Manual for 914-6, want to change shifter bushings Options

[shepmon]

Hi all, Can someone suggest a manual for the mechanically challenged. I'm trying to improve my shifting on a factory 914-6. I got a set of bushings but don't know where they are on the car and how to change them. Also thinking about a RennShift but wanted to try the bushings first. Any thoughts would be appreciated. Thanks, shep

[Jeroen]

You could try the Haynes... not sure if the procedure is described in there though

[lapuwali]

If this is a real 914-6, then the only help you'll get is the exploded diagram in the Haynes manual for the tail-shift linkage on the /4, (aka the "early" linkage), which is the same as the 914-6 linkage.

[Porsche Rescue]

The linkage and bushings are different on 6 vs 4 tailshifter. And you're in luck, the 6 is simpler.
First bushing will be the cylindrical shaped cup at the bottom of the shift lever. Remove the 5 bolts and lift the lever up. The bushing will probably be in several pieces with some remaining in the cup of the shift rod. You will note that the two 10mm bolts hold a metal ring which should have a round plastic bushing inside. Likely it is in pieces on the floor of the tunnel. Once you remove the set screw and pull the cup off the shift rod you can slide the ring forward and off. Put in a new bushing and reinstall. Lube the cup bushing and use a soft hammer to pop it on the end of the shift rod.
If you are going to replace the firewall bushing you will need to separate the front and rear portions of the rod at the rear of the tunnel, under the center cushion. It is the hardest to replace. I find it helpful to boil it in water in the microwave and then push it into the firewall from the rear by prying (and swearing) with a screwdriver.
There is another round bushing in a bracket on the tranny (same bushing as used in the front guide ring). You must unbolt the bracket from the tranny and remove the rear shift rod with bracket to the bench. You then drive out a roll pin to remove the selector piece at the back end of the rod. Then you can slide the bracket off and install a new bushing. Note orientation before removing the pin because the selector must go back in the same position. If it is 180 degrees off it won't line up.
There is also a plastic piece in the joint at the front of the rear rod which can wear. I have never replaced one so can't offer any help there.
Then you need to adjust the linkage after reassembly. Post again when you get there, or sooner if more help is needed.

[Red-Beard]

a couple of additional things.

Test fit the bushings over the shift rods while they are out of the car. Before removing the rods, mark with a permanent marker the fore and aft points of contact of the bushing and the rod.

Now, if the new bushings seem loose on the test fit, build up some material on the shafts at these points. I have used brazing rod and lead plumbing solder. I now think that JB weld would be the easiest thing to use. You want to build up the rod, then sand it down to give you the best fit in the bushings.

Rebuilding the bushings in the linkage is only 1/2 of the job. The other half is changing the bushings and the centering spring in the shifter itself. Cost of the parts was $45 from a Porsche dealer. Parts are listed on the last page of my tranny rebuild article.

http://home.san.rr.com/pb914/rebuild/

Lastly, the best thing you can do for shifting is to convert the Factory 6 tranny to sideshift the next time you have the tranny rebuilt. This did more to fix my shifting issues than anything else!

[lapuwali]

The linkage and bushings are different on 6 vs 4 tailshifter. And you're in luck, the 6 is simpler.

How so? The only 6 I've taken a good look at had a linkage that looks identical to the linkage on my '71 /4.

[Red-Beard]

The 4 makes a jog to the left at the firewall and the tail cover rod stick out to the side. I think this was to get around the heat exchangers. Not entirely sure as I've never owned a tailshift 4. The connection between the shift linkage and the tail cover rod are different as well.

So, the 4 has 1 more peice of shift linkage and 2 more bushings (The round plastic balls on the firewall) for slop than a tail 6.

Internally, the tail 6, tail 4 and the 911 tranny shift the same way. And that linkage has slop too!

[Porsche Rescue]

Red Beard can answer better than I, but the biggest difference is that the six linkage is relatively straight from the firewall to the tranny tail.
The four has a "dog leg" just after the firewall which takes two ball shaped bushings. The six has a sort of "u joint" after the firewall which does not exist on the four. Very different.

[Porsche Rescue]

He types faster than me too.

[lapuwali]

Interesting. I guess that "original 6" I was looking at wasn't so original. Hardly the first time that happened.