1975 914 new shift coupling bushings very loose

[Buische]

I received the Pelican Parts white shift coupling bushings this week, and found that they fit very loosely in the hole, and the pin fits even more loosely in the bushing. Tech guy could not find any possible reason they were the wrong part (911-424-223-03). I tried to have customer service find out what the supplier said the OD and ID should be, but they only were told the parts came from Porsche. Probably means they are correct...but...

The tech guy suggested that my coupling was worn out, but I did not get that impression when pulling it apart. The bushings were crystalized and breaking up but not fitting sloppily, neither OD or ID.

I thought maybe the shaft assembly could be a remanufactured unit where over/undersided bushings/pin/coupling bores might be the repair, but I have not found over/undersized bushings in a web search.

I am hoping someone in the 914 or 911 community has known good parts or a factory service manual with dimensions and limits for rebuild, and can tell me what I should expect for my parts or for the new bushings, to know where the problem(s) lie.

With a micrometer, I measured the new bushings at 0.890" OD/0.510" ID (22.606 mm/12.954 mm), and measured my parts at 0.909" bore/0.475" pin (23.089 mm/12.040 mm). The bushing is loose by 0.019" and the pin is loose by 0.035".

I don't want to keep ordering and returning parts. I'm thinking I may use 0.010" feeler gauges for the bushing OD and figure out some kind of super thin tube for the pin, if I can't get parts that fit well some other way.

Any experience, helpful information, and maybe good used parts or knowledge of alternative coupling that is not expensive would be appreciated.

I bought the car 1.5 years ago, have put thousands into it, and have hardly driven it to know I love it and want to keep it. So many things not working right or just not safe. I am fascinated by the mid-engine layout with the American engine and cooling system in this particular car, and hear they handle so well. Plan is autocross, winding country roads (few in Central Illinois) and runs to Coffee and Cars on Saturdays. Don't want to sink more into it for "really nice" until I know I want to keep going.

Thanks,
Chuck

[roblav]

They suck. I made my own in a lathe.

[Buische]

Well, I learned that the width across the slot was the one to compare to the pin, so that cut down the inside clearance to maybe ok if bushings were squeezed. Then I remeasued the bushing and that closed things down on the OD a little. So I made a bush fix (sounds better than shade tree fix). I cut a 0.010” feeler gauge into 6 pieces and crammed them in on one side of the bushings, three per side, diagonal from each other to reduce slop a little more at the pin, with these shims next to the flat on the ID. Needed 0.030” per bushing to close down the 0.0025” pin clearance, even though the ID clearance was 0.020”. It worked well enough to ship it. Moving on. Should last a couple of years, after which I may want a fancy u- joint setup.

Folks in other message boards weren’t kidding about the firewall bushing. I ended up working an edge in, then using a short and wide screwdriver to push the lip in around the bushing. The last bit was pretty hard. My arms will hurt for days, but it’s done.

[Dave at Pelican Parts]

Note that the part number starts with 911. These superceded the 914 part number ones. Supposedly the older bushings fit better, and the 911 ones are designed with a little slop in at least one direction.

I cannot verify that, as I haven't seen the old ones to measure; by the time we started hearing lots of complaints, the 911 part was the standard one.

It's possible that 914rubber is making ones that fit better, but I'm very much not certain about that.

--DD

[roblav]

I bought mine from 914 rubber, and it still sits in my "unused new parts" bin.