The rear brakes and axles
Updated; August 29, 2008
To start off;
Some of the information given here may not apply to your car's configuration. So be careful.
What I want to do is convert to 944 CV joints and "M" brake calipers with vented rotors. (the 944 CV stuff will be added latter)
Stolen photos and information from the web;
I'm going to post up a bunch of photos from the web (914world) and will reference the page that they came from. I'm also going to let the individuals that originally took the photos know that I've posted them. So, it really isn't stealing. It's just passing on information that is already out there.
The other thing is that I don't want people to think that I thought up this stuff. I really don't know that much about what Porsche stuff interchanges.
Using "M" calipers and vented rotors;
It seems that Eric Shea was one of the first persons to do this conversion. You can go to a real good string written by Eric (on the 914 world site) by clicking here. In the string, he covers how to mount the parking brake assembly. What isn't covered is the hook-up of the cable.
Different methods of hooking up a parking brake cable can be found in the sting linked to by clicking here.
The following photo was shot by Eric Shea (link to string here) and I added the arrows.
The green arrows point to where the housing has to be ground down to clear the parking brake backing plate. The blue arrow points to the bracket that originally was for the dust cover, which also has to be ground off.
The next photo is also an Eric Shea photo with added arrows. (link here)
This shows the parking brake assembly bolted to the housing. The reason for the colored arrows is to show how the original 911 cable would attach.
In the stock configuration, the end of the parking brake cable would attach to the "spreader" pointed to by the green arrow. The sheathing (or housing) of the parking brake cable would rest against the "spreader" pointed to by the blue arrow. The spring between the two spreaders is commonly called a "helper" spring.
How this all works is that in the stock 911 configuration, the housing of the parking brake is free to move. When you pull on the parking brake lever, both spreaders are pulled toward one another. This forces out the brake shoes.
This is a great photo, but doesn't address something that will be talked about next.
The following photo was shot by 914Timo (link to string) and he added all the text shown.
What he is showing is that rectangular (40mm) plate that he welded to the brake backing plate. In a stock 911, this is a piece that's cast into the housing. The purpose is have something that indexes the shoes when adjusting them and also prevents them from working around the housing.
You can also see in this photo that the housing of the parking brake housing is free to move inward as the spreaders (called "expanding bow" in the photo) compress.
The next photo is one posted up by Larry Hubby (link to string here). I added the arrows. Larry also did an addendum post.
I like the solution that Larry came up with to connect the parking brake cable and I think this is what I'm going to do.
First off, he changed the angle that the bracket for the stock 914 cable points. It now points directly rear-ward. He shortened a 911 cable and welded a bracket on the arm for it. Then he interconnected the two cables by modifying the 911 cable.
The green arrow points to the new bracket for the end of the shortened 911 cable. The blue arrow points to the spreader bar.
This next photo is just an enlargement of the prior one.
It looks like Larry took a 40mm long section of angle iron and welded it to the housing after cutting out an opening for the end of the 911 cable housing.
The red arrows point to the welds. The blue arrows point to the two surfaces of the angle. The green arrow shows how the 911 housing clears the opening within the angle iron.
Axles, CV's, & hubs
I'm changing from the original 4 lug wheels to 5 lug and also have to mate to the Audi / VW transaxle stubs. If you are not doing the same exact thing, don't count on information here applying to your car!
This information comes from a 914world web page written by SirAndy. Click here for the page.
1. I need early (69-73) 911 hubs. This gets me the 5 lug hub and presses into the 914 wheel bearings. (901.331.065.09)
2. I need 75-84 911 (6 bolt, 100mm) stub axles. (Sir Andy lists the years applicable as 75-79)
3. I need 944 (100mm) CV joints, both inner and outer. This CV is used on a whole bunch of other cars and is available for a reasonable price.
4. I need to figure out what axles are the correct length. Keep in mind that the axle length is different from side to side. Sway-away has a whole bunch of them. (link to Sway-away).
The 944 CV will not bolt directly to the Boxster transaxle stubs, but an adapter shouldn't be hard to make.
The Audi stubs are for a tripoid type joint. I don't know how hard an adapter would be to make.
It seems that it would be possible to swap the Boxster (early 5 speed) stubs onto an Audi / VW 012 transaxle. The reason I say this is that they both use the same Quaife differential (same splines) and also have the same support bearings (part number 002 517 185, 46mm by 75mm by 18mm).
So there you go.
return to my site's entry page
Wes Vann