Repairing 928 gear shift (socket ball out)
12-17-2010, 05:12 PM
#1
Instructor
Thread Starter
Repairing 928 gear shift (socket ball out)
Hi. First of all, as I promised on a previous thread I will publish here some thoughts and pictures of a repair I'm working on on my 928 to see if somebody can tell me if I'm doing something wrong (or even good). Any comment will be extremely useful for me (and for sure for future readers with the same problem).
I'll try to include some photos and schemas for making it a bit more interesting... also for people that read this post in the future and like to know whats under their cars before getting there.
Facts you should know:
-I don't have a deep mechanic knowledge (only bravery
), but I bought this car to learn and try to avoid going with it to the workshop. In any case I'm doing things with time and extreme care, and following its great workshop manual).
-I'm from Spain, so sorry about my language mistakes.
-The car is a 1980 4474cc 928 (not 'S') with a 10 digit vin starting with 92A080xxxx, five speed gear shift. I bought it with a known gear shift failure. I know it hasn't run in two years since this failure happens but I know that before that it runs good (passed all tests old cars has to pass each year for safety reasons in my country, and they are severe with brakes, engine, exhaust testings, etc).
-Looks good inside, outside and looking at the engine too. I take this opportunity to show it to you with some pictures:
The problem: The 'socket ball' (PICTURE1) at the end of the front 'guide tube' of the gear shift is out of place, it should be inside the welded ball (PICTURE2) at the end of the central tube and is NOT.
The reason of this post is mainly to ask the experts how many things I should and should not need to remove or disassemble in order to have the gear shift back to work.
I have been reading the workshop manual and unmount the shift lever from inside. PICTURE3 is a view of the unmounted gearbox sitting on the drivers seat. I would have liked to extract the 'guide rod' (the left rod in picture3 and the part number 3 in the schema below) to see if it is straight, but I havent been able to do it, and don't know if it is possible. The rod is loose, but not easy angle nor from inside the car neither from the bottom.
Also unmount the exahust to watch the socket ball from the bottom of the car and have limited access to it but at least I can see things. Also dont know the force needed to insert the socket ball inside the welded ball (seems hard)...
Reading the manual it explains the instructions for mounting correctly the ball socket and guide rods and shows very precise schemas with correct angles (PICTURES 4, 5 and 6) between rods and lever when mounting and they do it all out of the car, so I suppose that I will need to extract the whole central tube and guide rods and shiftlever like in the schemas of the manual to adjust it well, away from the car.
The thing is that I'm not sure if I will have to take out of the car the complete shift system (like in PICTURE5) and if the answer is yes, then, what parts of the car I will need to take apart before to be able to take the shift system out.
Underneath the guide rods of the gear system is the 'central tube', to the front of the car to the clutch (PICTURE7) and to the rear to the transmission case (PICTURE8). In picture7 and hidden by the tube is the famous 'socket ball'.
The 'central tube' is linked to the transmission case, the transmission case is over the 'rear axle cross member' (PICTURE8)... so the questions that comes to my mind right now are:
To take down the 'central tube' and the gear system outside of the car... what do I also need to remove?:
- Is it necessary to extract the transmission case or is it possible to unscrew the central tube from it and then be able to take down the 'central tube' and gear shift?.
- If the answer is that I need to take out the trans case, then will I need to take down the whole rear axle cross member for doing it?. Seems a bit crazy that for setting up the socket ball and the gear shift rods aligned I will need to take apart the whole rear axle...
I would really appreciate any comment about my thoughts, everything will be useful. Thanks a lot!.
ps.- sorry for the long post... too many pics
I'll try to include some photos and schemas for making it a bit more interesting... also for people that read this post in the future and like to know whats under their cars before getting there.
Facts you should know:
-I don't have a deep mechanic knowledge (only bravery
), but I bought this car to learn and try to avoid going with it to the workshop. In any case I'm doing things with time and extreme care, and following its great workshop manual).-I'm from Spain, so sorry about my language mistakes.
-The car is a 1980 4474cc 928 (not 'S') with a 10 digit vin starting with 92A080xxxx, five speed gear shift. I bought it with a known gear shift failure. I know it hasn't run in two years since this failure happens but I know that before that it runs good (passed all tests old cars has to pass each year for safety reasons in my country, and they are severe with brakes, engine, exhaust testings, etc).
-Looks good inside, outside and looking at the engine too. I take this opportunity to show it to you with some pictures:
The problem: The 'socket ball' (PICTURE1) at the end of the front 'guide tube' of the gear shift is out of place, it should be inside the welded ball (PICTURE2) at the end of the central tube and is NOT.
The reason of this post is mainly to ask the experts how many things I should and should not need to remove or disassemble in order to have the gear shift back to work.
I have been reading the workshop manual and unmount the shift lever from inside. PICTURE3 is a view of the unmounted gearbox sitting on the drivers seat. I would have liked to extract the 'guide rod' (the left rod in picture3 and the part number 3 in the schema below) to see if it is straight, but I havent been able to do it, and don't know if it is possible. The rod is loose, but not easy angle nor from inside the car neither from the bottom.
Also unmount the exahust to watch the socket ball from the bottom of the car and have limited access to it but at least I can see things. Also dont know the force needed to insert the socket ball inside the welded ball (seems hard)...
Reading the manual it explains the instructions for mounting correctly the ball socket and guide rods and shows very precise schemas with correct angles (PICTURES 4, 5 and 6) between rods and lever when mounting and they do it all out of the car, so I suppose that I will need to extract the whole central tube and guide rods and shiftlever like in the schemas of the manual to adjust it well, away from the car.
The thing is that I'm not sure if I will have to take out of the car the complete shift system (like in PICTURE5) and if the answer is yes, then, what parts of the car I will need to take apart before to be able to take the shift system out.
Underneath the guide rods of the gear system is the 'central tube', to the front of the car to the clutch (PICTURE7) and to the rear to the transmission case (PICTURE8). In picture7 and hidden by the tube is the famous 'socket ball'.
The 'central tube' is linked to the transmission case, the transmission case is over the 'rear axle cross member' (PICTURE8)... so the questions that comes to my mind right now are:
To take down the 'central tube' and the gear system outside of the car... what do I also need to remove?:
- Is it necessary to extract the transmission case or is it possible to unscrew the central tube from it and then be able to take down the 'central tube' and gear shift?.
- If the answer is that I need to take out the trans case, then will I need to take down the whole rear axle cross member for doing it?. Seems a bit crazy that for setting up the socket ball and the gear shift rods aligned I will need to take apart the whole rear axle...
I would really appreciate any comment about my thoughts, everything will be useful. Thanks a lot!.
ps.- sorry for the long post... too many pics
12-17-2010, 05:30 PM
#2
Rennlist Member
A much simpler fix would be to place the socket on top of the ball then pull it down onto the ball using a rope or strap. You could tighten the rope by twisting it (like a tourniquet) until the socket snaps back on to the ball. Then when your done place a large plastic tie-wrap over the shifter tube, holding it to the central tube. The tie-wrap will prevent the socket from coming up and off the ball in the future. With this procedure no disassembly is required.
12-17-2010, 10:59 PM
#4
Rennlist Member
As I mentioned before, you should get Roger's (928srus) short shift kit. It elimnates the whole front ball assembly. If you do it this way it will 1) be a big pain to do the job, 2) break again in a few years, 3) still not shift as well as it might. Roger's solution is a permanent fix, easy, and will shift better.
12-18-2010, 11:30 AM
#5
Rennlist Member
Rennlist Site Sponsor
Replacing the front shift cup onto the ball should be quick and easy. Put some grease inside the cup, set it over the ball, and force it on. You can use a twisted rope or strap as already suggested, or what we call a "ratcheting tie-down strap", or a large screw-type hose clamp, or pry bars, or anything else that will force the cup onto the ball. Don't worry about the adjustments - if it worked before it popped off, it will work when you put it back.
The main problem with that is that the cup probably popped off because the plastic liner inside the metal cup has worn or broken, and it will eventually pop off again.
The temporary fix is to put a large hose clamp or some sort of strap around the shift rod and torque tube to keep the cup from popping off. It should be just tight enough to hold the cup on, but not tight enough to keep the shift rod from moving slightly. This "temporary" fix will work for a long time.
You can replace the plastic lining in the cup. While that was never a Porsche-approved fix, you can get a cup from us or the other vendors that will work. The Porsche-approved fix is to replace the entire metal cup and liner. This is more expensive, and quite a bit more difficult to do with the torque tube in place, but you can do it. If you replace the cup assembly, you do need to worry about the adjustments.
There is a support bearing just forward of the shift lever housing. If you pull the rubber seal aside (from inside the car) you can see the support. There should be a plastic ring around the front shift rod inside the rubber support. If this ring breaks up, the shift rod will be looser, making shifting less precise. You can try splitting a plastic ring to go around the shaft inside the rubber support. Replacing this support assembly would be really difficult.
The main problem with that is that the cup probably popped off because the plastic liner inside the metal cup has worn or broken, and it will eventually pop off again.
The temporary fix is to put a large hose clamp or some sort of strap around the shift rod and torque tube to keep the cup from popping off. It should be just tight enough to hold the cup on, but not tight enough to keep the shift rod from moving slightly. This "temporary" fix will work for a long time.
You can replace the plastic lining in the cup. While that was never a Porsche-approved fix, you can get a cup from us or the other vendors that will work. The Porsche-approved fix is to replace the entire metal cup and liner. This is more expensive, and quite a bit more difficult to do with the torque tube in place, but you can do it. If you replace the cup assembly, you do need to worry about the adjustments.
There is a support bearing just forward of the shift lever housing. If you pull the rubber seal aside (from inside the car) you can see the support. There should be a plastic ring around the front shift rod inside the rubber support. If this ring breaks up, the shift rod will be looser, making shifting less precise. You can try splitting a plastic ring to go around the shaft inside the rubber support. Replacing this support assembly would be really difficult.
12-18-2010, 01:06 PM
#6
Instructor
Thread Starter
And the hint of setting a large plastic tie-wrap is also one of this hints I was looking when start the post. This probably will solve the problem for longer time.
Originally Posted by fraggle
Great shots and common problem. Jim M is right on here!! Great looking car!
Originally Posted by karl ruiter
As I mentioned before, you should get Roger's (928srus) short shift kit. It elimnates the whole front ball assembly. If you do it this way it will 1) be a big pain to do the job, 2) break again in a few years, 3) still not shift as well as it might. Roger's solution is a permanent fix, easy, and will shift better.
Could be a similar to this one the one you are talking about?...
http://www.youtube.com/watch?v=VWa5Q0rQRZM
Originally Posted by WallyP
or what we call a "ratcheting tie-down strap", or a large
It is possible that the metal cup you see in PICTURE1 is new. I'm not sure but it is brighter than other parts around and I think that the previuos owner maybe bought it but didnt finish the repairing before selling the car, so probably the plastic liner is ok. I'm not sure. What I could say is that the cup right now do not enter easily in the ball. I still havent tried with the ratcheting or grease. But knowing this is the way to do it, I'm sure I will make it enter in its place. In any case when I snap it in back again I will do the plastic tie wrap trick.
I have been watching the front 'guide rod' with care or at least the part that I can see without removing the torque tube, and I'm not sure, but it could be a bit bended. And I'm wondering if there will be a way of taking out this rod for changing it for a new one.
If insert my finger through the rubber seal along the front guide rod I touch what I think is the plastic ring. I suppose this is what in the PET catalog is called 'bearing bracket' and in the workshop manual they call 'guide rod bracket', and dont know if this could be take apart easily, from inside or from the bottom of the car. I suppose that if I can unmount this part, then I will be able to extract the guide rod and change it by a new straight one without problem.
I think WallyP is talking me about this exact part, but dont understand very well your two last phrases. Also dont know if this particular ring is broken or not, because of the rubber I can not see very well there, neither from the bottom.
Thanks a lot for your help!.
