



Let’s see, what goes here. Whatever spills out, whatever I find important. Cars,of course! All kinds of fabrication, metal work, wood work, technology, whatever I manage to turn into a project. Politics, yep, some of that will spill out, hey, it’s my garage. Grab a beer and hang out a while...


I ran across this instructional video trying to find info about cylinder head milling fixtures online, and ended up renting it from Smartflix for $26… advertized as:
"This Three Volume Video Series Is Loaded With Tips On How To Get
The Most From Your Bridgeport Type Vertical Mill"
With a retail price of $80… you kind of expect something at least semi professional, ESPECIALLY since these guys have a whole series of instructional videos. WELL, that's not what you get. The rest of this post is a slightly edited version (mainly to remove/fix context specific stuff to make it make sense on it's own) of what I posted as a review on the smartflix site, which I somewhat suspect won't get posted because of being long and critical, we'll see:
On Smartflix site you can give a video 0-5 lightbulb, I gave it 3. I have to emphasize, for the most part this DVD set is such a hideous turd that there had to be something good here to get me to rate it anything above a 0, so I'll start there.
The good:
The bad:
So, did I learn something? Well, yea, I think I did, but most of what you see on YouTube or similar sites is better quality. It's really a shame, since it's obvious from watching the host of the video (I believe his name was Adrian Pendergrass or something similar from listening to the introduction) go through the his motions that he's quite familiar and comfortable with what he's doing and has some good information to share.




























Rebuilding the posi: There are pretty good, detailed instructions in the FSM and in the tech section on this site ( thirdgen.org ). Look them up, they’re a good start.
I’ll add a quick nutshell description and note where I did things differently/suggestions:
Disassemble: unbolt the axle retainers, pull the axles, pull the center section cover, remove the bearing caps (make sure that you remember what side everything came from so you can put it back like it came out), pop the carrier/ring gear assembly out of the housing. Note, this will require some prying and turning and make sure you save the side preload washers/shims so you can reinstall them like they came out. Be careful with them, they are machined out of a cast piece and can be brittle.
To perform the rebuild you need some kind of fixture to hold an axle. I took a chunk of wood, cut 2 shoulders to sit on top of my vice jaws, drilled a hole through the middle and then sliced it in half on the table saw to make some clamp/vise pads for the job:
Before you disassemble it check this spot out:
With it sitting on the bottom axle, housing bolts up, unbolt the smaller, center bolts and pull the end of the housing/ring gear off.
When you do that you’ll see this (except you’ll have it in the case side, not the ring gear side like in this pic):
If you lift the spider/cross/preload spring assembly off you’ll get this:
If you lift that side gear out of the end of the case you’ll see the pocket in the side cone where you put the shims, there will be one on each side of the case between the side gear and the cone (unfortunately I don’t have a good picture). You can use any shims that are small enough to drop into the machined area between the 2 and still fit around the axle. I usually use 10bolt or ford 8.8” pinion shims. Actually, the last time I think I just stopped by the local machine shop and got a stack of whatever left over shims they had approximately the right diameter.
* This is where I differ from the instructions on the site or in the FSM, forget measuring clearances or anything else, just load both pockets with as much shim as you can get in there and still reassemble the case completely. I’ve never seen one of these get so tight it doesn’t work right (if anything you’ll want it tighter, no looser) and you’ll be kicking yourself if you do any less and start spinning one wheel again sooner then you had to. The shim packs will probably have to be the same thickness on both sides.
From there the reassembly is the opposite of the disassembly, just make sure that you have both axles installed and fully bottomed before torquing all the bolts, if you don’t line up the splines in the side gears and cones before then it’ll be next to impossible to do with it assembled.
Now if the case is worn out of spec, you can still usually get some life out it. What happens is that there are some rings machined into the end of the cones and the case to contact if the case is worn down too far, if you cut them down you can get some extra life out of it.
This is what it looks like if the cone and case ends are worn to the point where they’re grinding into each other, case side. The numbered parts were originally put in for something else, but they do point out the points that are contacting and wearing that aren't supposed to:

What I’ve done before is machine those down till they no longer contact (as a matter of fact, I think I machined them down till I had over .125” clearance). Again, case side:

Eventually, after a few more rebuilds the cones/case will wear enough that they get too thin, and I started getting cracking around the opening that I mentioned to check above to see if it’s worn past spec. When that happened I pulled it all apart, bevel ground the sides of the cones, centered them up in the housing using the axles and welded them in, like this:

