar holders, but I couldn't find one for this article.  Instead, I used a small homemade flywheel lock that consists of a piece of metal with two holes in it.  By attaching one end to the flywheel, and the other end to the case, you prevent the flywheel from turning.  Once you have the flywheel lock in place, loosen the remaining pressure plate screws.  If you are planning to reuse the pressure plate over again, be sure to loosen the screws uniformly.  It is not recommended that you reuse the pressure plate unless you have just recently installed it and are removing the clutch to repair something else.   After all the screws have been removed, you can then pry the pressure plate out from the flywheel using a screwdriver, as shown in Figure 6 (901).  The disc should come out easily after the pressure plate is removed.  You may want to have a vacuum cleaner to vacuum up all of the clutch dust that may have accumulated over the years and subsequent wearing out of the clutch disc.  The older discs were made with asbestos lining, so be careful not to inhale too much of the stuff.

     After the area is all cleaned up, the flywheel should be visible.  Now, reattach the flywheel lock carefully, as you will be applying a great amount of force to remove the flywheel bolts.  On the 915 transmissions, remove the three bolts that hold on the pilot bearing.  Use a long breaker bar and eat your Wheaties before you try to remove the flywheel bolts.  The inner flywheel bolts require a special flywheel bolt tool to remove.  They are torqued down very tightly, and WILL NOT come off without this tool.  In fact, they very often will not come off with the tool, and if you are not lucky, then they might strip out, and you will have to grind off the bolts.  Make sure that the flywheel is locked securely, and then use a breaker bar and the special tool to remove the flywheel bolts, as shown in Figure 7 (901 transmission).  Be sure to use only good quality tools; you don't want the tools breaking on you and stripping the flywheel bolts.  From my own personal experience, drilling and grinding out flywheel bolts is a horrible way to spend a Saturday afternoon.  

       When the bolts are removed, the flywheel should just pop off of the crankshaft end.  Once the flywheel is off, your motor should resemble Figure 8 (1974 2.7 911S motor).  This shows the end of the crankshaft exposed, along with the crankshaft seal.  If there are any oil leaks around the seal, they will be apparent.  The entire area will be oil soaked or dirty.  If you press on the seal with your finger, and oil rushes out, then you need to replace the seal.   Seals may be damaged by old age, or they may even be melted by a slipping clutch heating up the flywheel.  I personally recommend replacing the seal each and every time you do a clutch job.  You would hate to put the entire engine back in the car, only to find that you nicked the seal, and now a $10 seal is causing a huge oil leak that will require the engine to be removed once again.  It's just not worth it.  Replace the seal while you have access to it.

     To remove the flywheel seal, get a screw driver and a small plate (in this case, my flywheel lock), and gently pry out the seal.  It is important not to touch anything metal with the screwdriver; you don't want to scratch or damage any tight seal areas.  Prying out the seal as shown in Figure 9 (915) and Figure 10 (901) basically avoids any damage to the case or the crank.  Figure 11 (915) shows the flywheel seal completely removed from the engine.  At this time, you should clean the engine case if you need to.  Some of the solvents used to degrease and remove oil can damage the new seals that you are installing, so it's best to use them when you don't have your new flywheel installed.  Clean, rinse and dry the case as shown in Figure 12 (901).  

     Now it's time to install a new flywheel seal.  To install the new seal, simply place the seal up against the case and tap it in.  I would use a rubber hammer instead of a metal one, as this is less likely to cause accidental damage.  Tap evenly on all sides of the seal, and with a little coaxing, it should go right in.  Sometimes a rubber mallet will not do the job, and you need to carefully use some other tools, like a regular hammer (Figure 13, 915) or a hammer and the end of a socket wrench (Figure 14, 915).  Figure 15 (915) and Figure 16 (901) shows the flywheel seal installed.

     Now, it's time to install the pilot bearing, shown in Figure 17 (915).  This small bearing should also be replaced every time you perform a clutch job.  On the 915 transmissions, the installation is easy.  Simply attach the pilot bearing using the three bolts that were used to attach the old one.  It is not necessary to replace these bolts.  Figure 18 (915) shows the flywheel pilot bearing being attached.  Figure 19 (915) shows the flywheel pilot bearing installed.

     Installing the pilot bearing for the 901 transmission is a bit more tricky.  You need to take the pilot bearing and press it into your newly resurfaced flywheel, as shown in Figure 20 (901).  Lightly tap it with a hammer and be careful not to bang it in cocked, as this can damage the bearing.  Figure 21 shows the pilot bearing installed.

     You are now ready to install your flywheel on to the transmission.  You should always use a new or resurfaced flywheel in your clutch job.  Your clutch performance can be severely affected if you do not.  Figure 22 (901) and Figure 23 (915) show resurfaced flywheels.  On the 915 transmission, the starter ring is separate from the flywheel.  When you remove your old pressure plate, you should remove this starter ring from the plate.  Place the starter ring on the top of the engine in clear sight.  Almost every mechanic at one time has completely installed the 911 motor and forgotten to install the starter ring.  

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