Loose Pressure Plate Bolts - Closeout

[Bill Sargent]

I have been having a problem with the clutch in my 64 C cab for some time now. Symptom was like the clutch cable was stretching, but inspection of the cable showed no problems. Clutch would engage right off the floor. Adjustment of the clutch helped for a while but the problem returned. Sometimes the clutch would bind and the pedal could not be fully depressed, Removed the motor today and found the problem. The bolts holding the pressure plate to the flywheel had started to come loose, more so on one side. Bolts were torqued to spec with lock washers when installed (19 years and 8K miles ago), but no Loctite was used. Will use blue Loctite when I reinstall unless someone has other suggestions.

The throw out bearing had also worn a groove into the pressure plate fingers, mostly on the side that was looser. While I could probably reuse the pressure plate I am concerned about chatter, so will install a new balanced pressure plate I have.

Also found the fuel line under the car wet and leaking slightly from ethanol degradation - it took 19 years. So will also be replacing all the soft fuel lines, including (argh) the one in the tunnel. Another good reason to turn the pet cock off when not driving the car.

[C J Murray]

I strongly suspect that engine vibration caused the bolts to loosen. Most likely the clutch or flywheel is out of balance. I would replace the pressure plate bolts for fear of future failure. I never use Loctite on those bolts and have never had a problem even up to 9000 rpm. Check your crankshaft/flywheel endplay. Considering your situation I would have the machinist resurface and balance your flywheel. Install all new clutch parts.

[Vic Skirmants]

Bill; the fuel line in the tunnel is steel.

[C J Murray]

Bill; the fuel line in the tunnel is steel.

He means that short piece up front under the toe board. PITA to replace.

[David Jones]

Bill, when you say you used lock washers, are you talking split spring washers or wavy washers. I have always used wavy washers and have never had a bolt come loose in 55 years of very careful never exceeding red line driving in various VW's and Porsches.

[Doug McDonnell]

Sounds like you may have done it recently CJ ? https://porsche356registry.org/classifieds/28833

[Thomas Sottile]

ThAt is a sign from the Porsche Gods that are telling you to drive your car more

[C J Murray]

Sounds like you may have done it recently CJ ? https://porsche356registry.org/classifieds/28833

Yes!!!! When they sit is storage for 46 years they dry out and leak. Always great to open the garage door and be knocked over by the smell of gasoline. Somebody is going to get a really great car when they buy it from me. I had to do ALL of the little chicken sh*t repairs to the car but I can't think of anything left to do. 46 years in dry storage did keep it from rusting though. C coupes are really nice to drive.

[Thomas Sottile]

And SC are even better

[Jay Wiener]

HI Bill, my carrera ate a pressure plate as well

[Bill Sargent]

Hi Jay - was not the carrera. My pushrod 64 C cab has the problem. The carrera has a 904 flywheel so it has two of the 5mm spacers between the engine and trans. Seems quite happy.

[Al Zim]

The first thing i would do is to check if the bolt holes in the flywheel are countersunk 3MM or so below the level of the flywheel. The second thing I would do is to use an Allen bolt to hold the pressure plate down. These bolts are usually a 12KG. For lock washers I use a thicker serrated washer with a cut in it like a normal lock washer. Mind your torque so you do not stretch the bolts. al zim

[Dick Weiss]

Bill,

The pressure plate bolts should use the spring-ring lock (split) washers; NOT the spring (wavy) washers,
and alternately torque them to 18-22 ft. lbs.

Sounds like your clutch release fork is worn out--especially on the pull-arm side including the cross shaft
bushings in the bell housing; You may get by just replacing the left side as the right side will be
difficult w/the starter in the way.
As far as the diaphram spring finger tips are 1/2 +worn, it's time for a P/plate & release bearing.

Dick

[Dick Weiss]

I'll stand slightly corrected that my recent message mentioned that the spring-ring (split)
lock washers used on the P/plate would do the job; However, those are listed in the 'B' supplement
parts book including a change to the so-called "cheese-head " (allen) screws for the BT6 and 'C' series
vs. the wave washers used w/the hex head bolts on the earlier series clutch assembly.

[Dick Weiss]

Another follow-up on clutch assembly bolt lock washers:

There are @ least 2-versions of wave (spring) washer thickness, The thin (0,5mm) are for the late
aluminum rocker stand assembly retaining the rocker shafts along w/the thinner hex nuts--
check the parts book. The 0,75mm thick wave washers are used else-where.

Also, there are different sizes of washer diameters--the large version wouldn't be correct under 12mm
nuts vs. the 14mm hex nuts. (even the 13mm nuts)