Often difficult to engage 1st gear
Adjust the shift coupler as on manual car. Replace worn bushings if necessary.
‘Grabbing’ shifting from neutral/rough shifting
This is often the result of a poorly adjusted vacuum switch, which is attached to the intake manifold. An adjustment screw hardens and softens the clutch take-up.
The car becomes stuck in gear after being engaged for a few minutes
This is likely caused by a vacuum leak. Use the diagrams in the manual to identify vacuum lines and check for leakage/loss. A brake bleeding kit/vacuum tester is a useful tool for this job.
Car grinds when shifting into gears
If some gears will select and others won’t, this may be a problem with the micro switch on the shifter. Remove the boot from the base of the shifter and use a multimeter to check for current changes when the gear shift is moved. The microswitch needs precise adjustment and bending it should be avoided. Try cleaning the contacts first. Prise open the top plate of the micro switch with a small flat screwdriver. Clean the contacts with switch cleaning solvent and a fine brush.
Another possible cause of such problems is the degradation of the diaphragm in the vacuum servo. Over time, the seal may fail so it does not hold sufficient vacuum to operate the clutch. The bad news is that this part is not available from Porsche and basically non-rebuildable. All used ones are also nearly 40 years old. Some have reported successfully replacing this part with truck air brake components.
The sportomatic system is protected by a (5A?) fuse in the rear fuse box adjacent to the ignition system. Checking this should be your first step when diagnosing a complete shift failure.
Vacuum Servo
While previously NLA, it appears Porsche offers a rebuilding service for the vacuum servo. The part number of the original vacuum servo is 905 116 721 01. Entering this in the Pelican Parts search suggests an alternative, rebuilt servo. If anyone can confirm this service exists and rebuilt servos are available, please let us know.
Replacement Vacuum Hose
Vacuum hoses perish and can start to leak with age. Even a very small leak will cause your Sporto to give trouble. I recently replaced the hose to the vacuum tank on my car with silicone hose with 12mm inside diameter from ebay which appears to perform fine. However, the hose 905 108 703 00 that runs from the solenoid to the vacuum servo is specially shaped. This may be available from Porsche, but an alternative is also available, RAM hose RH7465 is reported to fit with no adjustment.
I agree with your thinking.
I agree with your thinking. Where I live in Antigua, I wished that many teachers testking would get caught up in using "funky technology". They seem that they are so terrified of it. When the Head of Department told us that we had to stop writing out the reports, and we had to input the grades on pmp certification the computer he got major objections. When I began at the College for vmware certification I would get movies to compliment the books, and I was asked by other students Are you guys watching watching Tv again? If time is changing I believe we as teacher should change with the times. If technology can help facilitate learning why not dive into it?
How to replace oil seals where drive shafts exit gearbox?
Hi everyone i am very new to the scene having become the proud owner of a 74 911S last week. The sporto is running fine (at present!) and i am used to driving it already.
There is however a small gearbox oil leak out of the exit point to one of the drive shafts.
Questions:
1:are replacement seals readily available from Porsche dealers worldwide or is it an item that could be simply purchased from a bearing/seals supplier?
2:are drive shafts relatively simple to remove?
3:are the seals removable without having to take the gearbox out of the car or the gearbox apart?
4: what engine oil do you recommend to help run these torque converters?
thanks for your help!
its good to be a new member
SC
Melbourne, Australia
DIY diaphragms?
"Some have reported successfully replacing this part with truck air brake components."
Can you find any more detail on this? I can see in my mind's eye groups of Sporto owners hanging around truck stops, and I think they should be going there with a clear purpose in mind. ;-)
It was fishcop on Pelican. He
It was fishcop on Pelican. He does mention the name of the part, its from an Australian supplier of air brake components to their trucking industry, so probably no hope of getting one outside of Oz. I found some of their brochures with similar parts in but couldn't find the one he mentioned.
Fishcop's response
Here's what Fishcop passed along to me: the part is "PBR VH 2502." A Google search on those terms turned nothing up for me. Am I missing something? It may be worthwhile to source it from Australia if no others can be found.
Update
Phil and all,
If you follow this thread on Pelican http://forums.pelicanparts.com/showthread.php?t=470611 you'll see that I've offered to work with John (Fishcop) to provide more info on this. Really John will do the heavy lifting of showing us how he did it; I'm simply going to try to find a similar part from North American truck suppliers. (Edit 24 May 2009: I've added pics of the diaphragm to that thread.)
Oh, and I guess you can figure that I'm teenchy here and at Early S but crater64 at Pelican. ;-)
Ed