901 ZF LSD rebuild, 30 years of parts collecting pays off Options

[mgphoto]

Hello,
I started collecting parts of this project 30 years ago and the last parts have fallen into place.

In this post I hope to clear up some confusion and convey some of what I found trying to complete this project.

First piece


purchased form PAR in Yonkers NY 1986 914.332.209.00 casting number 51D

The LSD found its way to me in 2013 from the venerable Cap'n Krusty



The diff needed some work as it was missing internal spring plates which are NLA.

Item number 4 in this factory illustration.
This part places tension on the clutch pack which is measured as drag.
The factory spec on this is 29 - 58 ft. lbs

This item can be replaced by what is now called a "cup" spring from and early 928
part no. 928.332.555.00

seen here as item number 10

As for the internal wear parts, the 914 parts are NLA but, get this they are replaced by mostly 917 parts! WAY COOL.

Just the beginning, stay tuned!
Mike

[mgphoto]

OK here are a few tidbits about the ZF LSD.

Below is a link to thesamba.com website, lots of good info there too.
ZF LSD Diffs

This image shows all of the LSD diffs that are for 911's '64 - '88 this includes the 914, I thought someone would be interested in the variations.

We are interested in the late 901.
The image shows the external dimensions.

The late 901 ZF LSD which I will call the 914 from here on require a different transmission drive flange from stock. The 914.332.209.00 which has a longer output shaft than the standard flange 914.332.209.10, about 63 mm long, about 5 mm longer than the stock flange.


Here is a picture showing that dimension.

This image is the 901.332.209.21 it has the same shaft but the flange takes a larger cv joint about 110 mm, this is a good upgrade if power is on your mind.



At this point I have to mention that there are a number of output flanges out there but they don't fit.
There is one for sale on Ebay part number 914.332.209.00/10 it has the correct length shaft but it has 2 flaws.

Looks pretty good but looks can be deceiving. The land for the oil seal is 5 mm longer than necessary so this negates the longer shaft. Additionally the shaft itself is almost 2 mm thinner than the 914.332.209.00.

I bought one to see if it was possible to use. I took it to a machine shop to see if it could be modified. The answer is basically no. The flange is hardened steel, so all of the steel lathe tools would bounce off the piece not cutting it, I would have to try a machine shop that specialized in grinding as stones may be able to cut the material, but that still left the 2 mm difference in the shaft, which I am sure, after time would begin to vibrate and shake itself loose. Not a pleasant thought.

I've had one of the drive flanges on my shelf for years and I had to search for another, that was not easy. I searched the web and found a few sites with the part number but each time I ordered I received either a stock flange or some other incorrect number that looked good to someone else ie: 914.332.109.02 This is exactly the same dimensions as the stock unit but I can not find any parts catalog with this number.

So here is the biggest problem with using this LSD the drive flanges are rare as hens teeth. And the /6 guys think they have it tough finding parts.
OK more to come later.
Mike