Title says it all. I have access to a mill and a lathe, I just need to know how much to mill and if I do both sides evenly. Also, how do I know if it isn't fixable? I am shimming my rear end and I need to mill them.

 

Bump, I am trying to get this done tomorrow at school, and fix it after school because I work the rest of the week.

 

Also, how do I measure to see what size shim I need?

 

Nobody knows how to mill a posi cone??? Wow, I guess I might be on my own

 

I wish I had an answer for you. I know nothing about 9 bolts, but I know some about milling. In my 10 bolt (and any other rear end I've ever seen) each and every moving part that makes contact with any other moving part is EXTREMELY hard. Like if you were to try cutting one with a HSS cutter, the cutter would probably melt down. An indexable carbide cutter could maybe work. Can you surface grind it instead?

 

Well, I have everything, Mills, laths, All with Carbide tips, I have grinders... the whole shebang. I Know it needs to be perfect though. I guess I Will mill them and get rid of the lip on the one, then mill the other one to the same size.

 

Ok I've done this recently. If you search for "posi cone repair" and simular searches you'll find a post where I replied to the same question just a month or so ago. In the post there's a link to an article that has pictures. It's a really good article and worth finding.

Basically I took 0.100' off the outer ring and inner hub of the small end of the cone. This allows the cone to move farther into the housing. I used a mill but a laythe would be fine.

As far as shimming you put the cone in the housing and place the spider with gears on top. If you hold the spider in place you can move the cone up and down to get a feel for how much shim to use. You just want to remove all the play without binding it. I went to the Ford dealer and a mechanic there gave me a handful of pinion shims and they worked great. I used a syntheric gear oil with no posi additive.

And if it goes well for you you'll be very pleased. My car hooks up great. no more breaking the inside tire loose in turns and I can do very controlled donuts and drifts like never before!

Ok I found this article. Here's a couple of ways to get it.

do a web search for;

BW 9-bolt positraction cone repair

or this link may work

http://www.geocities.com/luckyducky_...air30Nov04.pdf

Good luck.

 

Did you take that much out of both sides equally?

 

Yes, I started at 0.050" per side and kept milling more until I got what I thought was enough clearance from bottoming out. When you put the cones in the housing, you can see the cone to housing clearance through a couple of holes in the diff housing. If you check it out you'll see what I mean.

 

I finished mine a few hours ago. I used a lathe, But they aren't exactly even. They are flat though. I tried to get them perfectly even, but there wasn't anyway to measure. I only took off like .025 or so. The shims will fix the difference though I guess.

 

They don't have to be perfectly even IMO. Just provide clearance so they don't bottom out in the housing. Mine were worn pretty bad so I had to take the max off. And 0.100" is about the max! Anyway, put them in the housing and you can check to see if they bottom out. What I mean by bottoming out is the face of the small end should NOT contact the housing. If they do or are real close to, I recommend taking more off. I left about 0.050" between the small end of the cone and the housing. They will wear further into the housing with use. If they do end up bottoming out the posi will be ineffective. The friction points is the tapered surface of the cone and it must be tight against the housing. One more thing, the shims take clearance out from BEHIND the cones (big end). The bottoming out is in FRONT of the cones (small end). The shims have nothing to do with how much is removed from the cone small end.

 

It is all back together. Now, I can't figure out how to get the carrier in with those spacers on each side. I can take them out, put the carrier in, but then the spacers wont go back in no matter what I do. Can anyone help me get them both in?

 

It'a a little tricky. What I do is hold the diff with the bearing reces and shims on each side and start the assembly in the housing. It has to be straight and lined up. When I get the assmy about half way in I slide the shims on the passengers side in, then wiggle it a bit and let the diff slide into place with the drivers side shims about half in and half out. When I get the diff into place then I slide the shims on the drivers side the rest of the way in. Sometimes I have to tap the shims into place. Be careful and dont force it more than you have to. If (when) the bearing races get cocked a bit the whole thing won't go. Be patient and try it a few times. You may need an assistant to help you hold it cause, as you know, it gets heavy after a while (I'm usually by myself lying on my back) and hard to keep it just right and support the weight.

 

Well, I can get one side in then put the carrier in, but then there seems like there is absolutely no more room for another one.